Determination Of Arsenic In Urine Research Articles

Interference-free determination of arsenic in urine by atomic absorption using two-stage probe atomization in a graphite furnace

Inductively coupled plasma mass spectrometry, hydride generation atomic absorption spectrometry and graphite furnace atomic absorption spectrometry are presently used to determine total arsenic in urine, but after labor consuming sample pretreatment. Therefore, we proposed a new approach to solve this problem using two-stage probe atomization. High-resolution continuum source graphite furnace atomic absorption spectrometer was equipped with the probe accessory for that. The sample consisting of 15 μL urine and 20 μg Pd-modifier was dried on the furnace bottom at smooth heating up to 120 оС and atomized at 2300 оС with internal Ar flow. The resulting vapors of As condensed on a tungsten probe installed above the dosing hole. At the same time, Ar flow removed an essential part of the matrix components without condensation. At the second atomization stage at 2300 оС and interrupted internal gas flow, the probe was lowered into the furnace and heated by electric current to accelerate condensate evaporation. This procedure fully separates the analytical signal from the finely structured molecular background. Matrix interference disappears due to significantly different rates of As and urinary phosphates binding with Pd at temperature of 120 °C and distillation on the probe. The limit of As detection in urine is 1.5 μg L−1 and quantification range is 50–1000 μg L−1 that almost covers the entire patients' urine concentration range of interest for environmentalists and physicians.

NAA methods for determination of nanogram amounts of arsenic in biological samples

The determination of arsenic at natural levels in biological materials remains difficult. Many analytical techniques cannot detect the low levels present in typical biological tissues and other techniques suffer from interferences. This paper reviews uses of neutron activation analysis (NAA) at NIST to determine nanogram amounts of arsenic in biological reference materials with radiochemical (RNAA) or instrumental (INAA) procedures. INAA is compromised by high activities from 24Na, 82Br, and 32P that may be formed during irradiation of biological tissues, and result in detection limits as high as 0.1 mg. Lower detection limits have been achieved using state-of-the-art gamma-ray spectrometry systems in INAA and a variety of procedures in RNAA. These techniques and procedures were applied recently at NIST to the determination of arsenic in urine, nutritional supplements, and total diet samples.

Determination of arsenic in urine by hydride generation-atomic fluorescence spectroscopy

目的 建立尿中砷的氢化物原子荧光测定方法.方法按照 的要求进行实验室实验及现场实验,研究了酸度、硼氢化钾浓度、载气及屏蔽气流速等因素对测定的影响.结果尿砷含量在0.0～160.0μg/L范围内呈线性关系,线性相关系数大于0.999 0,本法检出限为0.321μg/L(取尿样5ml).对尿砷含量为10.0、40.0、80.0、160.0 μg/L的配制样,测得方法相对标准偏差(RSD)为0.87%～1.75%,标准加入回收率为95%～105%,样品在4℃下可保存2周.结论该方法各项指标均达到 的要求,适用于职业接触的劳动者尿中砷的检测。

Population-based biomonitoring in the Czech Republic: urinary arsenic.

The method of Guo et aL (AnaL Chim. Acta, 1997, 349, 313-318) for the determination of the toxicologically relevant arsenic in urine was verified and then used for the determination of arsenic in urine of the Czech population for monitoring purposes. Statistical evaluation at the level alpha = 0.05 did not prove any significant differences between industrial and agricultural regions, between males and females and smokers and nonsmokers. Likewise no differences were found among children in all the regions monitored. In the adult population small differences were found between some regions but these differences were not dependent on industrial pollution. The values of toxicologically relevant arsenic are low for all regions. The summarised value of the median for all groups together is 3.5 microg (g creatinine)(-1).

Determination of arsenic in urine by atomic absorption spectrophotometry for biological monitoring of occupational exposure to arsenic

An atomic absorption spectrophotometric (AAS) method was successfully applied to analysis of urine for arsenic (As) as a measure of biological monitoring of occupational exposure to As in Vietnam. The application of the method to urine samples from 75 non-exposed control urbanites (after 2-day abstinence from sea foods) gave a reference level of 62.4±11.6 μg/l (as mean±S.D.), from which the upper limit of the normal value (74 μg/l as mean±1S.D.) and the acceptable limit (100 μg/l as mean±3S.D.) were deduced. Further application to urine samples from 147 workers occupationally exposed to As in Bacthai Non-ferrous Metallurgic Corporation showed significantly elevated levels of As in urine, with mean±S.D. of 78.5±20.2 μg/l. Improvement of working conditions to reduce As exposure resulted in substantial reduction in the ratio of those with urinary As at the level in excess of the acceptable limit. The practical importance of total arsenic determination in urine after 2-day sea food abstinence is discussed in connection with current conditions in analytical laboratories in Vietnam.

Speciation determination of arsenic in urine by high-performance liquid chromatography-hydride generation atomic absorption spectrometry with on-line ultraviolet photooxidation.

A coupled system for arsenic speciation determination based on high-performance liquid chromatography (HPLC), on-line UV photooxidation and continuous-flow hydride generation atomic absorption spectrometry (HGAAS) was built from commercially available modules with minor modifications to the electronic interface, the software and the gas-liquid separator. The best results were obtained with strong anion-exchange columns, Hamilton PRP X-100 and Supelcosil SAX 1, and gradient elution with phosphate buffers containing KH2PO4-K2HPO4. The on-line UV photooxidation with alkaline peroxodisulfate, 4% m/v K2S2O8-1 mol l-1 NaOH, in a PTFE knotted reactor for 93 s ensures the transformation of inorganic AsIII, monomethylarsonate, dimethylarsinate, arsenobetaine, arsenocholine, trimethylarsine oxide and tetramethylarsonium ion to arsenate. About 32-36 HPLC-UV-HGAAS runs could be performed within 8 h, with limits of detection between 2 and 6 micrograms l-1 As, depending on the species. The method was applied to the analysis of spot urine samples and certified urine reference materials (CRMs). Upon storage at 4 degrees C, reconstituted CRMs are stable for at least 2 weeks with respect to both their total arsenic content and the individual species distribution.

