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2012 Volume 40 Issue 11
2012, 40(11): 1635-1641
doi: 10.3724/SP.J.1096.2012.20151
Abstract:
To fabricate the aflatoxin B1 immunosensor, graphene oxide, 2,5-di-(2-thienyl)-1-pyrrole-1-(p-benzoic acid) and chloroauric acid were electrodeposited on the gold electrode surface in sequence. Then aflatoxin B1 (AFB1) antibody was covalently connected to the conducting polymer film with 1-ethyl-(3-dimethyl-aminopropyl)-carbodimide/N-hydroxysuccimimide (EHC/NHS) as activator and 1,3-dibutyliminazolium hexafluorophosphate ionic liquid was finally coated on the modified electrode. The Fe(CN)63-/4- phosphate buffer solution (pH 7.0) was employed as base solution for investigating electrochemical performances of the immunosensor by cyclic voltammetry and electrochemical impedance spectroscopy. Research revealed the introduction of graphene and gold nanocomposite obviously improved electron transfer rate of the modified layer, and the apparent electroactive surface areas of the electrode also increased up to 0.2188 cm2 and 0.2640 cm2 from 0.1772 cm2 of bare gold electrode, respectively. When aflatoxin B1 concentration is in the range of 3.2×10-15-3.2×10-13 mol/L, the electron transfer impedance responses of the sensor will linearly increase. The correlation coefficient (R2) and the detection limit were found to be 0.994 and 1.1×10-15 mol/L. The electrochemical response of the immunosenor can keep almost constant after stored at 4℃ for 20 weeks. Sensitivity and stability of the proposed method are better than those of other methods reported in literatures, it has been successfully applied to determination of trace AFB1 in peanut samples.
To fabricate the aflatoxin B1 immunosensor, graphene oxide, 2,5-di-(2-thienyl)-1-pyrrole-1-(p-benzoic acid) and chloroauric acid were electrodeposited on the gold electrode surface in sequence. Then aflatoxin B1 (AFB1) antibody was covalently connected to the conducting polymer film with 1-ethyl-(3-dimethyl-aminopropyl)-carbodimide/N-hydroxysuccimimide (EHC/NHS) as activator and 1,3-dibutyliminazolium hexafluorophosphate ionic liquid was finally coated on the modified electrode. The Fe(CN)63-/4- phosphate buffer solution (pH 7.0) was employed as base solution for investigating electrochemical performances of the immunosensor by cyclic voltammetry and electrochemical impedance spectroscopy. Research revealed the introduction of graphene and gold nanocomposite obviously improved electron transfer rate of the modified layer, and the apparent electroactive surface areas of the electrode also increased up to 0.2188 cm2 and 0.2640 cm2 from 0.1772 cm2 of bare gold electrode, respectively. When aflatoxin B1 concentration is in the range of 3.2×10-15-3.2×10-13 mol/L, the electron transfer impedance responses of the sensor will linearly increase. The correlation coefficient (R2) and the detection limit were found to be 0.994 and 1.1×10-15 mol/L. The electrochemical response of the immunosenor can keep almost constant after stored at 4℃ for 20 weeks. Sensitivity and stability of the proposed method are better than those of other methods reported in literatures, it has been successfully applied to determination of trace AFB1 in peanut samples.
2012, 40(11): 1642-1647
doi: 10.3724/SP.J.1096.2012.11370
Abstract:
A novel immobilized method, "click" reaction, was employed to capture glucose oxidase (GOD). First, azido-terminated carbon nanotubes (CNTs-N3) were obtained by bifunctional azide molecule (amine-PEG-azide) and alkynyl-modified GOD (alkynyl-GOD) was also synthesized. Subsequently, CNTs-N3 was reacted with alkynyl-GOD in a copper-catalyzed click reaction. Finally, the mixture was dipped onto the surface of glassy carbon electrode with the help of Nafion to construct a highly sensitive biosensor for the detection of glucose. The results of the both click reaction were monitored by IR spectroscopy, and the electrochemical performance of the modified electrode was studied by cyclic voltammetry and chronoamperometry. Under optimal conditions, the developed sensor exhibited fast response to glucose and the linear ranges were 6.0×10-7-1.4×10-3 mol/L with a detection limit of 2.0×10-7 mol/L (at 3σ). The proposed biosensor exhibited high sensitivity, long-term stability, excellent reproducibility. In addition, the serum samples were analyzed by this biosensor with satisfactory results.
A novel immobilized method, "click" reaction, was employed to capture glucose oxidase (GOD). First, azido-terminated carbon nanotubes (CNTs-N3) were obtained by bifunctional azide molecule (amine-PEG-azide) and alkynyl-modified GOD (alkynyl-GOD) was also synthesized. Subsequently, CNTs-N3 was reacted with alkynyl-GOD in a copper-catalyzed click reaction. Finally, the mixture was dipped onto the surface of glassy carbon electrode with the help of Nafion to construct a highly sensitive biosensor for the detection of glucose. The results of the both click reaction were monitored by IR spectroscopy, and the electrochemical performance of the modified electrode was studied by cyclic voltammetry and chronoamperometry. Under optimal conditions, the developed sensor exhibited fast response to glucose and the linear ranges were 6.0×10-7-1.4×10-3 mol/L with a detection limit of 2.0×10-7 mol/L (at 3σ). The proposed biosensor exhibited high sensitivity, long-term stability, excellent reproducibility. In addition, the serum samples were analyzed by this biosensor with satisfactory results.
2012, 40(11): 1648-1653
doi: 10.3724/SP.J.1096.2012.20196
Abstract:
The molecularly imprinted polymers (MIPs) capable of extracting triazines from food samples were prepared by suspension polymerization using butylmelamine (BME) as template, methacrylic acid (MAA) as monomer and ethylene glycol dimethacrylate (EDMA) as cross-linker, respectively. Molecular modeling approach was used to screen the most suitable dummy template. The selective adsorption of MIPs was evaluated by high performance liquid chromatography. The synthesized MIPs were used as the solid phase extraction (SPE) materials. The optimum loading, washing and eluting conditions for molecularly imprinted solid phase extraction (MISPE) were established to obtain high selectivity and sensitivity. Compared with commercial SPE columns, MISPE exhibited selective binding properties for triazines, and the matrix effect was significantly decreased. The recoveries of all 10 triazines in matrix spiked samples were ranged from 87.8% to 105.2%, with the relative standard deviations (RSD) below 13% (n=6).
The molecularly imprinted polymers (MIPs) capable of extracting triazines from food samples were prepared by suspension polymerization using butylmelamine (BME) as template, methacrylic acid (MAA) as monomer and ethylene glycol dimethacrylate (EDMA) as cross-linker, respectively. Molecular modeling approach was used to screen the most suitable dummy template. The selective adsorption of MIPs was evaluated by high performance liquid chromatography. The synthesized MIPs were used as the solid phase extraction (SPE) materials. The optimum loading, washing and eluting conditions for molecularly imprinted solid phase extraction (MISPE) were established to obtain high selectivity and sensitivity. Compared with commercial SPE columns, MISPE exhibited selective binding properties for triazines, and the matrix effect was significantly decreased. The recoveries of all 10 triazines in matrix spiked samples were ranged from 87.8% to 105.2%, with the relative standard deviations (RSD) below 13% (n=6).
