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2017 Volume 80 Issue 3
2017, 80(3): 219-227
Abstract:
Colloidal photonic crystals (PhCs) are periodically arranged monodisperse nanoparticles and have photonic band gaps (PBGs). Light with certain wavelength or frequencies located in the PBG is prohibited from propagating. Because of this special property, the fabrication and application of colloidal PhCs have attracted increasing interests of researchers. However, the angle dependence is disadvantageous for the construction of some optical materials and devices in which wide viewing angles are desired. Recently, a series of colloidal PhC materials with spherical macroscopic morphology have been created. Because of their spherical symmetry, the PBGs of spherical colloidal PhCs are independent of rotation under illumination of the surface at a fixed incident angle of the light, broadening the perspective of their applications. Because microfluidics has been used for the generation of the droplet templates, the development of spherical colloidal PhCs has progressed significantly. These new strategies not only ensure monodispersity, but also increase the structural and functional diversity of the PhC beads (PCBs). These novel PCBs provide a bridge between PhCs materials and biomedical applications such as barcodes, label-free detection, cell culture and drug delivery, and this also leads PCBs to far-ranging real-world applications. In this review, we present the research progress in PCBs, including their design, preparation and potential applications. Future developments of the PCB materials are also envisioned.
Colloidal photonic crystals (PhCs) are periodically arranged monodisperse nanoparticles and have photonic band gaps (PBGs). Light with certain wavelength or frequencies located in the PBG is prohibited from propagating. Because of this special property, the fabrication and application of colloidal PhCs have attracted increasing interests of researchers. However, the angle dependence is disadvantageous for the construction of some optical materials and devices in which wide viewing angles are desired. Recently, a series of colloidal PhC materials with spherical macroscopic morphology have been created. Because of their spherical symmetry, the PBGs of spherical colloidal PhCs are independent of rotation under illumination of the surface at a fixed incident angle of the light, broadening the perspective of their applications. Because microfluidics has been used for the generation of the droplet templates, the development of spherical colloidal PhCs has progressed significantly. These new strategies not only ensure monodispersity, but also increase the structural and functional diversity of the PhC beads (PCBs). These novel PCBs provide a bridge between PhCs materials and biomedical applications such as barcodes, label-free detection, cell culture and drug delivery, and this also leads PCBs to far-ranging real-world applications. In this review, we present the research progress in PCBs, including their design, preparation and potential applications. Future developments of the PCB materials are also envisioned.
2017, 80(3): 228-235
Abstract:
Layered double hydroxides (LDHs) possess various unique properties such as flexible tenability, uniform distribution of different metal cations in the metal layer, facile exchangeability of intercalated anions and topological transformation characteristics, which makes them to be used as ideal photocatalysts, catalyst supports and precursors. As one kind of novel multifunctional materials, LDH-based photocatalysts have been widely investigated in environmental remediation, energy reservation, industrial catalysis, biomedicine synthesis. However, choosing the feasible path to further optimize the performance of LDH-based photocatalysts to achieve efficient use of solar energy, high conversion efficiency and selectivity of photocatalytic reaction still remains a great challenge. In this paper, the preparation methods of LDH-based photocatalysts are classified into four types including brucite-like sheet construction, guest-intercalation sensitization, de-lamination-assembly and nanocomposite hybrid according to the structure characteristics and the mode of introducing active components. The influence of the preparation methods on photocatalytic performance of LDH-based photocatalysts are introduced and discussed in details. The latest research progress and possible photocatalytic mechanism over LDH-based photocatalysts are reviewed. Finally, the prospects for the development and application of LDH-based photocatalysts are also discussed.
Layered double hydroxides (LDHs) possess various unique properties such as flexible tenability, uniform distribution of different metal cations in the metal layer, facile exchangeability of intercalated anions and topological transformation characteristics, which makes them to be used as ideal photocatalysts, catalyst supports and precursors. As one kind of novel multifunctional materials, LDH-based photocatalysts have been widely investigated in environmental remediation, energy reservation, industrial catalysis, biomedicine synthesis. However, choosing the feasible path to further optimize the performance of LDH-based photocatalysts to achieve efficient use of solar energy, high conversion efficiency and selectivity of photocatalytic reaction still remains a great challenge. In this paper, the preparation methods of LDH-based photocatalysts are classified into four types including brucite-like sheet construction, guest-intercalation sensitization, de-lamination-assembly and nanocomposite hybrid according to the structure characteristics and the mode of introducing active components. The influence of the preparation methods on photocatalytic performance of LDH-based photocatalysts are introduced and discussed in details. The latest research progress and possible photocatalytic mechanism over LDH-based photocatalysts are reviewed. Finally, the prospects for the development and application of LDH-based photocatalysts are also discussed.
