[Simultaneous detection of lower aliphatic amines and conventional cations in atmospheric PM2.5 particulates by ion chromatography]

Many amine pollutants exist in the atmosphere. Lower aliphatic amines promote the formation and growth of particles into PM2.5, which damages the heart, lungs, and kidneys of the human body. PM2.5, a common atmospheric particulate pollutant with complex compositions, is the main cause of haze weather. Therefore, measuring the contents of lower aliphatic amines and cations in PM2.5 is of great significance for monitoring environmental air quality and protecting human health. This study established a suppressed ion-chromatographic method with conductivity for the simultaneous detection of four lower aliphatic amines (methylamine, dimethylamine, trimethylamine, and ethylamine) and five cations (Na+, N[Formula: see text], and Ca2+ showed high concentrations. The contents of the four lower aliphatic amines were low; however, the ethylamine content in some samples was high. The results indicate that the proposed method meets the quantification requirements for cations and lower aliphatic amines in PM2.5, with simple processing, high sensitivity, and good accuracy. It can quickly and accurately detect a large number of samples and be used to assess the pollution of small particles in the air as well as trace pollution sources to protect human health.

[Simultaneous determination of eight organic amines in desulfurization solution by ion chromatography]

The applications of organic-amine desulfurization have steadily increased owing to its high efficiency, low cost, and low energy consumption. Different proportions of organic amines exert different effects on sulfur dioxide removal. Therefore, the accurate determination of different organic amines in the desulfurization solution is of great importance. The ion-chromatographic method for the detection of organic amines does not require a derivatization step, has simple pretreatment procedures, and allows for the simultaneous determination of many types of organic amines. In this study, a method based on ion chromatography was developed for the simultaneous determination of ethanolamine (MEA), diethylethanolamine (DEEA), n-methyldiethanolamine (MDEA), 2-amino-2-methyl-1-propanol (AMP), hydroxyethylethylenediamine (AEEA), piperazine (PZ), n-hydroxyethylpiperazine (HEPZ), and diethylenetriamine (DETA). The separation efficiency of the eight organic amines in different types of columns, leaching solutions, and column temperatures were compared. The determination was performed using an IonPac CS17 column with column temperature of 35 ℃ and gradient leaching with methyl sulfonic acid (MSA) solution via the inhibition conductance method. Samples of the desulfurization solution were analyzed using ultrapure water filtered through a 0.22 μm nylon microporous filter membrane and an OnGuard Ⅱ RP column; thus, the pretreatment steps are simple. The eight organic amines showed a good linear relationship within a certain concentration range, and the coefficient of determinations (R2) were greater than 0.998. The limits of detection (LODs) and quantification (LOQs) were determined from the mass concentrations of the organic amines corresponding to signal-to-noise ratios (S/N) of 3 and 10, respectively. LODs of 0.02-0.08 mg/L and LOQs of 0.07-0.27 mg/L were determined from a 1.0 μL sample injection. The actual recoveries ranged from 93.0% to 111%, and the relative standard deviations (RSDs, n=5) ranged from 0.31% to 1.2%. The results indicated that the proposed method has good accuracy and precision; thus, it is suitable for the determination of various organic amines in desulfurization solution.

[Applications of ion chromatography for the analysis of Chinese herbal medicine components]

