Arsenic Compounds In Urine Research Articles

Biomarkers of seafood intake during pregnancy – Pollutants versus fatty acids and micronutrients

Intake of fish and seafood during pregnancy may have certain beneficial effects on fetal development, but measurement of intake using questionnaires is unreliable. Here, we assessed several candidate biomarkers of seafood intake, including long-chain omega 3 fatty acids (n-3 LCPUFA), selenium, iodine, methylmercury, and different arsenic compounds, in 549 pregnant women (gestational week 29) in the prospective birth cohort NICE (Nutritional impact on Immunological maturation during Childhood in relation to the Environment). Proportions of the fatty acids eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA) in erythrocytes were measured using gas chromatography with flame ionization detector. Selenium was measured in blood plasma and erythrocytes, mercury and arsenic in erythrocytes, and iodine and several arsenic compounds in urine, using inductively coupled plasma mass spectrometry, arsenic compounds after first being separated by ion exchange high-performance liquid chromatography (HPLC). Each biomarker was related to intake of total seafood and to intake of fatty and lean fish, and shellfish in third trimester, estimated from a semi-quantitative food frequency questionnaire filled out in gestational week 34. The pregnant women reported a median total seafood intake of 184 g/week (5th-95th percentiles: 34–465 g/week). This intake correlated most strongly with erythrocyte mercury concentrations (rho = 0.49, p < 0.001), consisting essentially of methylmercury, followed by total arsenic in erythrocytes (rho = 0.34, p < 0.001), and arsenobetaine in urine (rho = 0.33, p < 0.001), the main form of urinary arsenic. These biomarkers correlated well with intake of both fatty fish, lean fish, and shellfish. Erythrocyte DHA and plasma selenium correlated, although weakly, mainly with fatty fish (rho = 0.25 and 0.22, respectively, both p < 0.001). In conclusion, elevated concentrations of erythrocyte mercury and urinary arsenobetaine can be useful indicators of seafood intake, more so than the n-3 LCPUFAs. However, the relative importance of the biomarkers may differ depending on the type and amount of seafood consumed.

Speciation Analysis of Arsenic Compounds by HPLC-ICP-MS: Application for Human Serum and Urine.

A high-performance liquid chromatography (HPLC) in combination with inductively coupled plasma mass spectrometry (ICP-MS) as an elemental specific detector was used for the speciation analysis of arsenic compounds in urine and serum samples from Vietnam. Five arsenic species including arsenite (AsIII), arsenate (AsV), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), and arsenobetaine (AsB) were studied. A gradient elution of ammonium carbonate ((NH4)2CO3), ethylenediaminetetraacetic acid disodium salt (Na2EDTA), and methanol at pH 9.0 utilizing Hamilton PRP-X100 strong anion-exchange column allowed the chromatographic separation of five arsenic species. In this study, urine and serum samples were prepared by dilution in solvent and protein precipitation by trichloroacetic acid, respectively. The extraction efficiency was greater than 91% for urine matrix, and recoveries from spiked samples were in the range of 94–139% for the arsenic species in human serum. The method limit of detection (MDL) and limit of quantification (MQL), which were calculated by signal to noise ratio, were found to be 0.3–1.5 and 1.0–5.0 ng·mL−1, respectively. The concentration of arsenic species in 17 pairs of urine and serum samples from Vietnam was also quantified and evaluated. The major species of arsenic in the urine and serum samples were AsB and DMA.

Tracing for arsenic exposure--a differentiation of arsenic compounds is essential for the health assessment

Arsenic is ubiquitous and harmful to health in occupation and environment. Arsenic exposure is measured through analysis of arsenic compounds in urine. The identification of several arsenic species is necessary to understand the hazardous potential of the arsenic compounds which differ highly in their toxicity. To estimate the extent of an occupational exposure to arsenic, arsenic species were evaluated for the first time by the working group "Setting of Threshold Limit Values in Biological Material" of the DFG Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area and Biologische Arbeitsstoffreferenzwerte (BAR) of 0.5 μg / L urine for arsenic (III), 0.5 μg / L urine for arsenic (V), 2 μg / L urine for monomethylarsonic acid (MMA) and 10 μg / L urine for dimethylarsinic acid (DMA) were set. If the reference value for total arsenic is exceeded, a further differentiation of arsenic species now enables to estimate the individual health risks taking into account special influences such as seafood consumption.

