Determination of arsenic species by inductively coupled plasma mass spectrometry with ion chromatography

Five arsenic species, trimethylarsine oxide, dimethylarsenic acid, monomethylarsonic acid, arsenobetaine and sodium arsenite, in urine were analysed by inductively coupled plasma mass spectrometry with ion chromatography (IC ICP MS). Since the toxicities of different arsenic compounds are different, speciation of arsenic compounds is very important in the investigation of metabolisms. In this paper, we applied ion chromatography (IC) as a separation device and inductively coupled plasma mass spectrometry (ICP MS) as a detection device. For separation of the five arsenic compounds, an anion-exchange column and, as mobile phase, tartaric acid were used. The eluent from the IC column was introduced directly into the nebulizer of the ICP MS and analysed at 75 amu. Detection limits were from 4 to 9 pg as arsenic.     

Speciation of metal-EDTA complexes by flow injection analysis with electrospray ionization mass spectrometry and ion chromatography with inductively coupled plasma mass spectrometry

Flow injection analysis (FIA) with ESI-MS and ion chromatography (IC) with inductively coupled plasma-MS (ICP-MS) as the complementary technique have been explored for the determination of metal ions as their metal-EDTA complexes. ESI-MS enabled the identification of metal-EDTA complexes such as [Mn(EDTA)](2-), [Co(EDTA)](2-), [Ni(EDTA)](2-), [Cu(EDTA)](2-), [Zn(EDTA)](2-), [Pb(EDTA)](2-), and [Fe(EDTA)](1-) and their MS spectral showed that these metal-EDTA complexes were present in solution. Based on the ESI-MS, ion chromatographic separation and ICP-MS detection of these complexes are possible because IC-ICP-MS requires stable metal-EDTA complex during the chromatographic separation. The separation of these metal-EDTA complexes was achieved on an anion-exchange column with a mobile phase containing 30 mM NH(4)(HPO(4))(2) at pH 7.5 within 7 min with ICP-MS providing element specific detection. The ICP-MS LODs for the metal-EDTA were in the range of 0.1-0.5 microg/L with the exception of Fe (15 microg/L). The proposed method was a simple procedure for sample processing, using direct injection of sample without removal of sample matrix and was successfully applied to the determination of metal-EDTA complexes in real samples.     

Determination of synthetic chelating agents in surface and waste water by ion chromatography-mass spectrometry

Coupling of ion chromatography with electrospray mass spectrometry (IC-MS) is a simple, sensitive and quick method for the determination of polar organic traces in water samples without derivatization. Analysis of the chelating agents ethylenediamino tetraacetate (EDTA) and diethylenetriamino pentaacetate (DTPA) in aqueous samples was done by IC-MS on an anion exchange column after simple sample preparation steps. Quantification down to a concentration level of 1 microg L(-1) even in wastewater influents and effluents was achieved utilizing 13C marked internal standards and measuring the individual [M - H+]- and stable [M - 4H+ + Fe3+]- cluster ions. The method was validated against certified, but more time consuming routine methods. Applying this method a series of several European water samples were analyzed for EDTA and DTPA indicating their nature as polar persistent pollutants.     

萃取色层分离同位素稀释ICP-MS测定空气中费克 量钚

ICP-MS测定环境样品中超痕量^2^3^9Pu时,^2^3^8UH^+会对m/z239的测量带来干扰。测得UH^+的产生几率为4.6×10^-^5,通过三正辛胺色层分离后,对铀的去除率为10^4,可以有效地去除^2^3^8UH^+离子峰对^2^3^9Pu测定的干扰。钚的回收率为75%。同位素稀释法对^2^3^9Pu的检出限为4.5×10^-^1^5g/mL,方法的定量测定限为16×10^-^1^5g/mL。用所建立的方法测得我国某地区空气中^2^3^9Pu的浓度为4.8×10^-^1^7g/m^3。     

