Determination of perchlorate in drinking water by ion chromatography using macrocycle-based concentration and separation methods

Macrocycle-based ion chromatography provides a convenient, reliable method for the determination of perchlorate ion, which is currently of great interest to the environmental community. This study shows that effective perchlorate determinations can be made using standard conductimetric detection by combining an 18-crown-6-based mobile phase with an underivatized reversed-phase mobile phase ion chromatography (MPIC) column. One unique feature of this method is the flexibility in column capacity that is achieved through simple variations in eluent concentrations of 18-crown-6 and KOH, facilitating the separation of target analyte anions such as perchlorate. Using a standard anion exchange column as concentrator makes possible the determination of perchlorate as low as 0.2 ug/L in low ionic strength matrices. Determination of perchlorate at the sub-ug/L level in pure water and in spiked local city hard water samples with high background ion concentrations can be achieved this way. However, like other IC techniques, this method is challenged to achieve analyses at the ug/L level in the demanding high ionic strength matrix described by the United States Environmental Protection Agency (EPA) (1,000 mg/L chloride, sulfate and carbonate). We approached this challenge by use of the Cryptand C1 concentrator column, provided by Dionex Corporation, to effectively preconcentrate perchlorate while reducing background ion concentrations in the high ionic strength matrix. The retention characteristics of the concentrator column were studied in order to maximize its effectiveness for perchlorate determinations. The method makes possible the determination of perchlorate at the 5 ug/L level in the highest ionic strength matrix described by the EPA.     

阀切换-离子色谱法测定1,2-环氧丁烷产品中有机酸

建立了阀切换-离子色谱法测定1,2-环氧丁烷（1,2-BO）产品中有机酸（甲酸、乙酸和丙酸）的方法。样品经乙醇稀释后,通过阀切换技术,有机酸被IonPac TAC-ULP1捕集柱捕集,然后进入IonPac AS11分析柱分离,并由电导检测器检测。结果表明：甲酸、乙酸和丙酸均能实现较好地分离,在各自的范围内其色谱峰面积呈现良好的线性关系。实际样品的加标回收率为92.5%~111.8%,相对标准偏差小于5.6%（n=3）,检出限为0.60~4.80 μg/L。该方法具有前处理简单、快速、准确等特点,适用于不溶于水的有机体系中有机酸的分析。     

混酸消解-毛细管气相色谱法测定生物样品中痕量有机氯化物

本文提出了一种新的生物样品前处理方法,与开管毛细管气相色谱法相结合,可以快速、灵敏、准确地测定生物样品中多种有机氯化物。已用于小白鼠脑、肝、肾样品的测定,结果令人满意。     

Determination of passive-sampled sulphur dioxide in ambient air as sulphate ion by flow injection analysis with an in-line reaction column

A modified FIA method was developed for the determination of sulphur dioxide (SO(2)) in ambient air collected by a passive sampler. SO(2) was oxidized by hydrogen peroxide and determined as sulphate ion in solution. Barium-dimethylsulfoazo-III complex was used as spectrophotometric reagent. A BaSO(4)-immobilized in-line reaction column was introduced into the flow system to increase the sensitivity and reproducibility. An in-line cation exchange column was used to eliminate triethanolamine, which was used as the absorbent reagent in the passive sampler. Sulphate ions can be analyzed in the range of 0.08-10.00 mg l(-1) with the R.S.D. less than 1.6% at the rate of 15 samples h(-1). It was satisfactory to apply this method to the analysis of sulphur dioxide in ambient air and the results agreed with those obtained by ion chromatography.     

多次高温裂解、富集-离子色谱法检测己内酰胺中的痕量氯

建立了多次高温裂解、富集-离子色谱检测己内酰胺(CPL)中痕量氯的分析方法。CPL样品在富氧环境下经3次高温(800℃)裂解后,痕量有机氯转化为氯气或氯化氢气体,经5 mL 10 mmol/L的NaOH溶液吸收、富集,然后转化为氯离子,在阴离子抑制电导检测模式下进行离子色谱分析,检测其中氯离子(Cl-)的含量。在优化的条件下,Cl-在0.05~1.0 mg/L范围内呈良好线性,相关系数为0.999 7,方法检出限为0.37μg/g。对0.8 mg/L的Cl-标准溶液连续进样7次,其保留时间、峰面积、峰高的RSD分别为0.04%、0.24%和0.20%;分别对CPL样品进行处理和检测,得到痕量氯含量的RSD为1.52%(n=4);Cl-标准溶液的转化率为93.3%~104.0%,CPL样品的加标回收率为95.3%~113.1%。该方法操作简单、前处理条件可控、重复性好、检出限低,可满足实际样品中痕量氯的检测。     