Exceptions in patterns of arsenic compounds in urine of acute promyelocytic leukaemia patients treated with As2O3.

Arsenic trioxide (As(III) in solution) has been shown to be the most active single agent in combating acute promyelocytic leukemia (APL). It is metabolized and excreted via urine as monomethylarsonic acid (MMA), dimethylarsinic acid (DMA) and As(V), along with excess As(III). In our study eight APL patients were treated (intravenously) with 0.15 mg As2O3/kg/day. During the therapy As(III) and its metabolites were followed in pre- and post-infusion urine using HPLC for separation followed by on-line detection using hydride generation-atomic fluorescence spectrometry. Five patients had a normal excretion pattern of residual arsenic compounds in morning pre-infusion urine, with 15-25% of As(III), 35-55% of DMA, 25-30% of MMA and 1-5% of As(V), while three patients showed unexpected exceptions from typical excretion patterns of arsenic compounds (i) a high DMA/MMA ratio (factor 5.3), (ii) severe As(III) oxidation (10.2% As(III) converted to As(V)) or (iii) the presence of an excessive amount of As(III) (average 30.4% of total arsenic). Intriguing was the occurrence of post-infusion oxidation of As(III) to As(V) observed in almost all patients and being especially high (>40%) in patient with increased residual As(V). Results indicate that arsenic metabolites patterns can be unpredictable. Observed high levels of un-metabolised As(III) are a warning signal for side effects and for routine determination of arsenic metabolites during first days of treatment. High or low percentages of MMA or DMA did not show any observable effect on treatment results, while clear presence of post-infusion As(V) supports theoretical claims of in vivo oxidation (detoxification) of As(III) to As(V) associated with various metabolic processes.

Sequential extraction of inorganic arsenic compounds and methyl arsenate in human urine using mixed‐mode monolithic silica spin column coupled with gas chromatography‐mass spectrometry

A sequential analytical method was developed for the detection of arsenite, arsenate, and methylarsenate in human urine by gas chromatography-mass spectrometry (GC-MS). The combination of a derivatization of trivalent arsenic compounds by 2,3-dithio-1-propanol (British antilewisite; BAL) and a reduction of pentavalent arsenic compounds (arsenate and methylarsenate) were accomplished to carry out the analysis of arsenic compounds in urine. The arsenic derivatives obtained using BAL were extracted in a stepwise manner using a monolithic spin column and analyzed by GC-MS. A linear curve was observed for concentrations of arsenic compounds of 2.0 to 200 ng/mL, where the correlation coefficients of calibration curves were greater than 0.996 (for a signal-to-noise (S/N) ratio >10). The detection limits were 1 ng/mL (S/N > 3). Recoveries of the targets in urine were in the range 91.9-106.5%, and RSDs of the intra- and interday assay for urine samples containing 5, 50, and 150 ng/mL of arsenic compounds varied between 2.95 and 13.4%. The results from real samples obtained from a patient suspected of having ingested As containing medications using this proposed method were in good agreement with those obtained using high-performance liquid chromatography with inductively coupled plasma mass spectrometry.