Ion chromatography (IC) is a novel high performance liquid chromatographic technique that is suitable for the separation and analysis of ionic substances in different matrix samples. Since 1975, it has been widely used in many fields, such as the environment, energy, food, and medicine. IC compensates for the separation limitations of traditional gas chromatography and high performance liquid chromatography and can realize the qualitative analysis and quantitative detection of strongly polar components. This chromatographic technique features not only simple operations but also rapid analysis. The sensors used in IC are characterized by high sensitivity and selectivity, and the technique can simultaneously separate and determine multiple components. Several advances in IC instrumentation and chromatographic theories have been developed in recent years. IC can analyze various types of samples, including ions, sugars, amino acids, and organic acids (bases). Chinese herbal medicines are typically characterized by highly complex chemical compositions and may contain carbohydrates, proteins, alkaloids, and other active components. They also contain toxic residues such as sulfur dioxide, which may be produced during the processing of medicinal materials. Therefore, the analysis and elucidation of the precise chemical constituents of Chinese herbal medicines present key problems that must be resolved in modern Chinese herbal medicine research. In this context, IC has become an important method for analyzing and identifying the complex components of Chinese herbal medicines because this method is suitable for detecting a single active ingredients among complex components. This paper introduces the different types and principles of IC as well as research progress in this technique. As the applications of IC-based methods in pharmaceutical science, cell biology, and microbiology increase, further development is necessary to expand the applications of this technique. The development of innovative techniques has enabled IC technologies to achieve higher analytical sensitivity, better selectivity, and wider application. The components of Chinese herbal medicines can be divided into endogenous and exogenous components according to their source: endogenous components include glycosides, amino acids, and organic acids, while exogenous components include toxic residues such as sulfur dioxide. Next, the applications of IC to the complex components of Chinese herbal medicines in recent decades are summarized. The most commonly used IC technologies and methods include ion exchange chromatography and conductivity detection. The advantages of IC for the analysis of alkaloids have been demonstrated. This method exhibits better characteristics than traditional analytical methods. However, the applications of IC for the speciation analysis of inorganic anions are limited. Moreover, few reports on the direct application of the technique for the determination of the main active substances in Chinese herbal medicines, including flavonoids, phenylpropanoids, and steroids, have been reported. Finally, this paper reviews new IC technologies and their application progress in Chinese herbal medicine, focusing on their prospects for the effective separation and analysis of complex components. In particular, we discuss the available sample (on-line) pretreatment technologies and explore possible technologies for the selective and efficient enrichment and separation of different components. Next, we assess innovative research on solid-phase materials that can improve the separation effect and analytical sensitivity of IC. We also describe the features of multidimensional chromatography, which combines the advantages of various chromatographic techniques. This review provides a theoretical reference for the further development of IC technology for the analysis of the complex chemical components of Chinese herbal medicines.

[Determination of organic acids and anions in exhaled breath by condensation collection-ion chromatography]

A non-invasive condensation collection-ion chromatography method was established for the determination of organic acids and anions including lactic acid, formic acid, acetic acid, pyruvic acid, chloride, nitrate, nitrite, and sulfate in the exhaled breath of humans. The breath exhaled was condensed and collected using a home-made exhaled breath condensation equipment. This equipment included a disposable mouthpiece as a blow-off port, one-way valve and flow meter, cold trap, disposable condensate collection tube placed in the cold trap, and gas outlet. A standard sampling procedure was used. Before collection, the collection temperature and sampling volume were set on the instrument control panel, and sampling was started when the cold-trap temperature dropped to the set value, while maintaining the balance. Subjects were required to gargle with pure water before sampling. During the sampling process, the subjects were required to inhale deeply until the lungs were full of gas and then exhale evenly through the air outlet. When the set volume was collected, the instrument made a prompt sound; then, the collection was immediately ended, the expiration time was recorded, and the average collection flow was calculated according to the expiration time and sampling volume. After collection, the disposable condensation collection tube was immediately taken out, sealed, and stored in the refrigerator at -20 ℃ away from light, and immediately used for further testing. The organic acids and anions in exhaled breath condensation (EBC) were filtered through a 0.22 μm membrane filter before injection and detected by ion chromatography with conductivity detection. Factors such as collection temperature and collection flow rate during condensation collection were optimized. The optimal cooling temperature was set at -15 ℃, and the optimal exhaled breath flow rate was set at 15 L/min. The mobile phase consisted of a mixture of sodium carbonate (1.5 mmol/L) and sodium bicarbonate (3 mmol/L). The flow rate was 0.8 mL/min, and the injection volume was 100 μL. An IC-SA3 column (250 mm×4.0 mm) was used, and the temperature was set at 45 ℃. An ICDS-40A electrodialysis suppressor was used, and the current was set at 150 mA. The linear ranges of the eight organic acids and anions were 0.1-10.0 mg/L; their correlation coefficients (r) were ≥0.9993. The limits of detection (LODs) for the eight organic acids and anions were 0.0017-0.0150 mg/L based on a signal-to-noise ratio of 3, and the limits of quantification (LOQs) were 0.0057-0.0500 mg/L based on a signal-to-noise ratio of 10. The intra-day precisions were 5.06%-6.33% (n=5), and the inter-day precisions were 5.37%-7.50% (n=5). This method was used to detect organic acids and anions in the exhaled breath of five healthy subjects. The contents of organic acids and anions in the exhaled breath were calculated. The content of lactic acid was relatively high, at 1.13-42.3 ng/L, and the contents of other seven organic acids and anions were 0.18-11.0 ng/L. During a 10 km-long run, the majority of organic acids and anions in the exhaled breath of five subjects first increased and then decreased. However, due to abnormal metabolism, the content changes of lactic acid, acetic acid, pyruvic acid and chloride in one subject were obviously different from others during exercise, showing a continuous rise. This method has the advantages of involving a simple sampling process and exhibiting good precision, few side effects, and no obvious discomfort or risk to the subjects. This study provides experimental ideas and a theoretical basis for future research on human metabolites.