Minimization of phosphate interference in the direct determination of arsenic in urine by electrothermal atomic absorption spectrometry

A direct method for the determination of arsenic in urine by Zeeman atomic absorption spectrometry has been proposed by graphite furnace atomization with (NH 4) 3RhCl 6 + citric acid as a mixed matrix modifier. Different matrix modifiers including palladium, nickel and rhodium, were used for the elimination of phosphate interference, which was most troublesome in the arsenic determination in urine. Rhodium was preferred to palladium and nickel; in its presence the determination of arsenic in urine can tolerate a char temperature of 1600 °C, a temperature high enough to drive off the urine matrix including calcium phosphate without losing arsenic. The citric acid in the furnace evolved active gases and carbon upon decomposition thus facilitating the creation of a favorable reducing environment for the formation of a Rh-As alloy or intermetallic compounds which stabilized arsenic to a high temperature. In the determination of 1 ng of arsenic, 1.0 mg ml −1 phosphate in the form of calcium phosphate can be tolerated. Analytical results obtained for standard urine sample compared (>92% recovery) well with the certified value. The lowest concentration of arsenic that could be determined was 20 ng ml −1 in the undiluted urine.

Determination of urinary arsenic by solvent extraction and electrothermal atomic absorption spectrometry. A comparison with directly coupled high-performance liquid chromatography–inductively coupled plasma mass spectrometry

A modified method for the determination of arsenic in urine using solvent extraction with toluene and ETAAS is described. The urine samples were acidified with HCl and reduced with KI followed by a stripping step from the organic solvent with a 1% HNO3 solution. Only inorganic, mono- and dimethylated arsenic species, correlated with occupational exposure, were determined while trimethylated species, such as arsenobetaine, arising from seafood consumption, were not extracted. The results were compared with those obtained by HPLC–ICP-MS. A good agreement between the two different determinations was found and the solvent extraction method was considered suitable for a correct evaluation of occupational exposure to inorganic arsenic.

Nondestructive determination of arsenic in urine by epithermal neutron activation analysis and Compton suppression

Epithermal neutron activation analysis, in conjunction with Compton suppression, has been employed to determine arsenic levels in artificially doped urine samples. Typical detection limits were of the order of 10 ng/g. Replicate determinations gave precision values between 2 and 12%, whereas accuracy measurements were between +/- 1 and +/- 20%. Biological and geological reference materials from the National Institute of Standards and Technology (NIST) were also analyzed for arsenic content. Typically, the precision achieved again was between 2 and 12%, whereas the accuracy measurements were in excellent agreement with the certified values.

Assessment of occupational exposure to inorganic arsenic based on urinary concentrations and speciation of arsenic.

An analytical speciation method, capable of separating inorganic arsenic (As (V), As (III] and its methylated metabolites (MMAA, DMAA) from common, inert, dietary organoarsenicals, was applied to the determination of arsenic in urine from a variety of workers occupationally exposed to inorganic arsenic compounds. Mean urinary arsenic (As (V) + As (III) + MMAA + DMAA) concentrations ranged from 4.4 micrograms/g creatinine for controls to less than 10 micrograms/g for those in the electronics industry, 47.9 micrograms/g for timber treatment workers applying arsenical wood preservatives, 79.4 micrograms/g for a group of glassworkers using arsenic trioxide, and 245 micrograms/g for chemical workers engaged in manufacturing and handling inorganic arsenicals. The maximum recorded concentration was 956 micrograms/g. For the most exposed groups, the ranges in the average urinary arsenic speciation pattern were 1-6% As (V), 11-14% As (III), 14-18% MMAA, and 63-70% DMAA. The highly raised urinary arsenic concentrations for the chemical workers, in particular, and some glassworkers are shown to correspond to possible atmospheric concentrations in the workplace and intakes in excess of, or close to, recommended and statutory limits and those associated with inorganic arsenic related diseases.

Determination of arsenic in urine by graphite platform furnace atomization atomic absorption spectrometry

Determination of arsenic in urine by graphite platform furnace atomization atomic absorption spectrometry

Zeeman effect electrothermal atomic absorption spectrophotometry with matrix modification for the determination of arsenic in urine.

Arsenic was determined in urine by electrothermal atomic absorption spectrophotometry using Zeeman Effect background correction and after matrix modification with 5% nickel nitrate. Mean recovery of urine samples spiked with 100 micrograms . L-1 dimethylarsinic acid was 97.9 micrograms . L-1. Within-run CV was 2.4%, between-run CV was 7.3% and the detection limit was determined to be 10.0 micrograms . L-1. The method can be used for the rapid screening of urine samples for elevated arsenic levels.

Direct determination of arsenic in urine by differential pulse anodic stripping voltammetry

Various parameters affecting the behaviour of arsenic in differential pulse anodic stripping voltammetry (Dpasv) have been studied, such as the electrodeposition potential, working electrode, electrolysis time and the nature of the electrolyte solution. It was found that under suitable conditions arsenic(III) can be determined directly in diluted urine byDpasv. For the quantitative determination of arsenic(III) in urine calibration curves were recorded and recovery experiments have been carried out. A detection limit of 20Μg As/l has been found and in the concentration range of 0.3–1.0 mg/l the coefficient of variation was better than 5%.

Determination of arsenic in urine by atomic absorption spectrometry with electrothermal atomization

Determination of arsenic in urine by atomic absorption spectrometry with electrothermal atomization