8-Hydroxy-2′-deoxyguanosine and arsenic compounds in urine and serum of a 4-year-old child suffering from acute promyelocytic leukemia during treatment with arsenic trioxide

Arsenic trioxide (ATO) is an effective agent for acute promyelocytic leukemia (APL). In this study, the concentrations of dimethylarsinic acid (DMA), monomethylarsonic acid (MMA), As (V), As (III), and 8-hydroxy-2′-deoxyguanosine (8-OHdG) in urine and/or serum of a 4-year-old APL patient were followed during ATO treatment. In comparison with a similar analysis previously published for an 85-year-old APL patient, the levels of arsenic compounds and the percentages of MMA and DMA in the present child patient were lower than those of the old patient. Significant positive correlation of 8-OHdG was observed only with DMA, and not with other arsenic compounds. These results are quite different from those of our previous study on an old APL patient during ATO treatment. When arsenic poisoning is diagnosed, it seems important to take into account the differences in the arsenic metabolism according to the ages of subjects. This study is the first to show the relationship between the levels of 8-OHdG and arsenic compounds in urine of a child APL patient treated with ATO.

8-Hydroxy-2′-deoxyguanosine (8-OHdG) as a possible marker of arsenic poisoning: a clinical case study on the relationship between concentrations of 8-OHdG and each arsenic compound in urine of an acute promyelocytic leukemia patient being treated with arsenic trioxide

Arsenic trioxide (ATO) is an effective therapeutic agent for acute promyelocytic leukemia (APL). In the present study, the concentrations of 8-hydroxy-2′-deoxyguanosine (8-OHdG) and arsenic compounds [(dimethylarsinic acid (DMA), monomethylarsonic acid (MMA), As(V), and As(III)] in urine of an APL patient were determined during ATO treatment. The concentrations of 8-OHdG, DMA, and MMA were increased, especially during the fi rst consolidation therapy. Signifi cant positive correlations were observed between concentrations of 8-OHdG and DMA, between concentrations of 8-OHdG and MMA, and between concentrations of 8-OHdG and the sum of arsenic compounds. The present study supports the idea that urinary 8-OHdG can be a marker for arsenic poisoning, when it is detected together with DMA and MMA. In addition, this study is the fi rst to show the relationship between 8-OHdG and levels of arsenic compounds in urine of an APL patient being treated with ATO.

Determination of seven arsenic compounds in urine by HPLC-ICP-DRC-MS: a CDC population biomonitoring method

A robust analytical method has been developed and validated by use of high-performance liquid chromatography inductively coupled plasma mass spectrometry with Dynamic Reaction Cell (DRC) technology that separates seven arsenic (As) species in human urine: arsenobetaine (AB), arsenocholine, trimethylarsine oxide (TMAO), arsenate (As(V)), arsenite (As(III)), monomethylarsonate, and dimethylarsinate. A polymeric anion-exchange (Hamilton PRP X-100) column was used for separation of the species that were detected at m/z 75 by ICP-DRC-MS (PerkinElmer SCIEX ELAN DRCII) using 10% hydrogen-90% argon as the DRC gas. The internal standard (As) is added postcolumn via an external injector with a sample loop. All analyte peaks were baseline-separated except AB and TMAO. Analytical method limits of detection for the various species ranged from 0.4 to 1.7 microg L(-1) as elemental As. As(III) conversion to As(V) was avoided by adjusting the urine sample to <pH 6. Analyses of the National Institute of Standards and Technology standard reference material (SRM) 2670 and 2670a elevated and National Institute for Environmental Studies certified reference material (CRM) no. 18 for arsenic species yielded results within the certified SRM-CRM limits for As species; likewise, the sum of all species compared favorably to SRM 2670 and 2670a target values for total As. This As speciation method is now being used in a production mode for the analysis of a US population survey, the National Health and Nutrition Examination Survey, as well as for other biomonitoring studies of As exposure. This method meets our requirement for sample throughput of 2,000-3,000 sample analyses per year.