[Determination of trace anions in battery-grade lithium carbonate by double-inhibition on-line matrix-removal ion chromatography]

A method was developed for the determination of trace anions in battery-grade lithium carbonate. In this method, lithium carbonate was dissolved in ultrapure water with ultrasound assistance, and its matrix was removed using an on-line matrix-removal method. In the matrix-removal process, the sample was first passed through an ADRS600(4 mm) suppressor (suppressor current, 150 mA; external water flow rate, 2 mL/min). Hydrogen and lithium ions were then completely exchanged via the ion-exchange membrane in the suppressor, converting the lithium carbonate into carbonic acid. The carbonic acid entered the waste-liquid channel in the form of carbon dioxide through a CRD 200(4 mm) carbonate removal device to remove the lithium carbonate matrix. Finally, the target anions were automatically enriched on an IonPac UTAC-LP2 concentration column (35 mm×3 mm) and automatically transferred to a chromatographic system using valve-switching technology. The chromatographic system featured an IonPac AG18 column (50 mm×2 mm) as the protection column and an IonPac AS18 column (250 mm×2 mm) as the analytical column. The column temperature was 30 ℃, gradient elution was performed using KOH solution as the eluent, and the pump flow rate was 0.30 mL/min. An ADRS600(2 mm) suppressor, suppressor current of 25 mA, injection volume of 250 μL, and conductance detector were also used. The results showed good linear relationships (r≥ 0.999) for F-, Cl-, [Formula: see text] in their respective concentration ranges. The limits of detection (LODs) and quantification (LOQs) were 0.05-0.88 and 0.15-2.92 μg/L, respectively. Lithium carbonate samples were tested six consecutive times, and the relative standard deviations (RSDs) of the peak areas of each ion were less than 0.73%. The same lithium carbonate samples were injected after 0, 2, 4, 8, 12, 18, and 24 h, and the RSD of the peak areas of each ion was less than 0.96%. The average recoveries ranged from 93.3% to 99.3%, and the RSDs (n=6) of samples spiked at three levels were in the range of 0.97%-3.45%. The proposed method has a low method limit of quantification of only 0.5 mg/kg for each ion analyzed and is capable of the simultaneous analysis of multiple ions. Thus, it is suitable for the detection of trace anions in battery-grade lithium carbonate.