High resolution capillary GC–MS analysis of low molecular weight organic compounds in municipal wastewater

High resolution capillary gas chromatography–mass spectrometry has been used in combination with various sample preparation methods to analyze a wide range of low molecular weight organic contaminants in municipal wastewaters. Volatile organic compounds were extracted using a purge and trap concentrator connected directly to a wide bore DB-624 capillary column. Because of the high organic load in wastewater samples, this method was preferred to the more sensitive closed loop stripping technique which suffered from competition effects and insufficient adsorbent capacity. Volatile and semi-volatile base/neutral compounds and acids were extracted with dichloromethane at pH 11 and pH 2, respectively, or were recovered using a simultaneous distillation-extraction procedure. Acidic compounds were subsequently derivatized using diazomethane methylation. Both fractions were separated with a 30m DB-5ms capillary column. Specific ionic substances (LAS, NTA, EDTA) were isolated by solid-phase extraction then derivatized with diazomethane (LAS) or acetyl chloride in n-butanol (NTA, EDTA) before GC–MS analysis. This array of techniques enabled the identification of more than 150 organic contaminants in the influent of a municipal wastewater treatment plant in northern suburban Paris. The individual concentrations of these contaminants ranged from < 0.1 μg/l to 5.7 mg/l.     

微波辅助提取-气相色谱法同时测定中草药中有机磷和氨基甲酸酯农药残留

建立了中草药中有机磷和氨基甲酸酯类农药同时检测的气相色谱分析新方法.中药材试样依据正交实验的优化条件,用正己烷-丙酮(1∶4,V∶V)混合提取剂进行微波辅助提取,经弗罗里硅土和中性氧化铝混合层析柱净化后,采用HP-5毛细管柱分离,氮磷检测器同时检测中草药中15种有机磷和6种氨基甲酸酯类农药残留量.21种农药在0.01～1.0 mg/L的浓度范围内线性良好,线性相关系数为0.9950～1.000,检出限为0.002～0.01 mg/L.在0.05、0.2、0.5 mg/kg三个添加水平的平均回收率分别为75.11%～128.57%、75.85%～120.71%和76.43%～117.25%,相对标准偏差分别为 3.10%～10.58%、5.27%～9.94%和4.03%～9.03%.方法用于中草药中有机磷和氨基甲酸酯类农药残留的同时检测,结果良好.     

Determination of chlorine and bromine in rocks by alkaline fusion with ion chromatography detection

This study describes the use of alkaline fusion by sodium peroxide to dissolve chlorine and bromine in rocks to produce a solution which, with appropriate pre-treatment, is suitable for analysis by ion chromatography. Results are given for a selection of sedimentary and igneous rocks. The accuracy of the fusion method is evaluated by analysis of Geological Survey of Japan reference materials. Additionally, a spike recovery test is performed to show that the fusion process is quantitative for chlorine and bromine. The results for chlorine are in the range 58–3860 mg kg⁻¹ and show good agreement both with results obtained by pyrohydrolysis with flow injection colorimetric detection and results obtained by aqueous leaching of the samples with ion chromatography detection. Results for bromine are in the range <3–4.5 mg kg⁻¹. Because of the relatively few data obtained in this study and the relative paucity of published data for reference materials, an assessment of the accuracy of the fusion method for bromine is more difficult. The limits of detection for this method are 36 and 3 mg kg⁻¹ for chlorine and bromine, respectively.     