Simple and selective determination of arsenite and arsenate by electrospray ionization mass spectrometry

Arsenic pollution of public water supplies has been reported in various regions of the world. Recently, some cancer patients are treated with arsenite (As III); most Japanese people consume seafoods containing large amounts of negligibly toxic arsenic compounds. Some of these arsenic species are metabolized, but some remain intact. For the determination of toxic As III, a simple, rapid and sensitive method has been developed using electrospray ionization mass spectrometry (ESI-MS). As III was reacted with a chelating agent, pyrrolidinedithiocarbamate (PDC, C 4H 8NCSS –) and tripyrrolidinedithiocarbamate-arsine, As(PDC) 3, extracted with methyl isobutyl ketone (MIBK). A 1 μL aliquot of MIBK layer was directly injected into ESI-MS instrument without chromatographic separation, and was detected within 1 min. Arsenate (As V) was reduced to As III with thiosulfate, and then the total inorganic As was quantified as As III. This method was validated for the analysis of urine samples. The limit of detection of As was 0.22 μg L −1 using 10 μL of sample solution, and it is far below the permissible limit of As in drinking water, 10 μg L −1, recommended by the WHO. Results were obtained in < 10 min with a linear calibration range of 1–100 μg L −1. Several organic arsenic compounds in urine did not interfere with As III detection, and the inorganic As in the reference materials SRM 2670a and 1643e were quantified after the reduction of As V to As III.

Speciation of Arsenic Compounds in Urine from Occupationally Unexposed and Exposed Persons in the U.K. Using a Routine LC-ICP-MS Method

This paper describes a routine, robust, and reproducible liquid chromatography-inductively coupled plasma-mass spectrometry (LC-ICP-MS) speciation method for five arsenic compounds [arsenobetaine (AB), arsenite, arsenate, monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA)] in urine. Concentrations of these arsenic species in urine samples are reported in two sets of non-occupationally exposed controls with one set having consumed fish within 24 h (n = 31) and the other not having consumed fish for 48 h (n = 34). Arsenic species in urine samples from workers in both the timber treatment industry (n = 49) and semiconductor industry (n = 46) are also reported. The arsenic content in all of the samples was also determined using hydride-generation coupled with ICP-MS. The results show that urine samples from people not occupationally exposed to arsenic contain low levels of DMA, MMA, and AB and that only urine from smokers contained any inorganic arsenic. Consumption of seafood was seen to significantly increase the levels of AB and DMA in the unexposed persons. Urine samples from the semiconductor workers exhibited significantly higher levels of arsenite, arsenate, and DMA than the unexposed samples. The urine samples from timber treatment workers exhibited significantly higher levels of four arsenic species (not AB) than those observed in both the control groups and the semi-conductor workers.

Speciation of arsenic compounds in human urine by HPLC/hexapole collision cell ICP-MS

The analytical conditions for the simultaneous determination of arsenic(As) compounds in human urine were examined using high-performance liquid chromatography (HPLC) with an ion-exchange column combined with a hexapole collision cell inductively coupled plasma mass spectrometer. The addition of 0.1 mM EDTA to the mobile phase of HPLC (a mixture of 10 mM NH4NO3 and 0.05% HNO3, pH 3.1) was necessary for good reproducibility of the peaks. The five As species {As(V), monomethylarsonic (MMA), dimethylarsinic (DMA), As(III), and arsenobetain (AB)} were separated within 14 min, however, arsenocholine(AC), trimethylarsine oxide (TMAO) and tetramethylarsonium (TeMA) were not individually separated but eluted together at about 40 min of retention time. This method was applied to urine samples from 8 male Japanese. Although As(V), MMA, DMA, and AB were detected in all urine samples, the relative amounts of these compounds were different depending on the person. The order of concentrations of arsenic compounds in urine from 4 person were AB>DMA>MMA>As(V), but those in the other samples were AB = DMA or AB<DMA, suggesting the individual difference in the eating habits of sea foods.