Speciation analysis of arsenic compounds in edible oil by ion chromatography-inductively coupled plasma mass spectrometry

An inductively coupled plasma mass spectrometer (ICP-MS) was used as an ion chromatographic (IC) detector for the speciation analysis of arsenic in edible oil. The arsenic species studied include arsenite, arsenate, monomethylarsonic acid, dimethylarsinic acid, arsenobetaine and arsenocholine. Gradient elution using (NH(4))(2)CO(3) and methanol at pH 8.5 allowed the chromatographic separation of all species in less than 8 min. Effluents from the IC column were delivered to the nebulizer of ICP-MS for the determination of arsenic. The concentrations of arsenic species have been determined in several used and fresh vegetable oil samples. In this study, a microwave-assisted extraction method was used for the extraction of arsenic species from oil samples. The extraction efficiency was better than 92% and the recoveries from spiked samples were in the range of 90-105%. The precision between sample replicates was better than 8% for all determinations. The limits of detection were in the range of 0.008-0.024 ng mL(-1) for various arsenic species based on peak height, which corresponded to 0.08-0.24 ng g(-1) in the original oil sample. The major arsenic species in the used oil samples varied based on the food items cooked.     

Determination of total and soluble chromium(VI) in compost by ion chromatography–inductively coupled plasma mass spectrometry

Abstract

As part of a project investigating the air-water exchange of nutrients and inorganic micropollutants to the North Sea, the atmospheric deposition of nutrients and trace metals in their different compositions and via various pathways was investigated. Intensive sampling campaigns were organised on the research vessel Belgica (ns 21/98 campaign from September 28 to October 1, 1998 and ns 10/99 campaign from April 19 to 23, 1999), at a sampling station near the Belgian coast (Knokke-Heist) and at the University campus of Antwerp. Simulation work and remobilisation experiments were carried out to obtain a general view of the kinetics of solubilisation of the constituents under investigation. Sample treatment requires a leaching system with a quantitative recovery of the species of interest in the leaching solution within a reasonably short period of time (30 min).

For this reason, a re-circulation leaching system was developed, tested, optimised and compared with a more accepted ultrasound leaching method.     

Residue determination of glyphosate, glufosinate and aminomethylphosphonic acid in water and soil samples by liquid chromatography coupled to electrospray tandem mass spectrometry

This paper describes a method for the sensitive and selective determination of glyphosate, glufosinate and aminomethylphosphonic acid (AMPA) residues in water and soil samples. The method involves a derivatization step with 9-fluorenylmethylchloroformate (FMOC) in borate buffer and detection based on liquid chromatography coupled to electrospray tandem mass spectrometry (LC-ESI-MS/MS). In the case of water samples a volume of 10 mL was derivatized and then 4.3 mL of the derivatized mixture was directly injected in an on-line solid phase extraction (SPE)-LC-MS/MS system using an OASIS HLB cartridge column and a Discovery chromatographic column. Soil samples were firstly extracted with potassium hydroxide. After that, the aqueous extract was 10-fold diluted with water and 2 mL were derivatized. Then, 50 microL of the derivatized 10-fold diluted extract were injected into the LC-MS/MS system without pre-concentration into the SPE cartridge. The method has been validated in both ground and surface water by recovery studies with samples spiked at 50 and 500 ng/L, and also in soil samples, spiked at 0.05 and 0.5 mg/kg. In water samples, the mean recovery values ranged from 89 to 106% for glyphosate (RSD <9%), from 97 to 116% for AMPA (RSD < 10%), and from 72 to 88% in the case of glufosinate (RSD < 12%). Regarding soil samples, the mean recovery values ranged from 90 to 92% for glyphosate (RSD <7%), from 88 to 89% for AMPA (RSD <5%) and from 83 to 86% for glufosinate (RSD <6%). Limits of quantification for all the three compounds were 50 ng/L and 0.05 mg/kg in water and soil, respectively, with limits of detection as low as 5 ng/L, in water, and 5 microg/kg, in soil. The use of labelled glyphosate as internal standard allowed improving the recovery and precision for glyphosate and AMPA, while it was not efficient for glufosinate, that was quantified by external standards calibration. The method developed has been applied to the determination of these compounds in real water and soil samples from different areas. All the detections were confirmed by acquiring two transitions for each compound.     