2012, 40(11): 1654-1660
doi: 10.3724/SP.J.1096.2012.20492
Abstract:
Tourmaline was decomposed by using alkali fusion, and then separated and purified by three different procedures. It is found that both Fe3+ and Al3+ ions that are rich in tourmaline samples seriously affect the accurate determination of boron concentration by azomethine-H spectrophotometric method and also cause the loss of boron by specific adsorption when large amount of amorphous hydroxide precipitate formed in ion exchange columns. The addition of small amount of EDTA can eliminate the influence, but brings serious isobaric interference on boron isotopic analysis by TIMS. Finally, we establish a three-column ion-exchange procedure including the first mixed resin column, the peristaltic pump coupled boron specific resin column, and the second mixed resin column, which ensures the full recovery of boron (about 99%) from tourmaline samples with complex matrices. The positive thermal ionization mass spectrometry (PTIMS)-Cs2BO2+-static double-collection method was established by selecting H3-H4 Faraday cups and optimizing parameters in Zoom Optics (Focus Quad: 15; Dispersion Quad: -85) in a Triton TI mass spectrometer. The determined average 11B/10B value of NIST SRM 951 is 11B/10B=4.05044±0.00012 (2σ, n=8, 1 μg B), which is superior to the dynamic collection method in internal/external precision. A δ11B value of-0.3‰ for NIST SRM 951 through the same pretreatment procedure was obtained, indicating that there was no isotopic fractionation occurred during the extraction procedure. The comparison of boron isotopes in natural samples by TIMS and MC-ICP-MS after chemistry procedure turns out that δ11B values determined by the PTIMS-Cs2BO2+ method are in good agreement with that by MC-ICP-MS.
Tourmaline was decomposed by using alkali fusion, and then separated and purified by three different procedures. It is found that both Fe3+ and Al3+ ions that are rich in tourmaline samples seriously affect the accurate determination of boron concentration by azomethine-H spectrophotometric method and also cause the loss of boron by specific adsorption when large amount of amorphous hydroxide precipitate formed in ion exchange columns. The addition of small amount of EDTA can eliminate the influence, but brings serious isobaric interference on boron isotopic analysis by TIMS. Finally, we establish a three-column ion-exchange procedure including the first mixed resin column, the peristaltic pump coupled boron specific resin column, and the second mixed resin column, which ensures the full recovery of boron (about 99%) from tourmaline samples with complex matrices. The positive thermal ionization mass spectrometry (PTIMS)-Cs2BO2+-static double-collection method was established by selecting H3-H4 Faraday cups and optimizing parameters in Zoom Optics (Focus Quad: 15; Dispersion Quad: -85) in a Triton TI mass spectrometer. The determined average 11B/10B value of NIST SRM 951 is 11B/10B=4.05044±0.00012 (2σ, n=8, 1 μg B), which is superior to the dynamic collection method in internal/external precision. A δ11B value of-0.3‰ for NIST SRM 951 through the same pretreatment procedure was obtained, indicating that there was no isotopic fractionation occurred during the extraction procedure. The comparison of boron isotopes in natural samples by TIMS and MC-ICP-MS after chemistry procedure turns out that δ11B values determined by the PTIMS-Cs2BO2+ method are in good agreement with that by MC-ICP-MS.
2012, 40(11): 1661-1667
doi: 10.3724/SP.J.1096.2012.20176
Abstract:
An efficient and accurate analytical method was developed for the simultaneous determination of 20 synthetic food additives, including acesulfame potassium, benzoic acid, sorbic acid, sodium saccharin, tartrazine, amaranthus red, ponceau 4R, caffeine, sunset yellow, aspartame, allure red, brilliant blue, erythrosine, methyl paraben, ethyl paraben, isopropyl paraben, n-propyl paraben, isobutyl paraben, n-butyl paraben and n-heptyl paraben, by high performance liquid chromatography (HPLC) coupled with photodiode array detector(PDA). A C18 stationary phase was used and the mobile phase contained an acetonitrile-methanol (10:90, V/V) mixture and 0.1 mol/L ammonium acetate buffer solution at pH 7.2. Successful separation was obtained for all the compounds within 50 min at 30℃ by using gradient elution. The absorbance of 20 compounds behaved linearly with their concentrations ranged from 0.10 mg/L to 300 mg/L with correlation coefficients more than 0.998. The limits of detection of these compounds were from 0.005 mg/L to 0.110 mg/L. The recoveries were from 91.4% to 100.5% at spiked levels of 10-100 mg/L, The precision (n=6) was range from 0.6% to 4.0%. The method has been used in the determination of 16 food additives in various drinks.
An efficient and accurate analytical method was developed for the simultaneous determination of 20 synthetic food additives, including acesulfame potassium, benzoic acid, sorbic acid, sodium saccharin, tartrazine, amaranthus red, ponceau 4R, caffeine, sunset yellow, aspartame, allure red, brilliant blue, erythrosine, methyl paraben, ethyl paraben, isopropyl paraben, n-propyl paraben, isobutyl paraben, n-butyl paraben and n-heptyl paraben, by high performance liquid chromatography (HPLC) coupled with photodiode array detector(PDA). A C18 stationary phase was used and the mobile phase contained an acetonitrile-methanol (10:90, V/V) mixture and 0.1 mol/L ammonium acetate buffer solution at pH 7.2. Successful separation was obtained for all the compounds within 50 min at 30℃ by using gradient elution. The absorbance of 20 compounds behaved linearly with their concentrations ranged from 0.10 mg/L to 300 mg/L with correlation coefficients more than 0.998. The limits of detection of these compounds were from 0.005 mg/L to 0.110 mg/L. The recoveries were from 91.4% to 100.5% at spiked levels of 10-100 mg/L, The precision (n=6) was range from 0.6% to 4.0%. The method has been used in the determination of 16 food additives in various drinks.
2012, 40(11): 1668-1673
doi: 10.3724/SP.J.1096.2012.20203
Abstract:
A microfluidic chip based circular injection method for bio-samples was presented. The microfluidic chip with an annular peristaltic micropump and electromagnetic microvalves was fabricated using PDMS (polydimethylsiloxane) soft lithography process. The chip was then integrated with an immune probe chip immobilized with rabbit IgG, and realized the circular injection of Goat-anti-rabbit IgG (FITC labeled) solution and sample enrichment. Higher fluorescence intensity was obtained using circular injection than that using static adsorption, under different sample concentrations and 3 min binding time. By increasing the pumping speed from 130 μL/min to 300 μL/min, the immune binding speed with 50 mg/L sample concentration was accelerated evidently, which meant the detection limit at a given time could be lower, but for 200 mg/L sample concentration, the effect was weaker. Compared to the continuous injection mode with about 1.8 mL of sample consumption, only 7 μL sample was needed to realize the coincident results with the circular injection mode.
A microfluidic chip based circular injection method for bio-samples was presented. The microfluidic chip with an annular peristaltic micropump and electromagnetic microvalves was fabricated using PDMS (polydimethylsiloxane) soft lithography process. The chip was then integrated with an immune probe chip immobilized with rabbit IgG, and realized the circular injection of Goat-anti-rabbit IgG (FITC labeled) solution and sample enrichment. Higher fluorescence intensity was obtained using circular injection than that using static adsorption, under different sample concentrations and 3 min binding time. By increasing the pumping speed from 130 μL/min to 300 μL/min, the immune binding speed with 50 mg/L sample concentration was accelerated evidently, which meant the detection limit at a given time could be lower, but for 200 mg/L sample concentration, the effect was weaker. Compared to the continuous injection mode with about 1.8 mL of sample consumption, only 7 μL sample was needed to realize the coincident results with the circular injection mode.
