scholarly journals Sample Preparation and Storage Can Change Arsenic Speciation in Human Urine

1999 ◽  
Vol 45 (11) ◽  
pp. 1988-1997 ◽  
Author(s):  
Jörg Feldmann ◽  
Vivian W-M Lai ◽  
William R Cullen ◽  
Mingsheng Ma ◽  
Xiufen Lu ◽  
...  

Abstract Background: Stability of chemical speciation during sample handling and storage is a prerequisite to obtaining reliable results of trace element speciation analysis. There is no comprehensive information on the stability of common arsenic species, such as inorganic arsenite [As(III)], arsenate [As(V)], monomethylarsonic acid, dimethylarsinic acid, and arsenobetaine, in human urine. Methods: We compared the effects of the following storage conditions on the stability of these arsenic species: temperature (25, 4, and −20 °C), storage time (1, 2, 4, and 8 months), and the use of additives (HCl, sodium azide, benzoic acid, benzyltrimethylammonium chloride, and cetylpyridinium chloride). HPLC with both inductively coupled plasma mass spectrometry and hydride generation atomic fluorescence detection techniques were used for the speciation of arsenic. Results: We found that all five of the arsenic species were stable for up to 2 months when urine samples were stored at 4 and −20 °C without any additives. For longer period of storage (4 and 8 months), the stability of arsenic species was dependent on urine matrices. Whereas the arsenic speciation in some urine samples was stable for the entire 8 months at both 4 and −20 °C, other urine samples stored under identical conditions showed substantial changes in the concentration of As(III), As(V), monomethylarsonic acid, and dimethylarsinic acid. The use of additives did not improve the stability of arsenic speciation in urine. The addition of 0.1 mol/L HCl (final concentration) to urine samples produced relative changes in inorganic As(III) and As(V) concentrations. Conclusions: Low temperature (4 and −20 °C) conditions are suitable for the storage of urine samples for up to 2 months. Untreated samples maintain their concentration of arsenic species, and additives have no particular benefit. Strong acidification is not appropriate for speciation analysis.

1998 ◽  
Vol 44 (3) ◽  
pp. 539-550 ◽  
Author(s):  
Mingsheng Ma ◽  
X Chris Le

Abstract We developed and evaluated a method for the determination of μg/L concentrations of individual arsenic species in urine samples. We have mainly studied arsenite [As(III)], arsenate [As(V)], monomethylarsonic acid (MMAA), and dimethylarsinic acid (DMAA) because these are the most commonly used biomarkers of exposure by the general population to inorganic arsenic and because of concerns over these arsenic species on their toxicity and carcinogenicity. We have also detected five unidentified urinary arsenic species resulting from the metabolism of arsenosugars. We combined ion pair liquid chromatography with on-line hydride generation and subsequent atomic fluorescence detection (HPLC/HGAFS). Detection limits, determined as three times the standard deviation of the baseline noise, are 0.8, 1.2, 0.7, and 1.0 μ/L arsenic for arsenite, arsenate, MMAA, and DMAA, respectively. These correspond to 16, 24, 14, and 20 pg of arsenic, respectively, for a 20-μL sample injected for analysis. The excellent detection limit enabled us to determine trace concentrations of arsenic species in urine samples from healthy subjects who did not have excess exposure to arsenic. There was no need for any sample pretreatment step. We used Standard Reference Materials, containing both normal and increased concentrations of arsenic, to validate the method. Interlaboratory studies with independent techniques also confirmed the results obtained with the HPLC/HGAFS method. We demonstrated an application of the method to the determination of arsenic species in urine samples after the ingestion of seaweed by four volunteers. We observed substantial increases of DMAA concentrations in the samples collected from the volunteers after the consumption of seaweed. The increase of urinary DMAA concentration is due to the metabolism of arsenosugars that are present in the seaweed. Our results suggest that the commonly used biomarkers of exposure to inorganic arsenic, based on the measurement of arsenite, arsenate, MMAA, and DMAA, are not reliable when arsenosugars are ingested from the diet.