Determination of selenium compounds in urine by high-performance liquid chromatography--inductively coupled plasma mass spectrometry

Selenium species, selenite, selenate, selenomethionine (Semet), seneloethionine (Seet) and trimethylselenonium ion (TmSe) were separated in aqueous solution using a gel-permeation (polyvinyl alcohol-based resin) GS-220 column by eluting with 25 mM tetramethylammonium hydroxide and 25 mM malonic acid at pH 7.9. The GS-220 column coupled with inductively coupled plasma mass spectrometry was used for the separation, identification, and quantification of selenium compounds present in certified reference material (CRM) No. 18 human urine from the National Institute for Environmental Studies in Japan (NIES). Spiking of the authentic standard to the urine and use of a silica-based LC-SCX cation-exchange column validated the peak of selenium compounds. High concentrations of chloride and bromide in the urine eluted from the GS-220 column formed molecular ions 40Ar37Cl+ and 81Br1H+ in the plasma, and these molecular ions created additional peaks in the chromatograms when 77Se and 82Se isotopes were monitored respectively. Thus, both the isotopes were selected concurrently for signal monitoring to eliminate the interfering signals. On the LC-SCX column, chloride and bromide were eluted with selenate and complicated its determination, but the peak of TmSe was baseline separated from rest of the Se compounds. Two unknown Se compounds were detected in both the columns. An additional Se compound having the same retention time as that of Semet was detected on the LC-SCX column. Peaks of selenite, selenate, TmSe and unknown selenium compounds in the urine were baseline separated on the GS-220 column, and were free from interferences. Therefore, the GS-220 column was used for the determination of selenium compounds in NIES CRM No. 18. Unknown Se compounds were the predominant selenium species followed by selenite, TmSe and selenate. The estimated value of TmSe as Se, by the standard additions method using the GS-220 column, was 3.42 +/- 0.17 microg l(-1) and was in good agreement with the LC-SCX value [3.38 +/- 0.21 (n=5) microg l(-1)].     

Arsenic speciation by gradient anion exchange narrow bore ion chromatography and high resolution inductively coupled plasma mass spectrometry detection

Based on gradient anion exchange chromatography (AEC), a new strategy in As-speciation was evaluated. A narrow bore chromatographic system with lower flow rates (≤300 μL) well suitable for the low flow requirements of higher efficiency nebulizers was splitless coupled to a high resolution sector field ICP MS. The AEC system takes full advantage of the detector sensitivity allowing more diluted samples (50–100 times) to be injected, delivering substantially less sample matrix to the column and a lower eluent load to the plasma. The unique plasma compatibility of the NH₄NO₃-eluent salt used in this study enabled high linear salt ramps in gradient applications, highly reproducible retention times (±1%) and detection limits in the low ng/L range. The separation conditions were applied on two different polymeric anion-exchangers: a low capacity, weakly hydrophobic material (AS11, Dionex) and a more frequently used higher capacity, higher hydrophobic material (AS7, Dionex). On both columns, As-species (As(III/V), MMA, DMA, AsB) and Cl⁻ were separated in less than nine minutes and co-elution was circumvented by adapting the separation pH to the optimal column selectivity. The key-advantage of the NH₄NO₃-eluent is that it can adopt any separation pH without compromising the eluent strength which is not possible with all other eluents used so far. The influences of chloride and methanol were investigated and found not to affect the chromatographic performance. Column deposits caused strong reversible As(v) adsorption which reduced As(v) to As(III). A corresponding phosphate excess in the injected sample eliminated the adsorption and prevented artefacts in As(v)/As(III) ratios. The method applied to ground water samples provided robust separations and is compatible with any sample preservation procedure.     