2012, 40(11): 1674-1679
doi: 10.3724/SP.J.1096.2012.20244
Abstract:
A new method was developed for the determination of seven illicit drugs and metabolites in human hair by ultra high performance liquid chromatograph tandem a linear ion trap-orbitrap hybrid instrument at high mass resolution (UHPLC-LTQ-Orbitrap/MS). After being washed and grinded, the hair samples were soaked in pH 9.2 borate buffer with ultrasonic for 90 min. Then the samples were extracted by solid phase extraction (SPE). High resolution mass spectrometry was applied to reduce matrix interference. Full scanning of electrostatic field orbitrap was applied for quantification of drugs. The limits of detection (LOD) of seven illicit drugs and metabolites in human hair were 0.001-0.02 μg/g. The method showed a fairly good linearity over the range of 0.05-50 μg/g (r>0.9975). The spiked recoveries were between 76.1%-109.6%, and the deviation of intra-and inter-day precision was less than 14.9%. The method is simple, high sensitive, and suitable for the determination of illicit drugs in human hair.
A new method was developed for the determination of seven illicit drugs and metabolites in human hair by ultra high performance liquid chromatograph tandem a linear ion trap-orbitrap hybrid instrument at high mass resolution (UHPLC-LTQ-Orbitrap/MS). After being washed and grinded, the hair samples were soaked in pH 9.2 borate buffer with ultrasonic for 90 min. Then the samples were extracted by solid phase extraction (SPE). High resolution mass spectrometry was applied to reduce matrix interference. Full scanning of electrostatic field orbitrap was applied for quantification of drugs. The limits of detection (LOD) of seven illicit drugs and metabolites in human hair were 0.001-0.02 μg/g. The method showed a fairly good linearity over the range of 0.05-50 μg/g (r>0.9975). The spiked recoveries were between 76.1%-109.6%, and the deviation of intra-and inter-day precision was less than 14.9%. The method is simple, high sensitive, and suitable for the determination of illicit drugs in human hair.
2012, 40(11): 1680-1685
doi: 10.3724/SP.J.1096.2011.10225
Abstract:
Room temperature phosphorescence (RTP) property of Mn-doped ZnS quantum dots (QDs) was explored to develop a novel method for selective detection of lead cation. The influence factors such as buffer kinds and their concentration, the concentration of Mn-doped ZnS QDs solution, reaction time and coexisting substances were studied. It was found that under optimized conditions, i.e. 10 mmol/L Tris-HCl buffer at pH 7.4 and 2 min reaction time, the relative RTP intensity of the Mn-doped ZnS QDs was quenched linearly by lead cation in the concentration range from 0.25 to 1000 μmol/L, and the limit of detection was 0.04 μmol/L (8.3 μg Pb/L). This method was also applied to measure lead cation in biosamples using a high-throughput 96 well plate with a wide linear range, simpleness, rapidness, high sensitivity and selectivity, and cost effectiveness. The RTP was quenched linearly by lead cation in human plasma in the concentration range from 5 to 1000 μmol/L, and the limit of detection was 0.48 μmol/L (Pb 99 μg/L), respectively.
Room temperature phosphorescence (RTP) property of Mn-doped ZnS quantum dots (QDs) was explored to develop a novel method for selective detection of lead cation. The influence factors such as buffer kinds and their concentration, the concentration of Mn-doped ZnS QDs solution, reaction time and coexisting substances were studied. It was found that under optimized conditions, i.e. 10 mmol/L Tris-HCl buffer at pH 7.4 and 2 min reaction time, the relative RTP intensity of the Mn-doped ZnS QDs was quenched linearly by lead cation in the concentration range from 0.25 to 1000 μmol/L, and the limit of detection was 0.04 μmol/L (8.3 μg Pb/L). This method was also applied to measure lead cation in biosamples using a high-throughput 96 well plate with a wide linear range, simpleness, rapidness, high sensitivity and selectivity, and cost effectiveness. The RTP was quenched linearly by lead cation in human plasma in the concentration range from 5 to 1000 μmol/L, and the limit of detection was 0.48 μmol/L (Pb 99 μg/L), respectively.
2012, 40(11): 1686-1692
doi: 10.3724/SP.J.1096.2012.20093
Abstract:
A novel and sensitive method was developed and validated for the simultaneous determination of hexythiazox and buprofezin residue in tea, mango and marrow using gas chromatography coupled with tandem mass spectrometry. Target compounds were extracted by acetonitrile followed by dispersive solid phase extraction cleanup. The fragmentation pathway and matrix effect were investigated. Over the concentration in the range of 0.040-4.000 mg/L for buprofezin and 0.025-2.5 mg/L for hexythiazox in different matrix, the correlation coefficients (r) of the calibration curves were above 0.9910, and the limits of detection (LODs) were 0.005 mg/L and 0.010 mg/L for each other. The average recoveries of hexythiazox and buprofezin in different matrix at three spiked concentration levels ranged from 83.6% to 116.9% with relative standard deviations (RSDs) between 2.0% and 15.7% (n=5). The limits of quantitation (LOQs) of hexythiazox and buprofezin, were 0.010 mg/kg in green tea and 0.002 mg/kg in marrow and mango sample. Then, the proposed method was successfully applied to the routine market monitoring of mango and marrow in different regions in China, there was no hexythiazox and buprofezin residue detected in the all of samples (n=120); and it has also been applied to the residue analysis of buprofezin field test samples (n=20) in tea garden, the residues of buprofezin were from not detected to 3.9 mg/kg.
A novel and sensitive method was developed and validated for the simultaneous determination of hexythiazox and buprofezin residue in tea, mango and marrow using gas chromatography coupled with tandem mass spectrometry. Target compounds were extracted by acetonitrile followed by dispersive solid phase extraction cleanup. The fragmentation pathway and matrix effect were investigated. Over the concentration in the range of 0.040-4.000 mg/L for buprofezin and 0.025-2.5 mg/L for hexythiazox in different matrix, the correlation coefficients (r) of the calibration curves were above 0.9910, and the limits of detection (LODs) were 0.005 mg/L and 0.010 mg/L for each other. The average recoveries of hexythiazox and buprofezin in different matrix at three spiked concentration levels ranged from 83.6% to 116.9% with relative standard deviations (RSDs) between 2.0% and 15.7% (n=5). The limits of quantitation (LOQs) of hexythiazox and buprofezin, were 0.010 mg/kg in green tea and 0.002 mg/kg in marrow and mango sample. Then, the proposed method was successfully applied to the routine market monitoring of mango and marrow in different regions in China, there was no hexythiazox and buprofezin residue detected in the all of samples (n=120); and it has also been applied to the residue analysis of buprofezin field test samples (n=20) in tea garden, the residues of buprofezin were from not detected to 3.9 mg/kg.