[Simultaneous determination of six nitroaromatic compounds and three anions in environmental matrices using a liquid chromatography-ion chromatography coupled system]

Nitroaromatic compounds are used extensively in various fields such as dyes, pesticides, spices, pharmaceuticals, and explosives. However, the residual raw materials of these compounds accumulate in the environment and pose serious risks to human health. Chronic exposure to low concentrations of nitroaromatic compounds can cause anemia, cancer, and organ damage. Currently, Fenton oxidation and natural bioremediation are the processes most often used to eliminate nitroaromatic compounds from environmental water and soil. According to previous research, the presence of inorganic anions such as chloride, nitrite, and nitrate ions in the environmental matrix exerts an inhibitory effect on the biodegradation of nitroaromatic compounds. Furthermore, high nitrate levels in drinking water can lead to the production of nitrosamine carcinogens, which affect ecological safety and human health, in water bodies. Thus, the simultaneous determination of nitroaromatic compounds and chloride, nitrite, and nitrate ions in environmental soil and water matrices is critical for selecting appropriate nitroaromatic compound degradation methods and monitoring surface water quality. Traditional detection methods require two sample pretreatment steps and two instrumental analytical techniques to determine nitroaromatic compounds and inorganic anions in environmental matrices; moreover, these methods are time consuming, labor intensive, and error prone. Therefore, in this study, a method that combines high performance liquid chromatography (HPLC) and ion chromatography (IC) was developed to simultaneously detect nitroaromatic compounds and anions in environmental matrices. In this method, sample enrichment was achieved through bulk injection and enrichment column collection, which greatly simplified the pretreatment process. The HPLC instrument was connected to the IC instrument using two six-way valves and an enrichment column. The system operation can be divided into four stages: (A) sample loading to the quantitative ring, (B) separation of nitroaromatic compounds and anions, (C) enrichment of anions in an AG20 column, and (D) simultaneous determination of nitroaromatic compounds and anions by HPLC and IC, respectively. The time of the anions flowing out of the C18 column was determined by directly connecting the C18 column to a conductivity detector. Based on the retention times of the anions, the switching time of the six-way valve was optimized to ensure that the anions completely entered the IC column, thereby ensuring the accuracy of the method. During the chromatographic analysis stage, nitroaromatic compounds were separated and analyzed by HPLC system with a mobile phase composed of potassium phosphate buffer (pH 7.0) and acetonitrile (60∶40, v/v) at a flow rate of 1.0 mL/min; in the IC system, the anions were separated and analyzed using a 20 mmol/L sodium hydroxide aqueous solution as the mobile phase under a suppression current of 50 mA. Both anions and nitroaromatic compounds exhibited strong linear correlations within certain concentration ranges, with correlation coefficients greater than 0.993. The recoveries of the nitroaromatic compounds and anions ranged from 88.20% to 105.38% at three spiked levels, with relative standard deviations ranging from 2.0% to 11.5%. The contents of six nitroaromatic compounds and three anions in five surface water and five soil samples were determined using the developed method. Although no nitroaromatic compounds were detected in these samples, the three anions were detected at contents ranging from 0.41 to 55.3 mg/L in surface water samples, and 0.56 to 30.2 mg/kg in soil samples. Methodological validation and actual sample detection demonstrated that the proposed method has a high degree of automation, simple operation, good repeatability, high accuracy, wide applicability, and high sensitivity. Thus, this method is suitable for the rapid determination of chloride, nitrite, nitrate ions and nitroaromatic compounds in soil and water and can be extended to the simultaneous determination of inorganic ions and organic matters in other samples.