2021 ◽  
Vol 42 (5) ◽  
Author(s):  
Huiling Li

Clinimetallomics is proposed as a branch of metallomics that focuses on the study of the metallome in clinical samples of urine, blood, and tissues. As the clinical diagnosis of arsenic poisoning is mainly based on the concentration of total arsenic in urine, the toxicity of arsenic varies greatly in different speciation. Analysis of arsenic speciation with excessive total arsenic in urine can provide a basis for precise treatment. It can also be used to understand the fate of arsenic in the body of patients with arsenic poisoning after treatment with sodium dimercaptopropane sulfonate. In this study, a HPLC-ICP-MS method was established for the determination of arsenic species in urine samples from patients diagnosed with arsenism. Use the established method to detect urine samples, which can be directly assayed after simple sample dilution with 20 mmol/L EDTA-2Na. With the concentration of arsenic speciation in the range of 1.0~100.0 ng/mL, the linear correlation coefficient was higher than 0.99996. The recoveries were between 92.4% and 109.0%. The precision of the concentration and retention time (n = 3) were less than 3.0% and 0.3%, respectively, and the detection limit was between 1.42 ng/mL and 1.86 ng/mL. This method can be applied to arsenic speciation in the urine of healthy people, in patients treated for arsenic poisoning, and in patients diagnosed with arsenism.


2018 ◽  
Vol 30 (6) ◽  
pp. 887-893
Author(s):  
Thanikul Srithunyarat ◽  
Anna Svensson ◽  
Sofia Hanås ◽  
Odd V. Höglund ◽  
Ragnvi Hagman ◽  
...  

Catecholamines can be used to evaluate neuroendocrine tumors, stress, and potentially pain, but catecholamines degrade rapidly. Their metabolites normetanephrine (NME) and metanephrine (ME) have better stability in urine. In cats, urine sampling in a home environment would be beneficial to reduce effects of clinical stress and simplify sampling. We evaluated a human urine ELISA for analysis of NME and ME in feline urine, and investigated the effects of acidification, cat tray pellets, and storage time at room temperature up to 8.5 h. In 26 feline urine samples, mean NME concentration was 192 ± 80 ng/mL, mean intra- and inter-assay CV was 6.5% and 4.2%, respectively, and spike recovery was 98–101%, but dilutional recovery was unsatisfactory. For ME, mean intra- and inter-assay CV was 10.2% and 4.1%, respectively. Mean urine ME concentration was 32.1 ± 18.3 ng/mL, close to the kit’s lowest standard, and spike recovery was 65–90%; the ELISA could not be validated for ME. The stability study, performed for NME on 12 urine samples, did not identify differences between acidified and non-acidified samples, cat tray pellets, or storage time, and no interaction effects. The ME ELISA was not suitable for feline urine; performance of the NME ELISA was acceptable, except for dilution recovery. For analysis of NME, feline urine can be sampled at home using cat tray pellets and stored at room temperature up to 8.5 h without acidification.


1985 ◽  
Vol 4 (2) ◽  
pp. 203-214 ◽  
Author(s):  
M.A. Lovell ◽  
J.G. Farmer

Trends in the urinary concentrations of the four arsenic species, pentavalent [As (V)] and trivalent [As (III)] inorganic arsenic, monomethylarsonic acid (MMAA) and dimethylarsinic acid (DMAA), were followed for several days subsequent to the acute intoxication of two human subjects by arsenic trioxide [As (III)2O3] and sodium orthoarsenate [Na2HAs(V)O4.7H2O], respectively, in unsuccessful suicide attempts. Total arsenic concentrations ranged from 1.6 to 18.7 mg/l. The increasing predominance of the less toxic methylated species, especially DMAA, after 3 or 4 days supports the concept of methylation as a natural detoxification mechanism as part of an overall reduction/methylation sequence involved in the biotransformation of inorganic arsenic by the human body. However, the additional possibility of oxidation of As(III) to As(V) in vivo under extreme immediate postingestion conditions is suggested by initial high urinary As(V) after arsenic trioxide intoxication. Relative proportions of As(V), As(III), MMAA and DMAA in both cases probably reflect species-dependent differences in rates of direct elimination and reactivity with tissues as well as the efficiency of methylation.