Determination of perfluorooctanesulfonate and perfluorooctanoate in water samples by SPE-HPLC/electrospray ion trap mass spectrometry

Perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) are the most notable members of an emerging class of persistent organic pollutants (POPs), perfluorochemicals (PFCs). A method for the determination of PFOS and PFOA in water samples was developed and validated in this study. Water samples collected from river and industrial effluent at Guangzhou, one of the most industrialized regions in China, were analyzed by solid-phase extraction (SPE) followed by high-performance liquid chromatography (HPLC) negative electrospray ionization (ESI) mass spectrometry. Operational parameters of the ion trap mass spectrometer were optimized to improve sensitivity and selectivity of this method. The limits of quantitation and recoveries were 2.0 ng L^− 1 and 75% for PFOA and 0.50 ng L^− 1 and 88% for PFOS, respectively. In river water samples, 2.3-33 ng L^− 1 of PFOS and < 2.0-11 ng L^− 1 of PFPA were detected. And sewage effluents contained considerably higher concentrations of PFOS and PFOA.     

Determination of glyphosate by ion chromatography

An ion chromatography system for the determination of glyphosate was described. Ion chromatograph was carried out by suppressed conductivity detection (DX-100). The eluent contained 9 mmol l⁻¹ Na₂CO₃ and 4 mmol l⁻¹ NaOH. The detection limit was 0.042 μg ml⁻¹ (S/N=3). The relative standard deviation was 1.99% and the correlation coefficient of the calibration curve for area was 0.9995. The linear range was 0.042100 μg ml⁻¹. Common inorganic ion and organic acids did not interfere. The recovery was 96.4103.2%. The method was simple, rapid, reliable and inexpensive.     

Bromate assay in water by inductively coupled plasma mass spectrometry combined with solid-phase extraction cartridges

Based on selective sorption of bromide, bromoacetic acids (BAA) and bromomethanes on solid-phase extraction (SPE) cartridges, a sensitive and convenient method was developed for the determination of bromate in waters by inductively coupled plasma mass spectrometry (ICP–MS). Dionex OnGuard Ag and reversed-phase (RP) cartridges were tested for retention characteristics for bromide, BAA and bromomethanes. When a sample acidified with nitric acid was passed through an RP cartridge, BAA and bromomethanes were retained, afterwards bromide was absorbed as a precipitate of silver bromide and bromate was unretained when the nearly neutral sample passed a combination of Ag and H cartridges. After SPE pretreatment the recovery of bromate was 96–106%, and bromide remaining in the aqueous phase was found to be less than 0.06 g L^–1 when the original bromide concentrations were less than 5 mg L^–1. Effectiveness of stacked Ag and H cartridges in removing bromide from chloride-containing samples was also examined. Common cations and other anions did not interfere with bromate determination. The detection limit for bromate is 57 ng L^–1. This method has been applied to analyse waters from various sources, and the recovery of the spiked bromate was in the range of 92–107%.     

Ion chromatography–inductively coupled plasma mass spectrometry determination of arsenic species in marine samples

Arsenic speciation analysis in marine samples was performed using ion chromatography (IC) with inductively coupled plasma mass spectrometry (ICP‐MS) detection. The separation of eight arsenic species, viz. arsenite, monomethyl arsonic acid, dimethylarsinic acid, arsenate, arsenobetaine, tetramethylarsine oxide, arsenocholine and tetramethylarsonium ion was achieved on a Dionex AS4A (weaker anion exchange column) by using a nitric acid pH gradient eluent (pH 3.3 to 1.3). The entire separation was accomplished in 12 min. The detection limits for the eight arsenic species by IC–ICP‐MS were in the range 0.03–1.6 µ g l^?1, based on 3σ of the blank response (n = 6). The repeatability and day‐to‐day reproducibility were calculated to be less than 10% (residual standard deviation) for all eight species. The method was validated by analyzing a certified reference material (DORM‐2, dogfish muscle) and then successfully applied to several marine samples, e.g. oyster, fish muscle, shrimp and marine algae. The low power microwave digestion was employed for the extraction of arsenic from seafood products. Copyright © 2004 John Wiley & Sons, Ltd.     