High performance liquid chromatography inductively coupled plasma mass spectrometry for speciation of arsenic compounds in urine

Speciation of urinary arsenic is very important to know the extent of human exposure to inorganic arsenic and also from toxicity point of view. A high performance liquid chromatography inductively coupled plasma mass spectrometry (HPLC-ICP-MS) system for speciation of arsenite, arsenate, monomethyl arsonic acid (MMAA), dimethyl arsenic acid (DMAA) and arsenobetaine (AB) in a single run in urine samples has been developed. The method is based on anion exchange high performance liquid chromatography (HPLC) coupled on-line to inductively coupled plasma mass spectrometer (ICP-MS). Detection limits for the five arsenic species in urine samples are between 0.01 and 0.04 μg l −1. To validate the method, Standard Reference Material, toxic metals in freeze-dried urine SRM 2670 containing both normal and elevated levels of arsenic have been analyzed for arsenic species. Our results of arsenic species in Standard Reference Material SRM 2670 have been compared with the results of seven other laboratories. The method has been applied to determine the arsenic species in urine samples of two groups of people from two arsenic-affected villages of two districts, out of the nine affected districts of West Bengal, India. These two groups were using arsenic-contaminated water a few years ago, but are now supposed to be using safe water for drinking and cooking, as safe sources have been installed. From their urine speciation, the nature of exposure of individuals to arsenic compound could be predicted. It is concluded that, even though these groups are using safe water, they cannot avoid, from time to time, arsenic contamination as many water sources of the surrounding areas are arsenic contaminated.

Speciation of arsenic compounds in urine by LC-ICP MS

The method validation for the speciation of five arsenic species in urine samples by liquid chromatography hyphenated to inductively coupled plasma mass spectrometry is described. Arsenic species which are identified and quantified in urine samples are the anions of arsenic(III), arsenic(V), monomethylarsonic acid and dimethylarsinic acid, and the cationic arsenobetaine. Detection limits were obtained in the range 0.3–0.4 μg As l−1 while the repeatability was in the range 3–4% (RSD) for concentrations above five times the detection limit. Urine samples could be analysed directly after a ten-fold dilution step. Arsenic compound concentrations were determined in urine samples from a volunteer who consumed a portion of tuna fish high in arsenobetaine. It was found that arsenobetaine was excreted rapidly via the urine with maximum concentrations after 12 h. Nearly complete arsenobetaine excretion was reached after 48 h. Background levels of arsenic compounds were determined in 61 urine samples from non-exposed inhabitants of The Netherlands. © 1998 John Wiley & Sons, Ltd.

Determination of inorganic and organic arsenic compounds in urine using ion chromatography with ICP-MS.

Determination of inorganic and organic arsenic compounds in urine using ion chromatography with ICP-MS.

Determination and Speciation of Arsenic in Human Urine by Ion-Exchange Chromatography/Flow Injection Analysis with Hydride Generation/Atomic Absorption Spectroscopy

A flow injection-hydride generation/atomic absorption spectroscopic method for the measurement of total urinary arsenic and for the selective determination of inorganic arsenic, monomethylarsonic acid (MMAA), and dimethylarsinic acid (DMAA) was developed. Destruction of the organic matrix is necessary to measure total arsenic content of urine samples. Digestion of this matrix with HNO3-H2SO4-H2O2 is described. The separation of inorganic, monomethylated, and dimethylated arsenic compounds in urine was performed with ion-exchange chromatography on AG 50 W-X8 resin. Detection limits of 2 ppb for each arsenic form and of 3 ppb for total arsenic in urine analyzed after mineralization were found. Recoveries in triplicate urine samples spiked with 10 ppb inorganic arsenic, 20 ppb MMAA, and 40 ppb DMAA were 93, 91, and 85%, respectively. The precision (relative standard deviation) of the method obtained in 10 replicate analyses of urine samples spiked with arsenic metabolites varied from 3.2 to 4.6%. This method is applicable to urine samples in studies relating to arsenic exposure and its monitoring.