2008 ◽  
Vol 54 (1) ◽  
pp. 163-171 ◽  
Author(s):  
Chungang Yuan ◽  
Xiufen Lu ◽  
Nicole Oro ◽  
Zhongwen Wang ◽  
Yajuan Xia ◽  
...  

Abstract Background: Determination of arsenic species in saliva is potentially useful for biomonitoring of human exposure and studying arsenic metabolism. Arsenic speciation in saliva has not been reported previously. Methods: We separated arsenic species in saliva using liquid chromatography (LC) and quantified them by inductively coupled plasma mass spectrometry. We further confirmed the identities of arsenic species by LC coupled with electrospray ionization tandem mass spectrometry. These methods were successfully applied to the determination of arsenite (AsIII), arsenate (AsV), and their methylation metabolites, monomethylarsonic acid (MMAV), and dimethylarsinic acid (DMAV), in >300 saliva samples collected from people who were exposed to varying concentrations of arsenic. Results: The mean (range) concentrations (μg/L) in the saliva samples from 32 volunteers exposed to background levels of arsenic were AsIII 0.3 [not detectable (ND) to 0.7], AsV 0.3 (ND to 0.5), MMAV 0.1 (ND to 0.2), and DMAV 0.7 (ND to 2.6). Samples from 301 people exposed to increased concentrations of arsenic in drinking water showed detectable AsIII in 99%, AsV in 98%, MMAV in 80%, and DMAV in 68% of samples. The mean (range) concentrations of arsenic species in these saliva samples were (in μg/L) AsIII 2.8 (0.1–38), AsV 8.1 (0.3–120), MMAV 0.8 (0.1–6.0), and DMAV 0.4 (0.1–3.9). Saliva arsenic correlated with drinking water arsenic. Odds ratios for skin lesions increased with saliva arsenic concentrations. The association between saliva arsenic concentrations and the prevalence of skin lesions was statistically significant (P <0.001). Conclusions: Speciation of AsV, AsIII, MMAV, and DMAV in human saliva is a useful method for monitoring arsenic exposure.


Environments ◽  
2020 ◽  
Vol 7 (9) ◽  
pp. 68
Author(s):  
Min-hyuk Kim ◽  
Junseob Kim ◽  
Chang-Hyun Noh ◽  
Seogyeong Choi ◽  
Yong-Sung Joo ◽  
...  

Seaweed, a popular seafood in South Korea, has abundant dietary fiber and minerals. The toxicity of arsenic compounds is known to be related to their chemical speciation, and inorganic arsenic (iAs) is more detrimental than other species. Due to the different toxicities of the various chemical forms, speciation analysis is important for evaluating arsenic exposure. In this study, total arsenic (tAs) and six arsenic species (arsenite, arsenate, monomethylarsonic acid, dimethylarsinic acid, arsenobetaine, and arsenocholine) were analyzed in 180 seaweed samples. Although there were differences between seaweed species, the concentration of tAs was detected at levels ranging from 1 to 100 µg/g, and the distribution of six arsenic species differed depending on the seaweed species. No correlation between the concentration of iAs and tAs was found in most seaweed species. Through statistical clustering, hijiki and gulfweed were seen to be the seaweeds with the highest ratios of iAs to tAs. Using the iAs concentration data from the arsenic speciation analysis, a risk assessment of seaweed intake in South Korea was conducted. The margin of exposure values showed no meaningful risk for the general population, but low levels of risk were identified for seaweed consumers, with high intakes of gulfweed and hijiki.