Speciation of chromium in waste waters by coupled column ion chromatography-inductively coupled plasma mass spectrometry

An application of coupled column ion chromatography (IC)-inductively coupled plasma mass spectrometry (ICP-MS) is presented for speciation of chromium in waste waters. By coupling an anion column with a cation column, both the cationic Cr(III) and anionic Cr(VI) species can be analyzed with detection limits below 0.5 μg/1. The separation of the interfering ions (chloride, chlorate, perchlorate, sulphate, sulphite, sulphide, thiosulphate, carbonate, cyanide and some organic compounds) from the chromium peaks is discussed, and the use of different chromium isotopes for data acquisition is compared. Based on the results, m/z 52 was considered as an ideal isotope for speciation of chromium in waste waters by the coupled column IC-ICP-MS, because it did not suffer from polyatomic interferences and due to the high sensitivity for chromium. The analysis of the waste water samples should be performed as soon as possible after sampling according to the stability tests of the species.     

离子色谱(IC)-电感耦合等离子体质谱(ICP-MS)法测定食品接触涂层制品中可迁移六价铬

此研究旨在建立食品接触涂层制品中低含量可迁移六价铬的一种快速、准确的测定方法。试样经过水和4%乙酸迁移试验后,以75 mmol/L硝酸铵溶液（调节pH=7.0）为洗脱液,经过NP5阴离子柱分离,选择碰撞（KED）监测模式,用离子色谱（IC）-电感耦合等离子体质谱（ICP-MS）法测定样品中六价铬的迁移量。实验发现,以水和4%乙酸作模拟物进行迁移试验,六价铬迁移量在0～5.0 μg/L 范围内线性关系良好,相关系数均大于0.999,检出限低至0.05 μg/kg。三种浓度水平的加标回收率试验结果为81.5%～94.7%,精密度结果为3.1%～7.2%。与紫外可见分光光度（UV-Vis）法相比,检出限更低,抗基质干扰性更好。对购于商超和电商平台的多种食品接触涂层制品进行测试,结果显示,该方法快速、准确,适用于食品接触涂层制品中低迁移量的六价铬的快速测定。     

Optimization and performance evaluation of the analysis of glyphosate and AMPA in water by HPLC with fluorescence detection

Summary The object of this work was to optimize and validate an analytical method for the analysis of glyphosate and its main metabolite AMPA (aminomethylphosphonic acid) in natural and drinking water, for sanitary control. The method uses a derivatization step which transforms glyphosate and AMPA into fluorescent products by reaction with 9-fluorenylmethylchloroformate (FMOC-Cl). The kinetics and yield of this reaction were studied by use of different samples. The derivatization products were injected directly into the liquid chromatograph and separated on an amino-functionalized silica gel column. The performance of the method (detection limit, quantification limit, linearity, and relative standard deviation) was studied and the results obtained showed the method was suitable for routine analysis of glyphosate and AMPA. An interlaboratory test with five laboratories confirmed that good results were obtained by use of this method.     

Determination of glyphosate using off-line ion exchange preconcentration and capillary electrophoresis-laser induced fluorescence detection

An enrichment method for the herbicide glyphosate is presented based on ion exchange solid phase extraction (SPE) technique. A 200-μl micro-pipette tip packed with 50 mg of Bio-Rad AG1-X8 anion exchanger beads was used for offline extraction of glyphosate from 50 ml of spiked river water sample. The retained glyphosate was eluted with 10 mM HCl and then converted quantitatively to the corresponding amine (glycine) using hypochlorite. Subsequent fluorescent labeling using naphthalene-2,3-dicarboxaldehyde (NDA)-cyanide allowed micellar electrokinetic chromatography (MEKC) separation and laser-induced fluorescence detection (LIF) with a violet diode laser. Optimization of the sample clean-up, extraction, elution, conversion and labeling steps enabled analysis of glyphosate in river water in the nanomolar range. Detection limits were 0.04 nM glyphosate in standards and 1.6 nM in spiked river.     