Development of a liquid chromatography tandem mass spectrometry method for simultaneous determination of eight adulterants in slimming functional foods

A method for simultaneous determination of eight adulterants including two appetite suppressants, two energy expenditure-enhancing drugs, one diuretic and three cathartics in slimming functional foods by high performance liquid chromatography with electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/MS) was established. After samples were ultrasonically extracted with 70% (v/v) methanol aqueous solution and centrifuged, the components of ephedrine, norpseudoephedrine, fenfluramine, sibutramine, clopamide, emodin, rhein, and chrysophanol in sample solution were separated by a Hypersil Gold column (2.1 mm × 150 mm, 5 μm) using a programmed gradient elution. A mobile phase consisting of 0.02% (v/v) formic acid-ammonium formate buffer solution (pH=3.50) and methanol was used for elution with a flow rate set at 250 μL/min and column temperature of 25 °C. Qualitative determination was based on characteristic ion pairs and retention time of the targeted compounds using SRM (selective reaction monitoring) mode. Clenbuterol and ibuprofen were internal standards in positive and negative ionization mode, respectively. The internal standard curves were used for quantification measurement. The average recoveries of three different concentrations were from 80.2% to 94.5%. The limits of detection (LODs) were from 0.03 to 0.66 mg/kg (except chrysophanol 1.6 mg/kg). The linear dynamic range covered from 1 to 500 μg/L (except chrysophanol 50-5000 μg/L) for the twelve samples analyzed. Adulterants in four different kinds of slimming functional foods were determined by this developed method, and satisfactory results were obtained. These experimental results showed that, adulteration of sibutramine or/and fenfluramine were the major adulterating components with contents varying from 6.1 to 1.3×10(3) mg/kg and 1.9 to 9.7×10(3) mg/kg, respectively. In addition, three cathartic compounds were detected in six of those tested samples, and ephedrine, norpseudoephedrine and clopamide were not detected in all samples.     

在线基体消除-离子色谱法测定墨水染料中的氯及硫酸盐

建立了一种在线基体消除的方法,采用离子色谱法测定了墨水染料中的氯和硫酸盐。样品经溶解、稀释后直接进样,在纯水的输送下依次经过DIONEX OnGuard Ⅱ P和IonPac NG1柱,在线实现了墨水样品中染料和疏水性干扰基体的去除,死时间流出的待测阴离子浓缩于阴离子交换柱IonPac AG11-HC。浓缩柱经阀切换进入离子色谱系统,以4.5 mmol/L Na2CO3-0.8 mmol/L NaHCO3作为淋洗液,流速1.2 mL/min,待测离子经IonPac AS23（4 mm×250 mm）分析柱分离,采用DIONEX DS6电导检测器检测,外标法定量。Cl－和SO2-4的线性范围分别为0.05~5.0、0.1~10.0 mg/L,相关系数分别为0.999 8和 0.999 7,加标回收率为94%~103%,相对标准偏差（n=11）小于1.0%,检出限（S/N=3）分别为0.02、0.05 mg/L。该方法用于墨水染料中氯和硫酸盐的测定,结果满意。     

Determination of residual chlorine by derivatisation with 2,6-dimethylphenol and gas chromatographic separation

Residual chlorine in aqueous solution is converted to 4-chloro-2,6-dimethylphenol, which is extracted into hexane and determined by gas chromatography. Relative standard deviations (n = 5) are 0.36–1.1% for chlorine concentrations of 8.6–0.01 mg l^-1 and chlorine recoveries are 99.2–101%. In the presence of dichromate (30 mg l^-1), relative standard deviations (n = 5) are 1.19–2.71% for chlorine concentrations of 9.3–0.1 mg l^-1. Oxidants and coloured solutes do not interfere.     

气相色谱法同时测定粮食中14种有机磷残留量

建立了气相色谱法同时测定粮食中14种有机磷农药残留的方法。样品经乙腈溶解,高速匀浆,振荡提取,离心浓缩定容,气相色谱外标法定性定量。敌敌畏等14种有机磷农药在DB-1701毛细管柱上得到了很好的分离,在浓度为0.05～2.00mg/L范围内线性关系良好,相关系数r为0.99～1.00,最低检出限为0.01～0.08mg/kg;当添加水平为0.100、0.500、1.000mg/kg 时,回收率为71.2%～113.1% ,相对标准偏差为2.2%～6.9%。方法简单、快速、准确、灵敏,适用于一般检验机构的日常检验需要。     

The determination of organochlorine pesticides and polychlorinated biphenyls by combustion tube decomposition and molecular emission cavity analysis