2000 ◽  
Vol 46 (11) ◽  
pp. 1781-1786 ◽  
Author(s):  
Jun Yoshinaga ◽  
Amit Chatterjee ◽  
Yasuyuki Shibata ◽  
Masatoshi Morita ◽  
John S Edmonds

Abstract Background: Chemical speciation analysis is essential for the biological monitoring of inorganic arsenic exposure using urine as indicator medium. There is increasing demand for a certified reference material (CRM) of urine matrix for arsenic speciation. Methods: Urine (10 L) was collected from non-occupationally exposed Japanese males. We prepared 954 bottles of urine, each containing ∼10 mL, after filtering and blending the urine stock. The urine in each bottle was freeze-dried. Between-bottle homogeneity was confirmed by measuring the concentrations of selected minor and trace elements in the material and subsequent statistical analysis. Certification was based on a collaborative analysis involving 15 laboratories. Results: Certified values were determined for arsenobetaine (0.069 ± 0.012 mg As/L), dimethylarsinic acid (0.036 ± 0.009 mg As/L), and total arsenic (0.134 ± 0.011 mg/L) as well as for total selenium (0.059 ± 0.005 mg/L) and zinc (0.62 ± 0.05 mg/L), based on the analytical values from the collaborating laboratories. Reference values are given for copper (0.010 mg/L) and lead (0.0011 mg/L), based on definitive analysis at the National Institute for Environmental Studies (NIES). Conclusions: The present CRM, NIES CRM No. 18 Human Urine, is the first human urine CRM for arsenic speciation and will be of value for analytical quality assurance of the biological monitoring of arsenic exposure.


2004 ◽  
Vol 87 (1) ◽  
pp. 233-237 ◽  
Author(s):  
Aleksandra Polatajko ◽  
Joanna Szpunar

Abstract A method was developed for speciation analysis of arsenic in chicken meat. Different procedures were optimized for the recovery of arsenic compounds without destroying the original compounds, and 2 anion-exchange liquid chromatography columns were compared for the separation of arsenic species prior to on-line detection by inductively coupled plasma-mass spectrometry. The 2 species found were dimethylarsinic acid (106 ± 5 ng/g) and arsenobetaine (37 ± 4 ng/g). The stability of arsenic species in a chicken meat candidate reference material for at least 12 months was demonstrated.


2012 ◽  
Vol 9 (1) ◽  
pp. 55 ◽  
Author(s):  
Heléne Österlund ◽  
Mikko Faarinen ◽  
Johan Ingri ◽  
Douglas C. Baxter

Environmental contextBoth the mobility and toxicity of arsenic in natural waters are related to the aqueous species distribution. Passive sampling using ferrihydrite-backed diffusive gradients in thin films (DGT) devices has in previous studies been characterised to measure labile inorganic arsenic, and the possible contribution of organic species has been disregarded. This study shows that the two most prevalent organic arsenic species might be included in DGT measurements, which should be taken into consideration when evaluating DGT data in future studies. AbstractIn previous publications discussing arsenic determination using ferrihydrite-backed diffusive gradients in thin films (DGT) devices, organic arsenic forms have been disregarded, even though it is known that the two most prevalent in natural waters, dimethylarsinate (DMA) and monomethylarsonate (MMA), may adsorb to ferrihydrite and thereby be included in the measurement. In this work the accumulation of DMA and MMA, as well as inorganic arsenite and arsenate, to ferrihydrite-backed DGT devices was investigated. It could be demonstrated that MMA, and under acidic conditions also DMA, adsorbed to the binding layer and might therefore contribute to the total mass of measured arsenic. Diffusion coefficients were measured for all four species to enable quantification of DGT-labile concentrations of organic and inorganic arsenic. Elution of the analytes from the ferrihydrite binding layer was performed using 1 mL of 1 M NaOH to facilitate arsenic speciation analysis using chromatographic separation. Average recovery rates were between 87 and 108 %. This study shows that the contribution of DMA and MMA to the total accumulated mass must be taken into consideration when evaluating DGT data in future studies.


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