2017, 80(3): 236-240, 245
Abstract:
Graphene have good application prospect in nano-electronic devices for its unique normalize electronic valence bond structure. Raman spectroscopy, as a sensitive and convenient technology, has been used for characterizing the structures and properties of graphene successfully. This paper mainly introduces the Raman spectra research on graphene with different doping state or deposited on different substrates. Although the G band and 2D band of Raman spectra has deviation in different degree on various substrates, by observing Raman spectroscopies of graphene on indium tin oxide, sapphire, and glass substrate, the conclusion that the intensity of 2D band can determine the layer of graphene is still applicable. Doping can change the charged state of graphene and make graphene show hole type (p) or electronic (n) doped features. The doping type of graphene can be described qualitatively, as well as the carrier concentration of graphene can be quantitatively determined by analyzing the changes of graphene Raman spectroscopy.
Graphene have good application prospect in nano-electronic devices for its unique normalize electronic valence bond structure. Raman spectroscopy, as a sensitive and convenient technology, has been used for characterizing the structures and properties of graphene successfully. This paper mainly introduces the Raman spectra research on graphene with different doping state or deposited on different substrates. Although the G band and 2D band of Raman spectra has deviation in different degree on various substrates, by observing Raman spectroscopies of graphene on indium tin oxide, sapphire, and glass substrate, the conclusion that the intensity of 2D band can determine the layer of graphene is still applicable. Doping can change the charged state of graphene and make graphene show hole type (p) or electronic (n) doped features. The doping type of graphene can be described qualitatively, as well as the carrier concentration of graphene can be quantitatively determined by analyzing the changes of graphene Raman spectroscopy.
2017, 80(3): 241-245
Abstract:
Heavy metal pollution has become one of the most serious environmental problems today, and removal of heavy metals is the main approach to control heavy metal pollution. Sodium alginate (SA) has many advantages, such as non-toxic, stable nature, low cost, strong gelation ability, film forming ability and complexation ability. It has been widely used as an adsorption material or an immobilized carrier in the removal of heavy metals. This paper focuses on the application of SA gel bead, SA composite film, SA nano composite material, SA molecular imprinted polymer and SA immobilized carrier for the removal of heavy metals. And the development prospects of SA for the removal of heavy metals are also presented.
Heavy metal pollution has become one of the most serious environmental problems today, and removal of heavy metals is the main approach to control heavy metal pollution. Sodium alginate (SA) has many advantages, such as non-toxic, stable nature, low cost, strong gelation ability, film forming ability and complexation ability. It has been widely used as an adsorption material or an immobilized carrier in the removal of heavy metals. This paper focuses on the application of SA gel bead, SA composite film, SA nano composite material, SA molecular imprinted polymer and SA immobilized carrier for the removal of heavy metals. And the development prospects of SA for the removal of heavy metals are also presented.
2017, 80(3): 246-250
Abstract:
Diazo compounds are an important class of carbene precursors, widely used in organic synthesis towards different kinds of functional organic molecules. As one of the most important diazo compounds, diazophosphonates possess some special reaction types and reaction properties. Because of organic phosphorous compounds exhibit extensive bioactivities and pharmaceutic activities, the research of diazophosphonates has attracted lots of attentions of scientists. In this paper, the recent development in the synthese and applications of diazophosphonates are summarized.
Diazo compounds are an important class of carbene precursors, widely used in organic synthesis towards different kinds of functional organic molecules. As one of the most important diazo compounds, diazophosphonates possess some special reaction types and reaction properties. Because of organic phosphorous compounds exhibit extensive bioactivities and pharmaceutic activities, the research of diazophosphonates has attracted lots of attentions of scientists. In this paper, the recent development in the synthese and applications of diazophosphonates are summarized.