2012, 40(11): 1693-1697
doi: 10.3724/SP.J.1096.2012.20298
Abstract:
Organophosphorus flame retardants (OPFRs), as their increasing production and consumption, are almost ubiquitous in environmental compartments. In this study, a solid phase extraction (SPE) coupled with gas chromatography-mass spectrometric (SPE-GC-MS) method was developed for the determination of 8 typical OPFRs. The targets in water samples were concentrated by Poly-Sery PSD SPE cartridge, and then eluted by 4 mL ethyl acetate. The OPFRs were qualified and quantified by GC-MS in selective ion scan monitoring method (SIM). Good linearity was observed in the range of 2 to 200 ng/L OPFRs with correlation coefficients varing between 0.9937 and 0.9995. The limits of detection and limits of quantification ranged from 0.006 to 0.850 ng/L and 0.015 to 2.000 ng/L, respectively. Spiked recoveries of pure water and river water samples ranged from 70.3% to 114.3%, with the relative standard deviations less than 15%, except for tri(2-ethylhexyl)phosphate(TEHP). The satisfied recovery of TEHP was achieved when the spiked concentration was less than 50 ng/L. The results showed that the SPE-GC-MS analytical method established was sensitive and accurate for the determination of OPFRs in surface water samples. Then the method was applied to analyze OPFRs in the water collected in Meiliang Bay of Taihu Lake, and it was found that the total concentration of OPFRs was ranging from 1000 to 2700 ng/L.
Organophosphorus flame retardants (OPFRs), as their increasing production and consumption, are almost ubiquitous in environmental compartments. In this study, a solid phase extraction (SPE) coupled with gas chromatography-mass spectrometric (SPE-GC-MS) method was developed for the determination of 8 typical OPFRs. The targets in water samples were concentrated by Poly-Sery PSD SPE cartridge, and then eluted by 4 mL ethyl acetate. The OPFRs were qualified and quantified by GC-MS in selective ion scan monitoring method (SIM). Good linearity was observed in the range of 2 to 200 ng/L OPFRs with correlation coefficients varing between 0.9937 and 0.9995. The limits of detection and limits of quantification ranged from 0.006 to 0.850 ng/L and 0.015 to 2.000 ng/L, respectively. Spiked recoveries of pure water and river water samples ranged from 70.3% to 114.3%, with the relative standard deviations less than 15%, except for tri(2-ethylhexyl)phosphate(TEHP). The satisfied recovery of TEHP was achieved when the spiked concentration was less than 50 ng/L. The results showed that the SPE-GC-MS analytical method established was sensitive and accurate for the determination of OPFRs in surface water samples. Then the method was applied to analyze OPFRs in the water collected in Meiliang Bay of Taihu Lake, and it was found that the total concentration of OPFRs was ranging from 1000 to 2700 ng/L.
2012, 40(11): 1698-1702
doi: 10.3724/SP.J.1096.2012.20361
Abstract:
An analytical method was developed for the simultaneous analysis of 10 kinds of PBDEs, 12 MeO-PBDEs and 9 kinds of HO-PBDEs in zebrafish eggs by liquid-liquid extraction coupled with GC/MS/MS. The conditions of extraction, chromatography and mass spectrometry were optimized. The target compounds were extracted through liquid-liquid extraction and derivatization of HO-PBDEs can be carried out without separation from extraction solution. Thus the pre-treatment time could be shortened and all target compounds could be analyzed simultaneously. Purification was conducted by dry packed acidic silica gel column. All compounds can be eluted with 15mL n-hexane and 15mL of dichloromethane and hexane (1:1, V/V) mixed solvent. Under optimized conditions, 31 compounds had good linearity in concentration range from 4.0 to 500 μg/L, with correlation coefficient (R2) better than 0.9933, recoveries in the range of 71.6%-133.0% with relative standard deviations less than 21.5%, and the method and instrument detection limits varied from 0.09 to 17.0 ng/g. The presented method was applied for maternal transfer study of BDE-47, 6-HO-BDE-47, 6-MeO-BDE-47, 2'-HO-BDE-28 and 2'-MeO-BDE-28 and turned out to be efficient for real sample analysis. After maternal exposure, the five compounds showed different maternal transfer potency in zebrafish, giving new consideration for the exposure assessment of such compounds.
An analytical method was developed for the simultaneous analysis of 10 kinds of PBDEs, 12 MeO-PBDEs and 9 kinds of HO-PBDEs in zebrafish eggs by liquid-liquid extraction coupled with GC/MS/MS. The conditions of extraction, chromatography and mass spectrometry were optimized. The target compounds were extracted through liquid-liquid extraction and derivatization of HO-PBDEs can be carried out without separation from extraction solution. Thus the pre-treatment time could be shortened and all target compounds could be analyzed simultaneously. Purification was conducted by dry packed acidic silica gel column. All compounds can be eluted with 15mL n-hexane and 15mL of dichloromethane and hexane (1:1, V/V) mixed solvent. Under optimized conditions, 31 compounds had good linearity in concentration range from 4.0 to 500 μg/L, with correlation coefficient (R2) better than 0.9933, recoveries in the range of 71.6%-133.0% with relative standard deviations less than 21.5%, and the method and instrument detection limits varied from 0.09 to 17.0 ng/g. The presented method was applied for maternal transfer study of BDE-47, 6-HO-BDE-47, 6-MeO-BDE-47, 2'-HO-BDE-28 and 2'-MeO-BDE-28 and turned out to be efficient for real sample analysis. After maternal exposure, the five compounds showed different maternal transfer potency in zebrafish, giving new consideration for the exposure assessment of such compounds.
2012, 40(11): 1703-1708
doi: 10.3724/SP.J.1096.2012.20213
Abstract:
A method was developed for the determination of trace anions (Cl-, NO3-, PO43- and SO42-) in high pure fluoride reagents by ion chromatography (IC) with column-switching. Ion excluding column IonPac ICE-AS6 was used in the first step to separate the trace anion analytes from the high concentrated fluoride using deionized water as the mobile phase, separated analytes were enriched in the pre-concentration column IonPac TAC-ULP1 at the same time. By using a mixture of 4.5 mmol/L Na2CO3-0.8 mmol/L NaHCO3 as the eluent at a flow rate of 1.2 mL/min, the analytes were eluted from the pre-concentrated column after switching the pre-concentrated column into the analytical system. The separation of the analytes was performed with IonPac AG23 (50 mm × 4 mm) as guard column and IonPac AS23 (250 mm×4 mm) as analytical column, and the detection was performed by suppressed conductivity detector. As a result, the linear ranges of the method for Cl-, NO3-, PO43- and SO42- were 0.02-5.0 mg/L (r=0.9996), 0.02-5.0 mg/L (r=0.9999), 0.05-10.0 mg/L (r=0.9998), 0.02-5.0 mg/L (r=0.9997) respectively. The average recoveries were 92.0%-103.5% with the relative standard deviations (RSD, n=7) less than 3.0%. The detection limits (S/N=3) were 0.2, 0.6, 3.0 and 0.5 mg/kg for Cl-, NO3-, PO43-and SO42-, respectively.