Development of cadmium/silver/palladium separation by ion chromatography with quadrupole inductively coupled plasma mass spectrometry detection for off-line cadmium isotopic measurements

A separation method was investigated to perform off-line cadmium isotopic measurements on a ¹⁰⁹Ag transmutation target. Ion chromatography (IC) with Q ICPMS detection (quadrupole inductively coupled plasma mass spectrometry detection) was chosen to separate cadmium from the isobarically interfering elements, silver and palladium, present in the sample. The optimization of chromatographic conditions was particularly studied. Several anion and cation columns (Dionex AG11^®, CS10^® and CS12^®) were compared with different mobile phases (HNO₃, HCl). The separation procedure was achieved with a carboxylate-functionalized cation exchange CS12 column using 0.5 M HNO₃ as eluent. The developed technique yielded satisfactory results in terms of separation factors (greater than 5) and provides an efficient solution to obtain rapidly purified cadmium fractions (decontamination factors higher 100,000 for silver and palladium) which can directly be analyzed by multi collection inductively coupled plasma mass spectrometry (MC ICPMS). By applying the proposed procedure, accurate and precise cadmium isotope ratios were determined for the irradiated ¹⁰⁹Ag transmutation target.     

Determination of priority organic micro-pollutants in water by gas chromatography coupled to triple quadrupole mass spectrometry

A multiclass method has been developed for screening, quantification and confirmation of organic micro-pollutants in water by gas chromatography coupled to mass spectrometry with a triple quadrupole analyzer. The work has been focused on the determination of more than 50 compounds belonging to different chemical families: 19 organochlorine and organophosphorus insecticides, 6 herbicides, 7 polychlorinated biphenyls, 16 polycyclic aromatics hydrocarbons, 2 brominated diphenyl ethers, and 3 octyl/nonyl phenols and pentachlorobenzene. Most of these analytes are included in the list of priority substances in the framework on European Water Policy.Analyte extraction was performed by solid phase extraction using C₁₈ cartridges, and five isotopically labeled standards were added before extraction as surrogates. Analyses were performed by gas chromatography with tandem mass spectrometry (MS/MS) in electron impact mode. Accuracy and precision were evaluated by means of recovery experiments using water samples fortified at two concentration levels (25 and 250 ng L⁻¹), with satisfactory results for most of analytes. The excellent selectivity and sensitivity reached in selected reaction monitoring mode allowed us satisfactory quantification and confirmation at levels as low as 25 ng L⁻¹. Two MS/MS transitions were acquired for each analyte, using the Q/q intensity ratio as a confirmatory parameter. The method developed was applied to the analysis of surface, ground and wastewater samples collected from the Valencia Region (Spain).Analytical methodology using negative chemical ionization mode was also validated for the organochlorine compounds selected, showing a superior sensitivity and lower detection limits.     

Determination of iminodiacetic acid in the glyphosate by ion chromatography

In this paper,a simple method based on ion chromatography（IC） with conductivity detection was developed for the determination of iminodiacetic acid（IDA） in the herbicide of glyphosate.Under optimized chromatographic conditions,good linear relationship,sensitivity and reproducibility were obtained.The detection limit（LOD） for IDA obtained by injecting 25 μL of sample was 31.8 μg/L（S/N = 3）.Relative standard deviation（RSD） of repeated analysis for the peak areas was less than 1.53%（n = 6）.A spiking study was performed with satisfactory recoveries between 92.8%and 103.6%.It was confirmed that this method could be applied in glyphosate products.