2017, 80(3): 251-259
Abstract:
Levoglucosan is a potential source of sugar, it can be hydrolyzed into glucose and then used for microbial fermentation, or be directly metabolized through levoglucosan kinase or levoglucosan dehydrogenase in some fungi and bacteria. It showed a good application prospect in the fermentation field. In addition, levoglucosan can also be used as a carbon source to produce bio-ethanol, succinic acid and so on. At present, biomass pyrolysis is the common-use preparation method of levoglucosan. However, this method has the disadvantages of high energy consumption, low yield and difficult to extract the product. In order to improve the yield of levoglucosan, we should strive to develop a method of decomposing cellulose in solvent system. Future researches should focus on the development new processes, new methods, and new strains for microbial metabolism of levoglucosan, which could lay the groundwork for the efficient use of levoglucosan.
Levoglucosan is a potential source of sugar, it can be hydrolyzed into glucose and then used for microbial fermentation, or be directly metabolized through levoglucosan kinase or levoglucosan dehydrogenase in some fungi and bacteria. It showed a good application prospect in the fermentation field. In addition, levoglucosan can also be used as a carbon source to produce bio-ethanol, succinic acid and so on. At present, biomass pyrolysis is the common-use preparation method of levoglucosan. However, this method has the disadvantages of high energy consumption, low yield and difficult to extract the product. In order to improve the yield of levoglucosan, we should strive to develop a method of decomposing cellulose in solvent system. Future researches should focus on the development new processes, new methods, and new strains for microbial metabolism of levoglucosan, which could lay the groundwork for the efficient use of levoglucosan.
2017, 80(3): 260-265
Abstract:
Membrane biofouling has still been a major problem in membrane bioreactor (MBR) for wastewater treatment. Recently, the quorum quenching technology based on quorum sensing might been an innovative and effective strategy for controlling membrane biofouling. And thus, the recognition and analysis for the signal molecules would play a key role in the application of quorum quenching in dealing with membrane biofouling, which will provide a better understanding of the mechanism of quorum quenching technology in MBR. This paper clarified the main N-acyl homoserine lactones (AHLs) and summarized analytical methods in terms of qualitative and quantitative perspectives, respectively. The mechanism of quorum sensing and AHLs in activated sludge was introduced in details. Further, the qualitative and quantitative analysis methods of AHLs were summarized, and finally, the applications of recognition and analytical technology with respect to AHLs were proposed in MBR.
Membrane biofouling has still been a major problem in membrane bioreactor (MBR) for wastewater treatment. Recently, the quorum quenching technology based on quorum sensing might been an innovative and effective strategy for controlling membrane biofouling. And thus, the recognition and analysis for the signal molecules would play a key role in the application of quorum quenching in dealing with membrane biofouling, which will provide a better understanding of the mechanism of quorum quenching technology in MBR. This paper clarified the main N-acyl homoserine lactones (AHLs) and summarized analytical methods in terms of qualitative and quantitative perspectives, respectively. The mechanism of quorum sensing and AHLs in activated sludge was introduced in details. Further, the qualitative and quantitative analysis methods of AHLs were summarized, and finally, the applications of recognition and analytical technology with respect to AHLs were proposed in MBR.
2017, 80(3): 266-272, 287
Abstract:
Nitrous oxide (N2O) is a significant greenhouse gas and can be produced and emitted from the biological nitrogen removal processes in the wastewater treatment plant (WWTPs). Along with the enhancement of amount and degree of wastewater treatment, the emission of N2O will increase accordingly. The establishments of mathematical models for N2O emissions from the biological nitrogen removal processes in WWTPs have important theoretical and practical significance on the thorough investigations on the mechanisms of N2O production and the development of N2O reduction strategies. The present paper summarized the principals of various biological nitrogen removal processes and systematically elaborated the production mechanisms of N2O and the types, establishment methods and applications of mathematical models simulating N2O emissions. Furthermore, conclusions were achieved based on the research status, and perspectives on future research directions were presented to gain a better modeling of N2O emissions and to provide supports for the reduction of N2O emission, the optimization of the biological nitrogen removal processes and the sustainable development of WWTPs.
Nitrous oxide (N2O) is a significant greenhouse gas and can be produced and emitted from the biological nitrogen removal processes in the wastewater treatment plant (WWTPs). Along with the enhancement of amount and degree of wastewater treatment, the emission of N2O will increase accordingly. The establishments of mathematical models for N2O emissions from the biological nitrogen removal processes in WWTPs have important theoretical and practical significance on the thorough investigations on the mechanisms of N2O production and the development of N2O reduction strategies. The present paper summarized the principals of various biological nitrogen removal processes and systematically elaborated the production mechanisms of N2O and the types, establishment methods and applications of mathematical models simulating N2O emissions. Furthermore, conclusions were achieved based on the research status, and perspectives on future research directions were presented to gain a better modeling of N2O emissions and to provide supports for the reduction of N2O emission, the optimization of the biological nitrogen removal processes and the sustainable development of WWTPs.