[Determination of five water-soluble anions in solid and liquid aerosols by ion chromatography with a filter membrane and condensation collection]

Water-soluble ions are important components of solid and liquid aerosols. The ions have a significant impact on the physical and chemical properties of the aerosols and air quality. Thus, determining the concentrations of water-soluble ions in solid and liquid aerosols has far-reaching significance for mitigating pollution and protecting the atmospheric environment. In this study, a technology combining membrane filtration, condensation, and ion chromatography has been established to collect solid aerosols and liquid aerosols and to measure the amount of five water-soluble anions (Cl-, F-, NO3-, NO2-, and SO42-) in these aerosols. First, a solid particle filter was used to collect the solid aerosol, and the condensation collection method was used to collect the liquid aerosol. The solid aerosol was collected in the solid particle filter in the form of solid particles, and the liquid aerosol was collected in the cold trap in the form of a condensate. Next, the amount of water-soluble anions in the solid aerosols and liquid aerosols was detected by ion chromatography using Dionex IonPac AS11-HC-4 μm as the analytical column. The chromatographic separation conditions were as follows: flow rate, 1 mL/min; column temperature, 30 ℃; potassium hydroxide (KOH) concentration of the eluent, 1 to 25 mol/L (linear increase) within 0-40 min; and injection volume, 100 μL. The ions were separated effectively within 40 min. The five anions showed good linear relationships in the range of 0.1-10 mg/L (correlation coefficients ranged from 0.9992 to 0.9997) and the detection limits were 0.02-0.04 mg/L. Finally, the sample collection conditions (sampling time, sampling temperature, and sampling flow rate) for the five water-soluble anions in the solid aerosols and liquid aerosols were optimized, and 2 h, -13 ℃, 1.0 L/min were chosen.Under the optimized conditions, the amounts of the five anions in the solid and liquid aerosols of the actual samples were detected. The mass concentrations of F-, Cl-, NO2-, NO3-, and SO42- ions in the liquid aerosol of the actual sample were 5.7402 μg/m3, 1.1599 μg/m3, 3.3233 μg/m3, 2.4861 μg/m3, and 0.9745 μg/m3, respectively. The mass concentrations of F-, Cl-, NO2-, NO3-, and SO42- ions in the solid aerosol of the actual sample were 14.1037 μg/m3, 5.0398 μg/m3, 9.3052 μg/m3, 8.4528 μg/m3, and 5.6314 μg/m3, respectively. The method can be applied to the detection of actual atmospheric ions detection. In addition, the collection and analysis methods are suitable for exploring the collection and analysis conditions of other ions.

Soluble Salts Quantitative Characterization and Thermodynamic Modeling on Roman Bricks to Assess the Origin of Their Formation

The environmental weathering and the formation of efflorescences on the brick walls are studied at the "Casa di Diana" Mithraeum at Ostia Antica archaeological site. Previous studies on subsoil, bedrock, hydrological systems and environmental conditions, and new ion chromatography analysis combined with ECOS-RUNSALT and Medusa-Hydra thermodynamic modelling software, had allowed us to identify the subsoil contamination related to soluble salts. The atmospheric acidic gases, CO2 and SO2, are determined as the main salt weathering species. A dry deposition after a subsequent hydration action from the shallow freshwater aquifer that reaches up to 1 m on the walls is identified as the mechanism of salt formation. An evaluation of potential sources such as the nearby Fiumicino airport, CO2-rich gases inputs from fumaroles and CO2 inputs was also debated. The risk level of contamination the surfaces of the materials should be considered mildly/very polluted with a medium/high risk of hygroscopic moisture due to the high concentration of sulphates.

[Preparation and characterization of open tubular ion chromatographic columns]