A method was developed for the determination of trace anions (Cl-, NO3-, PO43- and SO42-) in high pure fluoride reagents by ion chromatography (IC) with column-switching. Ion excluding column IonPac ICE-AS6 was used in the first step to separate the trace anion analytes from the high concentrated fluoride using deionized water as the mobile phase, separated analytes were enriched in the pre-concentration column IonPac TAC-ULP1 at the same time. By using a mixture of 4.5 mmol/L Na2CO3-0.8 mmol/L NaHCO3 as the eluent at a flow rate of 1.2 mL/min, the analytes were eluted from the pre-concentrated column after switching the pre-concentrated column into the analytical system. The separation of the analytes was performed with IonPac AG23 (50 mm × 4 mm) as guard column and IonPac AS23 (250 mm×4 mm) as analytical column, and the detection was performed by suppressed conductivity detector. As a result, the linear ranges of the method for Cl-, NO3-, PO43- and SO42- were 0.02-5.0 mg/L (r=0.9996), 0.02-5.0 mg/L (r=0.9999), 0.05-10.0 mg/L (r=0.9998), 0.02-5.0 mg/L (r=0.9997) respectively. The average recoveries were 92.0%-103.5% with the relative standard deviations (RSD, n=7) less than 3.0%. The detection limits (S/N=3) were 0.2, 0.6, 3.0 and 0.5 mg/kg for Cl-, NO3-, PO43-and SO42-, respectively.
2012, 40(11): 1709-1714
doi: 10.3724/SP.J.1096.2012.20139
Abstract:
Klebsiella Oxytoca B12, isolated from diseased Anguilla janponica, was used for rabbit anti-serum preparation by injecting the formalin-inactivated bacteria. The rabbit immunoglobulin (IgG) was purified by SPA affinity column. A microplate sandwich immunoassay for the detection of K. Oxytoca was developed utilizing time-resolved fluoroimmunoassay (TRFIA). Antibodies immobilized on microtiter plates were used to capture the bacteria. The bound antigen-antibody complexes were then detected using the same antibodies labeled with Eu3+ chelates. The effects of antibody concentration, immunoreaction time and dissociation time on assay were studied during assay development. The limit of detection was 5.0×103 cfu/mL and the linear range was 5.0×103-1.0×107 cfu/mL with the correlation coefficients more than 0.99. Cross reaction showed that it had high specificity. The intra-assay and inter-assay standard deviation were 5.6% and 2.3%, respectively. The method was optimized to detect the tissues including gill, kidney, intestine, liver and muscle from infected K. Oxytoca with satisfactory results.
Klebsiella Oxytoca B12, isolated from diseased Anguilla janponica, was used for rabbit anti-serum preparation by injecting the formalin-inactivated bacteria. The rabbit immunoglobulin (IgG) was purified by SPA affinity column. A microplate sandwich immunoassay for the detection of K. Oxytoca was developed utilizing time-resolved fluoroimmunoassay (TRFIA). Antibodies immobilized on microtiter plates were used to capture the bacteria. The bound antigen-antibody complexes were then detected using the same antibodies labeled with Eu3+ chelates. The effects of antibody concentration, immunoreaction time and dissociation time on assay were studied during assay development. The limit of detection was 5.0×103 cfu/mL and the linear range was 5.0×103-1.0×107 cfu/mL with the correlation coefficients more than 0.99. Cross reaction showed that it had high specificity. The intra-assay and inter-assay standard deviation were 5.6% and 2.3%, respectively. The method was optimized to detect the tissues including gill, kidney, intestine, liver and muscle from infected K. Oxytoca with satisfactory results.
2012, 40(11): 1715-1719
doi: 10.3724/SP.J.1096.2012.20110
Abstract:
Under neutral condition, phosphate ions could inhibit the catalytic effect of copper ions on the hydrolysis of rhodamine spirolactam to form fluorescent rhodamine B, resulting in the decrease of fluorescent intensity. Moreover, the inhibitive degree was in proportional to the concentration of phosphate ions, which could be developed for sensing phosphate. In the buffer (pH 7.0) solution, phosphate ions could be determined in the range of 3.0×10-6-4.5×10-5mol/L with the correlation coefficient of 0.9938 and the detection limit of 1.6×10-7 mol/L (3σ). This method was applied to the detection of phosphate in artificial wetlands with the recovery from 93.0% to 108.0% and the RSD lower than 6.0%.
Under neutral condition, phosphate ions could inhibit the catalytic effect of copper ions on the hydrolysis of rhodamine spirolactam to form fluorescent rhodamine B, resulting in the decrease of fluorescent intensity. Moreover, the inhibitive degree was in proportional to the concentration of phosphate ions, which could be developed for sensing phosphate. In the buffer (pH 7.0) solution, phosphate ions could be determined in the range of 3.0×10-6-4.5×10-5mol/L with the correlation coefficient of 0.9938 and the detection limit of 1.6×10-7 mol/L (3σ). This method was applied to the detection of phosphate in artificial wetlands with the recovery from 93.0% to 108.0% and the RSD lower than 6.0%.
2012, 40(11): 1720-1724
doi: 10.3724/SP.J.1096.2012.20218
Abstract:
A selective and sensitive on-line preconcentration procedure was developed for the determination of trace levels of copper(Ⅱ) by flame atomic absorption spectrometry(FAAS). A mini-column packed with a silica gel functionalized with thioacetamide was used for the on-line selective enrichment of copper(Ⅱ) at pH 1.0.The copper(Ⅱ) was eluted with 0.6 mol/L thiourea solution and determined by FAAS. Some important flow injection variables affecting preconcentration were optimized (sample flow rate was 8.0 mL/min, eluent flow rate was 5.0 mL/min and elution time was 60 s). Under the optimum conditions, linear calibration graphs over the concentration ranges of 2.0-100.0 μg/L and 0.5-30.0 μg/L; detection limits of 0.36 and 0.07 μg/L; preconcentration factor of 80 and 170 were obtained for the preconcentration volumes of 10.0 and 50.0 mL of copper(Ⅱ) solutions, respectively. The relative standard deviations for 9 replicate determinations of copper(Ⅱ) were 3.5% and 2.0% at same conditions, respectively. The effect of the presence of various species commonly associated with environmental samples was also investigated. The method has been successfully applied to the selective determination of the trace Copper in standard reference materials GBW07602, GBW08608 with satisfactory results.
A selective and sensitive on-line preconcentration procedure was developed for the determination of trace levels of copper(Ⅱ) by flame atomic absorption spectrometry(FAAS). A mini-column packed with a silica gel functionalized with thioacetamide was used for the on-line selective enrichment of copper(Ⅱ) at pH 1.0.The copper(Ⅱ) was eluted with 0.6 mol/L thiourea solution and determined by FAAS. Some important flow injection variables affecting preconcentration were optimized (sample flow rate was 8.0 mL/min, eluent flow rate was 5.0 mL/min and elution time was 60 s). Under the optimum conditions, linear calibration graphs over the concentration ranges of 2.0-100.0 μg/L and 0.5-30.0 μg/L; detection limits of 0.36 and 0.07 μg/L; preconcentration factor of 80 and 170 were obtained for the preconcentration volumes of 10.0 and 50.0 mL of copper(Ⅱ) solutions, respectively. The relative standard deviations for 9 replicate determinations of copper(Ⅱ) were 3.5% and 2.0% at same conditions, respectively. The effect of the presence of various species commonly associated with environmental samples was also investigated. The method has been successfully applied to the selective determination of the trace Copper in standard reference materials GBW07602, GBW08608 with satisfactory results.