2017, 80(3): 273-277
Abstract:
Histidine-diphenylalanine (HisFF) tripeptide gelator was synthesized by chemical modification of the well-assembled diphenylalanine (FF) with histidine through solid phase peptide synthesis method. The precise structure and purity of synthetized HisFF molecule were determined by mass spectrometry (MS) and 1H NMR. The morphology and structures of the HisFF aggregates were observed using TEM and SEM. The strength of HisFF gelated in toluene, chloroform and ethyl acetate were different, and the TEM images showed that the fiber strength and aggregation form also affect the gel stability. HisFF molecule could be assembled into a variety of nanostructures in several different solvents or through different assembly methods. For example, HisFF can be assembled into nanoparticles, nanotubes and helical nanofibers in acetone, respectively, methanol and ethyl acetate. And when it was first dissolved in HFIP then diluted by these solvents, nanofibers with different diameter can be obtained.
Histidine-diphenylalanine (HisFF) tripeptide gelator was synthesized by chemical modification of the well-assembled diphenylalanine (FF) with histidine through solid phase peptide synthesis method. The precise structure and purity of synthetized HisFF molecule were determined by mass spectrometry (MS) and 1H NMR. The morphology and structures of the HisFF aggregates were observed using TEM and SEM. The strength of HisFF gelated in toluene, chloroform and ethyl acetate were different, and the TEM images showed that the fiber strength and aggregation form also affect the gel stability. HisFF molecule could be assembled into a variety of nanostructures in several different solvents or through different assembly methods. For example, HisFF can be assembled into nanoparticles, nanotubes and helical nanofibers in acetone, respectively, methanol and ethyl acetate. And when it was first dissolved in HFIP then diluted by these solvents, nanofibers with different diameter can be obtained.
2017, 80(3): 278-282
Abstract:
Lignin as an abundant natural renewable resource is the ideal feedstock for the production of liquid transportation fuels. In this work a method for the production of liquid transportation fuels from lignin was studied. First, lignin monomer model was oxidized to obtain aromatic aldehyde under the catalysis of K-OMS-2. The lignin dimer model (α-O-4 structure lignin dimer) was oxidized and depolymerized to obtain the aromatic aldehyde in 65% yield. Meanwhile, by oxidizing alkali lignin, vanillin, p-hydroxybenzaldehyde and other aromatic aldehyde compounds can be detected from the product. Then, the length of the carbon chain was increased by Claisen-Schmidt condensation reaction of aromatic aldehydes and acetone. Finally, high-grade saturated alkane fuel was obtained by hydrogenation of aromatic hydrocarbons.
Lignin as an abundant natural renewable resource is the ideal feedstock for the production of liquid transportation fuels. In this work a method for the production of liquid transportation fuels from lignin was studied. First, lignin monomer model was oxidized to obtain aromatic aldehyde under the catalysis of K-OMS-2. The lignin dimer model (α-O-4 structure lignin dimer) was oxidized and depolymerized to obtain the aromatic aldehyde in 65% yield. Meanwhile, by oxidizing alkali lignin, vanillin, p-hydroxybenzaldehyde and other aromatic aldehyde compounds can be detected from the product. Then, the length of the carbon chain was increased by Claisen-Schmidt condensation reaction of aromatic aldehydes and acetone. Finally, high-grade saturated alkane fuel was obtained by hydrogenation of aromatic hydrocarbons.
Preparation of Rh/Co Bimetallic Nanoparticles and Their Catalytic Activities for Hydrogen Generation
2017, 80(3): 283-287
Abstract:
A series of Rh/Co bimetallic nanoparticles (BNPs) were synthesized by co-reduction method using ISOBAM-104 as protective reagent. UV-Vis, TEM and HRTEM were used for characterization of the structure and composition of the prepared nanoparticles. The results showed that Rh/Co BNPs are alloy structure, and the particle size of as-prepared BNPs is less than 6.0 nm. The catalytic activities of the prepared Rh/Co BNPs are higher than that of Rh or Co monometallic nanoparticles, and Rh20Co80 BNPs possesses the highest TOF of 12880 mol-H2·h-1·mol-Rh-1.