Speciation of eight arsenic compounds in human urine by high-performance liquid chromatography with inductively coupled plasma mass spectrometric detection using antimonate for internal chromatographic standardization

Four anionic and four cationic arsenic compounds in urine were separated by anion- and cation-exchange high-performance liquid chromatography and detected by inductively coupled plasma mass spectrometry (ICP-MS) at m/z 75. The species were the anions arsenite, arsenate, monomethylarsonate and dimethylarsinate and the cations arsenobetaine, trimethylarsine oxide, arsenocholine and the tetramethylarsonium ion. Hexahydroxyantimonate(III) was co-chromatographed with the arsenic anions but detected at m/z 121 and used as an internal standard for their qualitative analysis. Arsenite was prone to oxidation to arsenate in urine but was stable after at least 4-fold dilution of the urine with water. Arsenite was unstable in both urine samples and standard mixtures when diluted with the basic (pH 10.3) mobile phase used for anion chromatography. This could not be prevented by adding ascorbic acid as antioxidant. The argon chloride interference at m/z 75 was eliminated by chromatographic separation of the chloride present in the sample from the arsenic analytes. The ClO+ ion detected at m/z 51 and 53 was used to monitor the retention time of chloride in the anion-exchange system. The chloride eluted about 100 s after the last analyte peak and the intensity of ArCl+ was negligible even after injection of a 1% NaCl solution (less than 200 ions s–1). The recovery of all arsenic species in urine was close to 100%. The chromatographic peaks were evaluated by their peak heights and calibration was carried out by the method of standard additions. The calibration graphs were linear for all species (r > 0.999). The limits of detection were 3–6 ng cm–3 for the cations and 7–10 ng cm–3 for the anions in urine.

Estimation of the method evaluation function for the determination of hydride-generating arsenic compounds in urine by flow-injection atomic-absorption spectrometry

A direct flow-injection atomic-absorption spectrometric (FIA—AAS) method for the assessment of inorganic arsenic compounds and their metabolites was developed and statistically evaluated by the estimation of the method evaluation function (MEF), which provides detailed information on the analytical performance of the method, i.e., the average combined uncertainty and the magnitude of potential systematic errors. The method evaluation study demonstrated that the use of standard addition was a necessity to obtain an acceptable method performance at low concentrations typical for low dose exposure. In contrast the use of calibration curves resulted in a method with reduced sensitivity and high systematic error. The developed method, using standard addition, had a limit of detection (2.9 μg/l.) sufficiently low for the determination of hydride-generating arsenic species in urine from non-exposed and low exposed persons. Organoarsenicals such as arsenobetaine and arsenocholine are not detected by this method. Hence, the contribution of these compounds derived from a diet containing seafood does not affect the monitoring of inorganic arsenic compounds after occupational or environmental exposure. The high capacity of the FIA—AAS system (three minutes per sample measured by standard addition) together with the low limit of detection makes this method suitable for biological monitoring of inorganic arsenic exposure even though standard addition is required.

Concentrations of arsenic in urine of the general population in Sweden

The concentration of the sum of the metabolites of inorganic arsenic (inorganic arsenic, methylarsonic acid and dimethylarsinic acid) as well as the concentration of organic arsenic compounds, mainly in the form of arsenobetaine, in the urine of human subjects from two cities in Sweden have been studied. The median concentration of metabolites of inorganic arsenic was ∼8 μg As/g creatinine, independent of place of residence, sex, smoking and consumption of beer and wine. However, subjects who frequently ate flatfish and crustacea had somewhat higher (1.5 times) concentrations than those who very seldom ate such food. Flatfish, mainly in the form of plaice, and crustacea were found to be the main source of organic arsenic compounds. Subjects eating this type of seafood more than once a week had ∼ 40 μg organic As/g creatinine (median value), compared with about 12 μg organic As/g creatinine in subjects who very seldom ate it. Other types of seafish or freshwater fish did not give rise to elevated concentrations of arsenic in the urine. The total range of organic arsenic compounds in urine was < 1 to 525 μg As/g creatinine.