The determination of microgram quantities of chlorine in polychlorinated biphenyls and organochlorine insecticides by molecular emission cavity analysis is described. Samples either pure, in admixture or mixed with sand were decomposed at 900 ± 50°C in a quartz combustion tube in a humidified oxygen atmosphere. The products of decomposition were bubbled through water or 1% ammonia and 4-μl aliquots of the solution obtained were injected into a stainless steel indium-lined cavity and heated in a nitrogen/hydrogen flame. The chlorine was quantified by comparing the intensity of the InCl emission at 360 nm with that obtained from hydrochloric acid standards. The effect of potential interferences such as alkali and alkaline earth metals, nitrogen, phosphorus, sulphur, carbon aluminium and iron were studied. Except for the alkali and alkaline earth elements, the recoveries of the compounds burned were not affected. Where the elements interfered, methods for eliminating the interferences are described. The chlorine recovery was usually >90%.     

Differentiation of the halogen content of peat samples using ion chromatography after combustion (TX/TOX-IC)

The proposed method for the differential AOX analysis of water samples was tested for its applicability to differentiate the halogen content of peat samples. For determination of the total and the total organic-bound chlorine, bromine and iodine, peat samples were combusted, and the combustion gases trapped and analyzed by ion chromatography (TX/TOX-IC). The total and the organically bound chlorine, bromine and iodine, respectively, can be determined by two-fold analysis with deviations of around 10%. With respect to chlorine more than a double determination could be required. The limit of quantification is 20 mg kg(-1) for chlorine, 2 mg kg(-1) for bromine and 1 mg kg(-1) for iodine, if 25 mg of peat is combusted. The most crucial step of the analysis is the inorganic halogen removal, which is necessary if the organically bound fraction is determined. However, there are some uncertainties about the complete removal of the inorganic halides from the solid samples. Thus, the values of the organically bound fraction have to be discussed as maximal concentrations. Nevertheless, we suggest that the applied method can be useful as a tool for studying the fate of halogens in soils.     

离子色谱测定农用硫酸铵中4种杂质阴离子

建立了离子色谱法同时测定农用硫酸铵中氟、氯、溴、硫氰酸盐的分析方法。样品经水提取,Ba离子柱净化后,离子色谱法测定。4种阴离子浓度在各自线性范围内与相应峰面积呈线性关系,相关系数r＞0.999,加标回收率为80.23%～111.50%,精密度（RSD）为0.62%~9.08%。称样量为0.1g时,氟、氯的方法检出限为10mg/kg;溴、硫氰酸盐方法检出限为20mg/kg。该方法样品前处理简单、快捷,重复性及回收率均能达到检测分析要求,可以应用于农用硫酸铵中杂质阴离子的检测。     

固相萃取-离子色谱法测定甘蔗糖蜜及糖蜜酒精废液中的非氮有机酸和无机阴离子

建立了固相萃取-离子色谱测定甘蔗糖蜜及糖蜜酒精废液中乙酸、乳酸、琥珀酸、苹果酸、酒石酸、草酸、富马酸、柠檬酸、乌头酸等非氮有机酸和盐酸根、硫酸根、磷酸根等3种无机阴离子的方法。样品稀释液经强阴离子(SAX)固相萃取小柱净化除去糖类和色素等干扰基质,再用稀KOH溶液洗脱,经0.45 μm水膜过滤后,用IonPac AS15阴离子分离柱、KOH溶液梯度淋洗-抑制电导检测分离分析。考察了固相萃取小柱对待测离子的保留和洗脱条件。实验结果表明,除乙酸和乳酸的分离不完全、苹果酸与琥珀酸的组分重叠外,其余组分可达到完全分离,被测组分的浓度与其峰高在一定的范围呈良好的线性关系,检出限均低于0.20 mg/L,相对标准偏差(RSD)小于6.7%。测定了2种甘蔗糖蜜和1种糖蜜酒精废液中有机酸及无机阴离子,结果满足检测的要求,样品中各组分的加标回收率为94%～109%。     