In recent years, significant progress has been made in the area of open tubular ion chromatography (OTIC). In particular, gradient OTIC has been realized through the development of hydroxide eluent-compatible OTIC columns. This review covers the preparation and characterization of different OTIC columns, ranging from the historic silica-based columns to the newly emerging polymer-based open tubular (OT) columns. The preparation of various OTIC stationary phases, from grafted to latex agglomerated and monolayer to multilayer phases, has been briefly introduced. The characterization of electrostatic latex agglomerated OTIC columns has been extensively discussed, e. g. fluorescent ion displacement chromatography, frontal displacement chromatography, and frontal reaction chromatography have been used to measure the capacities of OT columns, and the results are compared with the theoretical calculation values. The variable α_iex, defined as the number of ion-exchange equivalents per unit surface area, is used as an indicator of the capacity of OT columns, to enable a straightforward comparison between OT columns having different inner diameters (i.d.). The newly introduced column capacity parameter, γ_iex, defined as the stationary phase capacity per unit liquid volume present, is used to investigate the relationship between packed and OT columns when using the same stationary phase. Methods for improving the column efficiency, such as decreasing the column diameter and/or increasing the column temperature, are presented. In addition, determination of the functionalization uniformity along an OT column by (a) separately measuring the capacities of two halves of the column, (b) measuring the retention factors for several ions in successive 10 cm segments of the column in multiple injections, and (c) measuring the retention variance of a single ion in different segments of the column from a single injection, is discussed.

[A polymer resin surface polymerization-based hydroxide-selective anion exchange stationary phase]

A polystyrene-divinylbenzene (PS-DVB) microspheres-based hydroxide-selective anion exchange stationary phase is described. This stationary phase is obtained by the surface polymerization of an allyl glycidyl ether (AGE) and the pendant vinyl groups onto the surface of PS-DVB, followed by open-ring of the epoxy groups using an alkylol amine (abbreviated as P@A-M). Both alkylol amines were compared in terms of separation performance of the stationary phase. Scanning electron microscopy, infrared spectroscopy, and elemental analyses were carried out to characterize the stationary phase. The results indicated that the quaternary amine group was successfully introduced onto the surface of the PS-DVB microspheres, and that there was no obvious change in the physicochemical properties of the resin during the surface polymerization reaction. The P@A-M phase showed high hydroxide-selectivity and good separation performance (resolution>1.5) as well as high running stability (relative standard deviation of retention times<1.13%). The utility of the P@A-M phase was demonstrated by using it for the determination of inorganic anions in the tea.

[Simultaneous determination of twenty amino acids and six carbohydrates in soy sauce by ion chromatography with integrated pulsed amperometric detection]

A method of gradient elution ion chromatography with integrated pulsed amperometric detection for simultaneous determination of twenty amino acids and six carbohydrates in soy sauce was established. The effects of column temperature, pH value of solution, and standing time were studied, and then the suitable gradient elution conditions were found for the determination. In the conditions that the flow rate is 0.25 mL/min, pH value of solution is in the range of 5.2-6.7, temperature of column is 35℃, the linear relationships of the 26 components are good and the correlation coefficients are not less than 0.995. Except glutamine, leucine, isoleucine and methionine, the limits of detection (S/N=3) of the other 22 components are less than 0.03 mg/L. The recoveries of the 26 components in soy sauce are 84.2%-109% at the spiked levels of 0.20, 0.50, 2.00 mg/L, and the relative standard deviations (RSDs) are in the range of 2.7%-7.8%. The method is efficient, easy, sensitive, and accurate for simultaneous determination of amino acids and carbohydrates in soy sauce, and can provide an effective research technique for adulterated soy sauce.

[Determination of seven monosaccharides in aloe polysaccharide using ion chromatography with pulsed amperometric detector]

Aloe polysaccharide was extracted by water extraction and ethanol precipitation. It was hydrolyzed by trifluoroacetic acid, eluted by a sodium hydroxide gradient on a Dionex CarboPac PA10 column, and detected using a pulsed amperometric detector. This method was used to determine the fucose, rhamnose, arabinose, galactose, glucose, mannose, and xylose in aloe polysaccharide. The results showed that the correlation coefficients (R²) of all the seven target compounds were more than 0.997 in the linear range, and the limits of detection were between 0.007 mg/L and 0.024 mg/L. The recoveries were in the range 97.5%-102.5% with the relative standard deviations in the range 0.1%-4.8%. The method is simple, rapid, sensitive, and accurate for the determination of the monosaccharide content and the constitution of aloe polysaccharides.