A series of Rh/Co bimetallic nanoparticles (BNPs) were synthesized by co-reduction method using ISOBAM-104 as protective reagent. UV-Vis, TEM and HRTEM were used for characterization of the structure and composition of the prepared nanoparticles. The results showed that Rh/Co BNPs are alloy structure, and the particle size of as-prepared BNPs is less than 6.0 nm. The catalytic activities of the prepared Rh/Co BNPs are higher than that of Rh or Co monometallic nanoparticles, and Rh20Co80 BNPs possesses the highest TOF of 12880 mol-H2·h-1·mol-Rh-1.
2017, 80(3): 288-292
Abstract:
TiO2 doped with iron (Fe-TiO2) that prepared by sol-gel method were loaded on the disc surface of spinning disc reactor for the degradation of phenol-containing wastewater. Fe-TiO2 photocatalyst were characterized using X-ray diffraction, Raman spectrum, scanning electron microscopy, and UV-Vis diffuse reflectance spectroscopy. Two factors that affect the degradation efficiency such as doping amount and calcination temperature were investigated. The results showed that some of Ti4+ inside the TiO2 lattice internal was replaced by Fe3+, resulted in increasing internal crystal defects, broadening light response range, and thus improved the photocatalytic activity of nanometer photocatalyst. The degradation effect of Fe-TiO2 is the best for phenol-containing wastewater when doping amount is 0.5% and calcination temperature is 600℃. The phenol degradation rate for 1L of phenol solution can reach 75% after circulation processing for 2 h, more than 20% higher than that of pure TiO2.
TiO2 doped with iron (Fe-TiO2) that prepared by sol-gel method were loaded on the disc surface of spinning disc reactor for the degradation of phenol-containing wastewater. Fe-TiO2 photocatalyst were characterized using X-ray diffraction, Raman spectrum, scanning electron microscopy, and UV-Vis diffuse reflectance spectroscopy. Two factors that affect the degradation efficiency such as doping amount and calcination temperature were investigated. The results showed that some of Ti4+ inside the TiO2 lattice internal was replaced by Fe3+, resulted in increasing internal crystal defects, broadening light response range, and thus improved the photocatalytic activity of nanometer photocatalyst. The degradation effect of Fe-TiO2 is the best for phenol-containing wastewater when doping amount is 0.5% and calcination temperature is 600℃. The phenol degradation rate for 1L of phenol solution can reach 75% after circulation processing for 2 h, more than 20% higher than that of pure TiO2.
2017, 80(3): 293-297
Abstract:
The molecularly imprinted polymer (MIP) had been synthesized using ofloxacin as the template molecule and the modified ash microspheres as carrier by surface molecular imprinting technology. Binding properties and structure of MIP were investigated by ultraviolet spectroscopy and static method respectively. The results demonstrated that the synthesized MIP possess specific recognition selectivity and excellent binding affinity for ofloxacin. Compared with the surface imprinted material with silica gel as carrier, the prepared molecularly imprinted material had the characteristics of high adsorption capacity and favorable imprinted effect. The separation and enrichment effect of MIP as solid phase extraction (SPE) materials were better than that of C18. The SPE coupled with UPLC was used for analysis of ofloxacin in actual samples. The recoveries of the developed method were in the range from 82.0% to 96.7%, and the RSD was less than 5.5%. The results showed that the method could be used for the separation and enrichment of ofloxacin in chicken products.
The molecularly imprinted polymer (MIP) had been synthesized using ofloxacin as the template molecule and the modified ash microspheres as carrier by surface molecular imprinting technology. Binding properties and structure of MIP were investigated by ultraviolet spectroscopy and static method respectively. The results demonstrated that the synthesized MIP possess specific recognition selectivity and excellent binding affinity for ofloxacin. Compared with the surface imprinted material with silica gel as carrier, the prepared molecularly imprinted material had the characteristics of high adsorption capacity and favorable imprinted effect. The separation and enrichment effect of MIP as solid phase extraction (SPE) materials were better than that of C18. The SPE coupled with UPLC was used for analysis of ofloxacin in actual samples. The recoveries of the developed method were in the range from 82.0% to 96.7%, and the RSD was less than 5.5%. The results showed that the method could be used for the separation and enrichment of ofloxacin in chicken products.