2012, 40(11): 1725-1729
doi: 10.3724/SP.J.1096.2012.20271
Abstract:
In the conventional method of erythrocytes treatment, there was the efflux of pyruvic acid in erythrocytes (PAE) during washing and separation of erythrocytes/leukocytes using the physiological saline. This phenomenon caused the deviation of the measured value of PAE from its real concentration. This research designed a method comprising the steps of employing the erythrocyte lysis buffer to specifically lyse the red blood cells, separating leukocytes and platelets by centrifugation, removing the protein by heating the hemolysate, and detecting PAE using the pyruvate-enzyme fluorescence capillary analysis. The optimized procedures for the blood pretreatment were as follows: at the centrifugal speed of 16000 r/min, the blood sample was centrifuged for 1 min to obtain erythrocytes, after the erythrocytes were lysed by the lysis buffer, the hemolysate was heated for 5 min at 100℃. Through the contrast experiment, it was found that this method was superior to other erythrocyte treatment method. The pyruvate determination method in this research had a good linearity in the range of 10-120 mmol/L, a detection limit of 0.98 mmol/L, and a sensitivity of 5.64 F L/mmol, it was 60 times higher than that of references method. This method offered a relative standard deviation of PAE less than 2.8% (n=11), and a recovery range of 98.3%-104.1%.
In the conventional method of erythrocytes treatment, there was the efflux of pyruvic acid in erythrocytes (PAE) during washing and separation of erythrocytes/leukocytes using the physiological saline. This phenomenon caused the deviation of the measured value of PAE from its real concentration. This research designed a method comprising the steps of employing the erythrocyte lysis buffer to specifically lyse the red blood cells, separating leukocytes and platelets by centrifugation, removing the protein by heating the hemolysate, and detecting PAE using the pyruvate-enzyme fluorescence capillary analysis. The optimized procedures for the blood pretreatment were as follows: at the centrifugal speed of 16000 r/min, the blood sample was centrifuged for 1 min to obtain erythrocytes, after the erythrocytes were lysed by the lysis buffer, the hemolysate was heated for 5 min at 100℃. Through the contrast experiment, it was found that this method was superior to other erythrocyte treatment method. The pyruvate determination method in this research had a good linearity in the range of 10-120 mmol/L, a detection limit of 0.98 mmol/L, and a sensitivity of 5.64 F L/mmol, it was 60 times higher than that of references method. This method offered a relative standard deviation of PAE less than 2.8% (n=11), and a recovery range of 98.3%-104.1%.
2012, 40(11): 1730-1734
doi: 10.3724/SP.J.1096.2012.20123
Abstract:
With the high specific affinitive antibody to uniconazole prepared in our lab, the method of antibody-immobilized direct competitive ELISA was employed to determine uniconazole residue in apple. Under the optimized conditions the antibody of 4 mg/L dissolved in 0.02 mol/L pH7.6 PB was immobilized on microplate,the peroxidase-hapten conjugate was 105 times diluted in the reaction medium of 0.02 mol/L pH 6.8 PBS containing 0.15 mol/L NaCl, the liner concentrations ranged from 1 mg/L to 10-4 mg/L, the half-maximal inhibition (IC50) was 1.31 μg/L with relative standard deviation (RSD) of 8.4%, the IC20 was 0.022 μg/L. The recoveries were 84.6%-101%, 99.6%-117% and 80.8%-92.8% with the RSD of 8.6%, 6.9% and 6.7% at the spiked level of 1.0, 0.1, 0.01 mg/kg in apple respectively. The limit of detection for ELISA was 0.024 μg/kg, and the limit of detection for HPLC-ultraviolet visible detector was 0.25 mg/kg.
With the high specific affinitive antibody to uniconazole prepared in our lab, the method of antibody-immobilized direct competitive ELISA was employed to determine uniconazole residue in apple. Under the optimized conditions the antibody of 4 mg/L dissolved in 0.02 mol/L pH7.6 PB was immobilized on microplate,the peroxidase-hapten conjugate was 105 times diluted in the reaction medium of 0.02 mol/L pH 6.8 PBS containing 0.15 mol/L NaCl, the liner concentrations ranged from 1 mg/L to 10-4 mg/L, the half-maximal inhibition (IC50) was 1.31 μg/L with relative standard deviation (RSD) of 8.4%, the IC20 was 0.022 μg/L. The recoveries were 84.6%-101%, 99.6%-117% and 80.8%-92.8% with the RSD of 8.6%, 6.9% and 6.7% at the spiked level of 1.0, 0.1, 0.01 mg/kg in apple respectively. The limit of detection for ELISA was 0.024 μg/kg, and the limit of detection for HPLC-ultraviolet visible detector was 0.25 mg/kg.
2012, 40(11): 1735-1739
doi: 10.3724/SP.J.1096.2012.20201
Abstract:
Based on monoclonal antibodies with high affinity against fumonisin B1, a direct competitive chemiluminescence enzyme-linked immunosorbent assay (dc-CLEIA) for detection of FB1 in cereal was developed. FB1 artificial antigens were synthesized by the carbodiimide crosslinking methods, and then a hybridoma cell that secreted the antibody selectively identifies FB1 was selected through cell fusion. The monoclonal antibody titer was found as higher as 1.28×106, which was labeled with horse radish peroxidase (HRP) through sodium periodate activation for development of dc-CELIA. A good linearity was achieved over a concentration range of 0.32-8.40 μg/L, the IC50 value and the limit of detection were 1.43 μg/L and 0.13 μg/L, respectively. Meanwhile, the competitive reaction time was only 20 min. The recoveries of FB1 in all tissues were between 100.2%-115.4% and the relative standard deviation was less than 8.7%. The dc-CLEIA was applied in quantification of FB1 elimination in cereal, the results showed good correlations of the results obtained by HPLC and a commercial ELISA kit.
Based on monoclonal antibodies with high affinity against fumonisin B1, a direct competitive chemiluminescence enzyme-linked immunosorbent assay (dc-CLEIA) for detection of FB1 in cereal was developed. FB1 artificial antigens were synthesized by the carbodiimide crosslinking methods, and then a hybridoma cell that secreted the antibody selectively identifies FB1 was selected through cell fusion. The monoclonal antibody titer was found as higher as 1.28×106, which was labeled with horse radish peroxidase (HRP) through sodium periodate activation for development of dc-CELIA. A good linearity was achieved over a concentration range of 0.32-8.40 μg/L, the IC50 value and the limit of detection were 1.43 μg/L and 0.13 μg/L, respectively. Meanwhile, the competitive reaction time was only 20 min. The recoveries of FB1 in all tissues were between 100.2%-115.4% and the relative standard deviation was less than 8.7%. The dc-CLEIA was applied in quantification of FB1 elimination in cereal, the results showed good correlations of the results obtained by HPLC and a commercial ELISA kit.
2012, 40(11): 1740-1746
doi: 10.3724/SP.J.1096.2012.20409
Abstract:
Three-dimensional excitation emission matrix fluorescence spectroscopy (3D-EEMs) was applied to analyze the variation characteristics of dissolved organic matter (DOM) six fractions in landfill leachate during photocatalytic degradation. The results showed that fluorescence spectroscopy of hydrophobic acids (HOA), hydrophobic bases (HOB), hydrophobic neutral traction (HIB), hydrophobic neutral fraction (HON) and hydrophilic neutral fraction (HIN) changed considerably, and that of HIA was relatively steady during photocatalytic process. In general, fluorescence peaks of humic acids-like had the most significant change during photocatalytic treatment process, and disappeared entirely after 60 h treatment, which implied that humic acids-like can be degraded preferentially. In 72 h effluent, VIS fulvic-like, tryptophan-like and tyrosine-like were residual in the fluorescence regions, and the last two were predominant fractions. These results indicated that macromolecular fulvic-like and humic acids-like can be degraded into micro-molecular protein-like matters.