气相色谱法检测大孔吸附树脂中的有机残留物

建立了同时检测大孔吸附树脂中苯、甲苯、二甲苯、苯乙烯、二乙苯、二乙烯苯、萘、癸烷、十一烷和十二烷等10种有机残留物的测定方法。以二氯甲烷为提取溶剂,采用超声提取法对样品进行前处理。采用气相色谱法检测,色谱柱为DB-624毛细管柱,检测器为氢火焰离子化检测器。上述10种有机残留物在12 min内能很好地分离,样品的加标回收率(n=3)为73.8%～107.9%,相对标准偏差为1.3%～4.4%,最低检测限为0.007～0.03 mg/L。本方法具有灵敏、准确、快速等特点。对9种商品树脂及其预处理品的有机残留物进行了测定,结果表明树脂预处理前后有机残留物的含量相差很大,经过预处理的树脂可以安全地应用于中药的生产。     

Organic–inorganic hybrid fluorous monolithic capillary column for selective solid‐phase microextraction of perfluorinated persistent organic pollutants

A novel construction strategy of monolithic capillary column for selectively enriching perfluorinated persistent organic pollutants was proposed. The organic–inorganic hybrid fluorous monolithic capillary column was synthesized by a “one‐pot” approach via the polycondensation of γ‐methacryloxypropyltrimethoxy‐silane, then in situ copolymerization of 1H,1H,7H‐dodecafluoroheptyl methacrylate and vinyl group on the precondensed siloxanes. The obtained monolithic columns were systematically characterized. The results demonstrated that the optimal column possessed good mechanical stability and high permeability. The adsorption capacities of the optimized monolithic column for perfluorooctanoic acid and perfluorooctane sulfonate were 0.257 and 0.513 μg/mg, respectively. Adsorption capacities of the monoliths were proved to increasing with increasing the amounts of fluorinated monomers in the fluorous monoliths. Sodium 1‐octanesulfonate, as a comparison compound, was hardly adsorbed on the fluorous monolith. In addition, the trace amounts of perfluorooctanoic acid and perfluorooctane sulfonate in water samples can be successfully concentrated about 160 times to their original concentrations by this monolithic column. These results demonstrated that the capacity and selectivity of the affinity fluorous column is high and can be applied to the selective enrichment for the perfluorinated persistent organic pollutants from environmental samples.     

Determination of anions in landfill leachates by ion chromatography

Ion chromatography has been used to determine inorganic and organic anions within landfill leachates. Two procedures are operated on split samples which have multiple dilutions and vary in sample treatment: gradient ion-exchange chromatography for inorganic anions and isocratic ion-exclusion chromatography for organic anions. Interference between carbonate and organic acid anions using ion-exclusion chromatography is avoided by treatment with octanesulphonic acid eluent. Using ion-exchange chromatography, the presence of valerate, hexanoate and heptanoate is checked (but not quantified) for a subsample which has been treated to remove chloride; these species are then determined by ion-exclusion chromatography. Analysis of certified standards (10 mg/1 certified VFA standard; Supelco, Bellefonte, PA, USA; 20–150 mg/l inorganic anions, ICMIX1-100, Glen Spectra Reference Materials, Middlesex, UK) gives good agreement (within 5% for organic anions except formate, and within 1% for inorganic anions), with R.S.D. values for all anionic species varying from 0.44–2.23.     

Challenges encountered in extending the sensitivity of US Environmental Protection Agency Method 314.0 for perchlorate in drinking water

Concerns about the potential adverse health effects of perchlorate at concentrations below the minimum reporting level (MRL) of US Environmental Protection Agency (EPA) Method 314.0 (generally recognized as 4.0 microg/l) have led to an interest in increasing the sensitivity of the method. This work describes the use of 2 mm columns with a large-loop direct injection method, a column concentration technique and this concentration technique with a background reduction step, to increase the sensitivity for the analysis of trace levels of perchlorate in high ionic strength matrices. The concentrator columns studied were the Dionex TAC LP-1 and a new Dionex high capacity Cryptand concentrator column. The use of a surrogate to monitor trapping efficiency for the concentration technique and the use of confirmational columns to minimize the potential for false positives are also discussed. The large-loop direct injection method and the column concentration methods provided acceptable data when the samples were pre-treated with solid phase pretreatment cartridges. The background reduction technique did not provide acceptable data with either of the concentrator columns evaluated.