2017, 80(3): 298-303
Abstract:
Pectin extracted from the sunflower head (SFP) was tested as a corrosion inhibitor for carbon steel in 1mol/L HCl and 0.5mol/L H2SO4 solutions, respectively. The anticorrosive activity and adsorption behavior of SFP were investigated using weight loss measurements, polarization curve and electrochemical impedance spectroscopy (EIS) methods. The results showed that inhibition efficiency increased with increasing inhibitor concentration, and decreased with increasing temperature. The Langmuir isotherm provided the best description for adsorption behavior of SFP in HCl solution, while Temkin isotherm for adsorption behavior of SFP in H2SO4 solution. Potentiodynamic polarization study revealed that SFP was a mix-typed inhibitor. The results of this study showed that SFP is an eco-friendly, efficient corrosion inhibitor for carbon steel, and its corrosion inhibition performance in HCl solution is better than that in H2SO4 solution due to the synergistic effect of Cl-.
Pectin extracted from the sunflower head (SFP) was tested as a corrosion inhibitor for carbon steel in 1mol/L HCl and 0.5mol/L H2SO4 solutions, respectively. The anticorrosive activity and adsorption behavior of SFP were investigated using weight loss measurements, polarization curve and electrochemical impedance spectroscopy (EIS) methods. The results showed that inhibition efficiency increased with increasing inhibitor concentration, and decreased with increasing temperature. The Langmuir isotherm provided the best description for adsorption behavior of SFP in HCl solution, while Temkin isotherm for adsorption behavior of SFP in H2SO4 solution. Potentiodynamic polarization study revealed that SFP was a mix-typed inhibitor. The results of this study showed that SFP is an eco-friendly, efficient corrosion inhibitor for carbon steel, and its corrosion inhibition performance in HCl solution is better than that in H2SO4 solution due to the synergistic effect of Cl-.
2017, 80(3): 304-306
Abstract:
1, 2-Distearoyl-glycero-3-phosphoethanolamine (DSPE) was synthesized with glycerol-1, 2-distearate, phosphorus oxychloride and 2-aminoethanol as starting materials. Subsequently, reaction of DSPE with N, N'-carbonyldiimidazole (CDI) and mPEG2000 gave the target compound mPEG2000-DSPE, which was characterized by IR analysis, 1H NMR spectroscopy and mass spectrometry.
1, 2-Distearoyl-glycero-3-phosphoethanolamine (DSPE) was synthesized with glycerol-1, 2-distearate, phosphorus oxychloride and 2-aminoethanol as starting materials. Subsequently, reaction of DSPE with N, N'-carbonyldiimidazole (CDI) and mPEG2000 gave the target compound mPEG2000-DSPE, which was characterized by IR analysis, 1H NMR spectroscopy and mass spectrometry.
2017, 80(3): 307-311
Abstract:
Titration error is a key concept in the course of analytical chemistry. In traditional textbooks, titration error is defined with concentrations of both titrant and analyte. The definition via concentration is not suitable for calculation, so a number of formulae are derived from it and used practically. The formula-oriented strategy is simple, but fails to provide a universal way to calculate various types of titration error, which in turn burdens students with annoying memorization. Another flaw of the strategy is its incapability in complex problems, because the formula is either unavailable or too complicated. In this paper, the definition via volume was proposed to replace the one via concentration. The volumes in the definition are those of the titrant added at the end point and the stoichiometric point, respectively. The definition via volume was proven to be equivalent to the one via concentration, and has notable advantages over the latter, such as free from derived formulae and universal. It was also discussed that the Ringbom formula cannot be applied to complicated titrations, so it is not a universal approach to the calculation of titration error as some researches claimed.
Titration error is a key concept in the course of analytical chemistry. In traditional textbooks, titration error is defined with concentrations of both titrant and analyte. The definition via concentration is not suitable for calculation, so a number of formulae are derived from it and used practically. The formula-oriented strategy is simple, but fails to provide a universal way to calculate various types of titration error, which in turn burdens students with annoying memorization. Another flaw of the strategy is its incapability in complex problems, because the formula is either unavailable or too complicated. In this paper, the definition via volume was proposed to replace the one via concentration. The volumes in the definition are those of the titrant added at the end point and the stoichiometric point, respectively. The definition via volume was proven to be equivalent to the one via concentration, and has notable advantages over the latter, such as free from derived formulae and universal. It was also discussed that the Ringbom formula cannot be applied to complicated titrations, so it is not a universal approach to the calculation of titration error as some researches claimed.