Three-dimensional excitation emission matrix fluorescence spectroscopy (3D-EEMs) was applied to analyze the variation characteristics of dissolved organic matter (DOM) six fractions in landfill leachate during photocatalytic degradation. The results showed that fluorescence spectroscopy of hydrophobic acids (HOA), hydrophobic bases (HOB), hydrophobic neutral traction (HIB), hydrophobic neutral fraction (HON) and hydrophilic neutral fraction (HIN) changed considerably, and that of HIA was relatively steady during photocatalytic process. In general, fluorescence peaks of humic acids-like had the most significant change during photocatalytic treatment process, and disappeared entirely after 60 h treatment, which implied that humic acids-like can be degraded preferentially. In 72 h effluent, VIS fulvic-like, tryptophan-like and tyrosine-like were residual in the fluorescence regions, and the last two were predominant fractions. These results indicated that macromolecular fulvic-like and humic acids-like can be degraded into micro-molecular protein-like matters.
2012, 40(11): 1747-1751
doi: 10.3724/SP.J.1096.2012.20138
Abstract:
A novel method was established for the simultaneous determination of resorcinol and phloroglucinol in environmental water samples by ion chromatography with chemiluminescence detection. Using 50 mmol NaOH solution as eluent, resorcinol and phloroglucinol can be well separated with IonPac AS19 column and determined based on the chemiluminescence reaction of luminol and potassium ferricyanide in an alkaline medium.The optimal CL conditions were 6.0×10-4 mol/L luminol, 0.1 mol/L potassium ferrocyanide and 5.5×10-5 mol/L potassium ferricyanide. The absence of methanol and acetonitrile in mobile phase made the proposed method more sensitive. Under the optimal conditions, the detection limits (LOD) of resorcinol and phloroglucinol were 4.0 μg/L and 4.3 μg/L, respectively. The method showed good linearity within the range of 0.05-1.0 mg/L. The relative standard deviations (RSD) for 0.1 mg/L resorcinol and phloroglucinol standard solutions were 0.9% and 1.1% (n=11). The method has been applied to the determination of resorcinol and phloroglucinol in environmental water samples successfully.
A novel method was established for the simultaneous determination of resorcinol and phloroglucinol in environmental water samples by ion chromatography with chemiluminescence detection. Using 50 mmol NaOH solution as eluent, resorcinol and phloroglucinol can be well separated with IonPac AS19 column and determined based on the chemiluminescence reaction of luminol and potassium ferricyanide in an alkaline medium.The optimal CL conditions were 6.0×10-4 mol/L luminol, 0.1 mol/L potassium ferrocyanide and 5.5×10-5 mol/L potassium ferricyanide. The absence of methanol and acetonitrile in mobile phase made the proposed method more sensitive. Under the optimal conditions, the detection limits (LOD) of resorcinol and phloroglucinol were 4.0 μg/L and 4.3 μg/L, respectively. The method showed good linearity within the range of 0.05-1.0 mg/L. The relative standard deviations (RSD) for 0.1 mg/L resorcinol and phloroglucinol standard solutions were 0.9% and 1.1% (n=11). The method has been applied to the determination of resorcinol and phloroglucinol in environmental water samples successfully.
2012, 40(11): 1752-1757
doi: 10.3724/SP.J.1096.2012.20398
Abstract:
A simple and rapid method, vortex-assisted extraction (VAE) followed by dispersive liquid-liquid microextraction (DLLME) has been developed for the extraction of polycyclic aromatic hydrocarbons (PAHs) in sediment samples prior to analysis by high performance liquid chromatography (HPLC)-fluorescence detection (FLD). Effects of significant parameters, such as type and volume of extraction and disperser solvent, extraction time, salt content and pH value, were optimized. Under the optimum conditions, the limits of detection (LODs) ranged from 2.3 to 6.8 ng/g, the linearity ranged from 10 to 2100 ng/g, coefficients of determinations (R2) ranged from 0.9986 to 0.9994. The average recoveries of PAHs in sediment samples spiking with 3 different concentration levels were 85.2%±4.7%, 85.0%±5.0% and 85.0%±5.1%, respectively, and the relative standard deviations were 5.7%, 6.1% and 5.7%, respectively. The proposed method was successfully applied in analysis of real nature sediment samples. PAHs were detected in all real nature sediment samples collecting from 3 different depths, the average amount in sediment samples were 73.3, 49.8 and 28.3 ng/g, respectively and the average recoveries was 84.8%±4.8%, 83.1%±4.7% and 84.6%±4.6%, respectively.
A simple and rapid method, vortex-assisted extraction (VAE) followed by dispersive liquid-liquid microextraction (DLLME) has been developed for the extraction of polycyclic aromatic hydrocarbons (PAHs) in sediment samples prior to analysis by high performance liquid chromatography (HPLC)-fluorescence detection (FLD). Effects of significant parameters, such as type and volume of extraction and disperser solvent, extraction time, salt content and pH value, were optimized. Under the optimum conditions, the limits of detection (LODs) ranged from 2.3 to 6.8 ng/g, the linearity ranged from 10 to 2100 ng/g, coefficients of determinations (R2) ranged from 0.9986 to 0.9994. The average recoveries of PAHs in sediment samples spiking with 3 different concentration levels were 85.2%±4.7%, 85.0%±5.0% and 85.0%±5.1%, respectively, and the relative standard deviations were 5.7%, 6.1% and 5.7%, respectively. The proposed method was successfully applied in analysis of real nature sediment samples. PAHs were detected in all real nature sediment samples collecting from 3 different depths, the average amount in sediment samples were 73.3, 49.8 and 28.3 ng/g, respectively and the average recoveries was 84.8%±4.8%, 83.1%±4.7% and 84.6%±4.6%, respectively.
2012, 40(11): 1758-1763
doi: 10.3724/SP.J.1096.2012.20523
Abstract:
An enantioselective method was developed for separation and determination of six chiral polychlorinated biphenyls (PCBs) including PCB 91, 95, 136, 149, 176 and 183 in lotus root, stem, leaf and sediment by GC-MS. After optimizations of instrumental parameters for enantiomeric separation and investigations of sample preparations including accelerated solvent extraction (ASE) parameters, extraction solvents and cleanup methods, PCBs enantiomers were extracted from samples by ASE with n-hexane/acetone (1:1, V/V) at 100℃ and 10.3 MPa for 10 min. The extracts were orderly sulphonated by sulfuric acid, purified by Florisil solid phase extraction column, reconstituted with isooctane after being concentrated, and respectively detected by GC-MS with Chirasil-Dex and BGB-172 columns. For all PCBs enantiomers, good linearities were obtained in the concentration range of 0.5-100 μg/L, and recoveries of spiked samples at 0.25, 2.5 and 25 μg/kg levels were 82.8%-117.0% with relative standard deviations (RSD) of 1.5%-13.6%. Limits of detection (LOD) and limits of quantification (LOQ) were 0.01-0.02 μg/kg and 0.025-0.04 μg/kg, respectively. The real samples analysis showed that chiral PCBs were not detected in lotus roots from markets, but higher concentrations were found in lotus root and sediment from contaminated area. The concentrations of PCB 91-2, PCB 95-1 and (+)- PCB 136 in lotus root, stem and leaf were respectively higher than those of their enantiomers, while no significant differences between two enantiomers of PCB 149, 176 and 183.