[Preparation and characterization of a latex-agglomerated anion exchange chromatographic stationary phase]

Allyl glycidyl ether (AGE) was selected as the copolymerization monomer to prepare a copolymer latex-agglomerated anion exchange chromatography stationary phase for ion chromatography (IC). First, allyl glycidyl ether-styrene (AGE-ST) copolymer latex was prepared by the saponification emulsion polymerization method. It was then quaternized by reacting alternatively with methylamine (MA) and 1,4-butanedioldiglycidyl ether (BDDGE) and agglomerated on the surface of sulfonated polystyrene-divinylbenzene (PS-DVB) microspheres to obtain a copolymer latex-agglomerated anion exchange chromatography stationary phase. The stationary phase was characterized by scanning electron microscopy (SEM), FT-IR and elemental analysis (EA). It was found that the diameters of the PS-DVB microsphere and AGE-ST copolymer latex were about 6 μm and 300 nm, respectively. The quaternized AGE-ST copolymer latex was successfully agglomerated on the surface of PS-DVB microspheres and the nitrogen content increased as quaternization time was increased. The chromatographic properties were evaluated by separating conventional anions and organic acids. The results showed that the quaternized AGE-ST copolymer latex-agglomerated PS-DVB anion exchange column exhibited good separation properties toward anions. Therefore, based on the good pH toleration and reaction activity of the newly developed stationary phase, it was concluded that using AGE as a monomer was a good choice.

[Simultaneous determination of nine typical anions in fire explosive residues by ion chromatography]

A novel method was developed for the simultaneous determination of nine typical anions (Cl^-, NO₂^-, ClO₃^-, NO₃^-, CO₃^2-, SO₄^2-, S₂O₃^2-, SCN^-and ClO₄^-) in explosive residues by ion chromatography (IC). A high capacity anion-exchange IonPac AS20 column (250 mm×4 mm) was used for the separation of the nine anions with gradient elution of KOH. The injection volume was 20 μL, the column temperature was 40℃, and the flow rate was 1.20 mL/min. Inhibitory conductivity detections were adopted in the determinations. Good linearities were found for all the nine anions in their respective ranges. The correlation coefficients were greater than 0.999. The method was applied to the determination of the inorganic ions in explosive residues. The average recovery of the nine ions ranged from 92.5% to 101.3%. The relative standard deviations of the nine anions ranged from 1.86% to 2.79% (n=6). The method is simple, quick, selective and sensitive and can meet the requirement of the analysis.

[Determination of organic acids in 1, 2-butylene oxide products by valve switch-ion chromatography]

A novel analytical method was developed for the determination of organic acids (formic acid, acetic acid and propionic acid) in 1, 2-butylene oxide (1, 2-BO) products by valve switch-ion chromatography (IC).The samples were diluted in ethanol, and then were eluted from a concentrator column (IonPac TAC-ULP1) to an analytical column (IonPac AS11).The extracts were detected by a suppressed conductivity detector.Formic acid, acetic acid and propionic acid were separated well.Good linear relationships for the three organic acids were obtained.The spiked recoveries of the three organic acids in the samples were in the range of 92.5%-111.8%.The relative standard deviations (RSDs) were less than 5.6%(n=3).The limits of detection (LODs, S/N=3) of the formic acid, acetic acid and propionic acid were 0.60-4.80 μg/L.The method is simple, rapid, and accurate, and is suitable for the determination of the organic acids in an insoluble organic system.

[Research progress of pyrolysis combined with ion chromatography]

Ion chromatography (IC) is widely used in the anions and cations analysis for its rapid detection and high sensitivity. With the increasing requirement of detecting organic of samples, developing a suitable pretreatment method is important. Pyrolysis apparatus can be operated automatically and easily with high sensitivity and good repeatability. In the paper, the basic principles and types of burners are introduced. The pyrolysis combined with ion chromatography (pyrolysis-IC) are applied in biology, petroleum, coal, materials, environment and other organic samples. The further development of pyrolysis-IC are also introduced.