An enantioselective method was developed for separation and determination of six chiral polychlorinated biphenyls (PCBs) including PCB 91, 95, 136, 149, 176 and 183 in lotus root, stem, leaf and sediment by GC-MS. After optimizations of instrumental parameters for enantiomeric separation and investigations of sample preparations including accelerated solvent extraction (ASE) parameters, extraction solvents and cleanup methods, PCBs enantiomers were extracted from samples by ASE with n-hexane/acetone (1:1, V/V) at 100℃ and 10.3 MPa for 10 min. The extracts were orderly sulphonated by sulfuric acid, purified by Florisil solid phase extraction column, reconstituted with isooctane after being concentrated, and respectively detected by GC-MS with Chirasil-Dex and BGB-172 columns. For all PCBs enantiomers, good linearities were obtained in the concentration range of 0.5-100 μg/L, and recoveries of spiked samples at 0.25, 2.5 and 25 μg/kg levels were 82.8%-117.0% with relative standard deviations (RSD) of 1.5%-13.6%. Limits of detection (LOD) and limits of quantification (LOQ) were 0.01-0.02 μg/kg and 0.025-0.04 μg/kg, respectively. The real samples analysis showed that chiral PCBs were not detected in lotus roots from markets, but higher concentrations were found in lotus root and sediment from contaminated area. The concentrations of PCB 91-2, PCB 95-1 and (+)- PCB 136 in lotus root, stem and leaf were respectively higher than those of their enantiomers, while no significant differences between two enantiomers of PCB 149, 176 and 183.
2012, 40(11): 1764-1771
doi: 10.3724/SP.J.1096.2012.20100
Abstract:
A sensitive multiresidual analytical method for simultaneous analysis of multiresidual fungicides in environmental water samples was developed. The method was based on solid phase extraction (SPE) followed by high performance liquid chromatography tandem mass spectrometry (LC-MS/MS). Qualitative and quantitative detection for the analytes was carried out under the multiple reaction monitoring (MRM) in positive ionization mode after chromatography separation. In this method we have studied the conversion rule, identified the chromatogram retention time of Z-isomer and E-isomer of flumorph and dimethomorph, confirmed their chromatographic behavior by monitoring concentrations of two isomers of them at room temperature under sunlight and optimized parameters that may affect the SPE procedure efficiency: the column type, the wash solvent and the elution solvent. The recoveries of the SPE gave levels ranged from 70.18% to 108.87%, all recoveries were acceptable, with relative standard deviation (RSD) ≤16.7%. The limit of quantification (LOQ, S/N=10) varied between 0.003 and 0.03 μg/L (except for fenhexamid 0.3 μg/L). The developed method was applied for the determination of multiresidual fungicides in 100 tap water samples and 6 environmental samples collected from Liaoning province in China. Total fungicides were not found in tap water samples. Azoxystrobin (0.051 μg/L), metalaxyl (0.217 μg/L) and dimethomorph (Z, E) (0.015 μg/L) were found in Pu river sample, dimethomorph (Z, E) (0.004 μg/L) was found in Hun river sample, the highest concentration level of metalaxyl was 0.217 μg/L in Pu river, the rest of fungicides remained undetected in river samples.
A sensitive multiresidual analytical method for simultaneous analysis of multiresidual fungicides in environmental water samples was developed. The method was based on solid phase extraction (SPE) followed by high performance liquid chromatography tandem mass spectrometry (LC-MS/MS). Qualitative and quantitative detection for the analytes was carried out under the multiple reaction monitoring (MRM) in positive ionization mode after chromatography separation. In this method we have studied the conversion rule, identified the chromatogram retention time of Z-isomer and E-isomer of flumorph and dimethomorph, confirmed their chromatographic behavior by monitoring concentrations of two isomers of them at room temperature under sunlight and optimized parameters that may affect the SPE procedure efficiency: the column type, the wash solvent and the elution solvent. The recoveries of the SPE gave levels ranged from 70.18% to 108.87%, all recoveries were acceptable, with relative standard deviation (RSD) ≤16.7%. The limit of quantification (LOQ, S/N=10) varied between 0.003 and 0.03 μg/L (except for fenhexamid 0.3 μg/L). The developed method was applied for the determination of multiresidual fungicides in 100 tap water samples and 6 environmental samples collected from Liaoning province in China. Total fungicides were not found in tap water samples. Azoxystrobin (0.051 μg/L), metalaxyl (0.217 μg/L) and dimethomorph (Z, E) (0.015 μg/L) were found in Pu river sample, dimethomorph (Z, E) (0.004 μg/L) was found in Hun river sample, the highest concentration level of metalaxyl was 0.217 μg/L in Pu river, the rest of fungicides remained undetected in river samples.
2012, 40(11): 1772-1779
doi: 10.3724/SP.J.1096.2012.20436
Abstract:
Graphene and its derivatives have recently attracted considerable attention because of their vast array of distinct electronic, thermal, mechanical, optical, and electrochemical properties. Thus, this set of compounds has become a research hotspot and a promising area for scientific research. The significantly high carrier mobility, high electrical conductivity, high surface area, ease of functionalization, strong fluorescence quenching, and affinity for biomolecules make graphene and its derivatives suitable in the development of biosensing systems. In our review, we describe the recent applications of graphene and its derivatives to field-effect transistors as well as to electrochemical, piezoelectric, photoluminescence, and electrochemiluminescence biosensing systems.
Graphene and its derivatives have recently attracted considerable attention because of their vast array of distinct electronic, thermal, mechanical, optical, and electrochemical properties. Thus, this set of compounds has become a research hotspot and a promising area for scientific research. The significantly high carrier mobility, high electrical conductivity, high surface area, ease of functionalization, strong fluorescence quenching, and affinity for biomolecules make graphene and its derivatives suitable in the development of biosensing systems. In our review, we describe the recent applications of graphene and its derivatives to field-effect transistors as well as to electrochemical, piezoelectric, photoluminescence, and electrochemiluminescence biosensing systems.
2012, 40(11): 1780-1788
doi: 10.3724/SP.J.1096.2012.20448
Abstract:
Carbohydrate microarray (glyco-chip), is one of modern biotechnologies for monitoring the molecular interactions between carbohydrate ligands and other biomacromolecules. It is characterized by micro-scale, quickness, high sensitivity and high-throughput and is widely applicable in many fields. Its promising R & D areas include, but are not limited to, biology, basic medical research, clinical diagnostics, drug development and bio-material & reagent industry. This article intends to summarize methods that are currently used for the construction of glyco-chips, such as immobilization of either chemically modified or non-modified carbohydrates and procedures of self-assembly for production of three-dimensional glyco-chips. Current challenges and future trends in the R & D of glyco-chips are also discussed.
Carbohydrate microarray (glyco-chip), is one of modern biotechnologies for monitoring the molecular interactions between carbohydrate ligands and other biomacromolecules. It is characterized by micro-scale, quickness, high sensitivity and high-throughput and is widely applicable in many fields. Its promising R & D areas include, but are not limited to, biology, basic medical research, clinical diagnostics, drug development and bio-material & reagent industry. This article intends to summarize methods that are currently used for the construction of glyco-chips, such as immobilization of either chemically modified or non-modified carbohydrates and procedures of self-assembly for production of three-dimensional glyco-chips. Current challenges and future trends in the R & D of glyco-chips are also discussed.
