Enabling Emergency Response to Arsenic Contamination: Simultaneous and Rapid Identification of Arsenic Speciation by a Machine Learning-Driven Fluorescent Sensor Array.

BackgroundArsenic is an ubiquitous element linked to carcinogenicity, neurotoxicity, as well as adverse respiratory, gastrointestinal, hepatic, and dermal health effects.ObjectiveIdentify dietary sources of speciated arsenic: monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA).MethodsAge-stratified, sample-weighted regression of NHANES (National Health and Nutrition Examination Survey) 2003–2010 data (∼8,300 participants ≥6 years old) characterized the association between urinary arsenic species and the additional mass consumed of USDA-standardized food groups (24-hour dietary recall data), controlling for potential confounders.ResultsFor all arsenic species, the rank-order of age strata for median urinary molar concentration was children 6–11 years > adults 20–84 years > adolescents 12–19 years, and for all age strata, the rank-order was DMA > MMA. Median urinary molar concentrations of methylated arsenic species ranged from 0.56 to 3.52 µmol/mol creatinine. Statistically significant increases in urinary arsenic species were associated with increased consumption of: fish (DMA); fruits (DMA, MMA); grain products (DMA, MMA); legumes, nuts, seeds (DMA); meat, poultry (DMA); rice (DMA, MMA); rice cakes/crackers (DMA, MMA); and sugars, sweets, beverages (MMA). And, for adults, rice beverage/milk (DMA, MMA). In addition, based on US (United States) median and 90th percentile consumption rates of each food group, exposure from the following food groups was highlighted: fish; fruits; grain products; legumes, nuts, seeds; meat, poultry; and sugars, sweets, beverages.ConclusionsIn a nationally representative sample of the US civilian, noninstitutionalized population, fish (adults), rice (children), and rice cakes/crackers (adolescents) had the largest associations with urinary DMA. For MMA, rice beverage/milk (adults) and rice cakes/crackers (children, adolescents) had the largest associations.

Effect of cysteine on the speciation of arsenic by using hydride generation atomic absorption spectrometry

Arsenic.

Parenteral administration of arsenic trioxide has recently been recognized as an effective antineoplastic therapy, especially for the treatment of acute promyelocytic leukemia. Its efficacy and toxicity are concentration-dependent and are related to the fractions of different arsenic species and the degree of methylation. In this study, arsenic trioxide was given parenterally to rabbits as a single dose or as a daily dose (0.2, 0.6, and 1.5 mg/kg) for 30 days. The blood and organ concentrations of the arsenic species, including As(III), dimethylarsinic acid (DMA), and monomethylarsonic acid (MMA), were studied on day 1 (single-dose study), day 30 (multiple dosing study), and day 60 (reversibility study). As(III) was the major detectable arsenic species in the blood. The pharmacokinetic parameters (total clearance, area under the curve, etc.) for As(III) indicated a limit for the capacity to eliminate As(III) at the dose of 1.5 mg/kg, and were quite the same after a single dose or chronic multiple dosing. In tissues, DMA was found to be the major metabolite and the concentrations of DMA, As(III), and MMA in general increased with the dose, with the increase most significant at a dose of 1.5 mg/kg. However, normalized tissue distribution of As(III) in the kidney on day 1, but not on day 30, was nonlinear. Along with decreased levels of As(III) and increased levels of DMA, an inducible capacity for methylating As(III) to DMA after chronic dosing in kidney was suggested. The tissue concentration of DMA was highest in lung and liver, and the normalized tissue distributions in liver on day 30 were nonlinear, suggesting a limit in eliminating DMA after a chronic high load of As(III). Tissue concentrations of As(III), DMA, and MMA in bladder increased dramatically after chronic dosing. However, after washout for 30 days, As(III), DMA, and MMA were all undetectable in bladder and liver. However, As(III) in hair and low levels of DMA in lung, kidney, heart and hair were still detected. In conclusion, in rabbits we found a similar pharmacological profile after a single dose or chronic multiple dosing of parenteral arsenic trioxide, with a limiting metabolizing capacity at a dose of 1.5 mg/kg. Tissue accumulation of arsenic species, mainly DMA, and its reversibility after washout were tissue-selective. The potential for late toxicities of arsenic trioxide in organs with a significant tendency for arsenic accumulation with low reversibility should be closely monitored.

The objective of this study was to report on the arsenic species present in tube‐well water samples collected from West Bengal, India, especially dimethylarsinic acid (DMA) and monomethylarsonic acid (MMA), whose existence has not been reported in the literature. The water samples were collected from Jalangi Gram Panchayet (Murshidabad district, West Bengal, India). The samples were speciated for arsenic 11 days after collection. The samples were collected in duplicate. One part was acidified with nitric acid (final concentration 0.1%), whereas the other part was left unacidified. A quick and highly sensitive high‐performance liquid chromatography–inductively coupled plasma mass spectrometry (HPLC–ICPMS) technique was employed for the separation and detection of the arsenic species. Four arsenic species, namely arsenite [arsenic(III)], DMA, MMA and arsenate [arsenic(V)] were separated and analysed in less than 5 min. Total arsenic concentration was determined by flow injection (FI)‐ICPMS. Most of the samples were found to contain low concentrations of DMA and MMA (<2.1 ppb) and high concentrations of inorganic arsenic (>300 ppb). The existence of DMA and MMA in both acidified and unacidified water samples and in similar concentrations suggests that their presence is natural and not due to acidification. The detection limit of the four arsenic species was 0.06–0.10 ppb. The method was validated by spike recovery and analysis of two water standard reference materials (SRMs). The percentage recoveries of added spikes of all four species were 97–112%. The total arsenic concentration obtained by FI‐ICPMS and the sum of the four arsenic species obtained by HPLC–ICPMS for the two water SRMs agreed with the certified values. Moreover, the difference between the total arsenic and the sum of the four arsenic species for most of the water samples was less than 10%. Copyright © 2002 John Wiley & Sons, Ltd.

Arsenic speciation in environmental and biological samples: Extraction and stability studies

ABSTRACTBackground:Arsenic trioxide (ATO) is widely applied to treat acute promyelocytic leukemia (APL). To elucidate metabolism and toxicity of arsenic, we analyzed time course of arsenic species in red blood cells (RBCs) of APL patients.Methods:Nine APL patients received ATO (0.16 mg/kg/day) through 18-h infusion. Blood was collected before daily administration (days 2 to 9), and at different time points on day 8. Inorganic arsenic (iAs), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA) were detected by HPLC-ICP-MS.Results:Arsenic species reached Cmax at 18 h on day 8. Arsenicals gradually accumulated during days 2 to 9, whereas their percentages remained almost constant. The general trend in red blood cells (RBCs) was iAs > MMA > DMA. MMA was consistently the predominant methylated arsenic metabolite in RBCs. iAs, MMA, and tAs (tAs = iAs + DMA + MMA) concentrations (P < 0.0001), MMA/DMA ratios (P = 0.0016) and iAs% (P = 0.0013) were higher in RBCs than in plasma.Conclusions:Time course of arsenic species reveal kinetic characteristic of ATO metabolites in RBCs. Arsenic species accumulated with administration frequency. Arsenic species in RBCs were remarkably different from those in plasma. Time course of arsenic species in RBCs is important in ATO clinical application.

Arsenic speciation in freshwater fish using high performance liquid chromatography and inductively coupled plasma mass spectrometry.

Arsenic (As) speciation in surface and groundwater from two provinces in Argentina (San Juan and La Pampa) was investigated using solid phase extraction (SPE) cartridge methodology with comparison to total arsenic concentrations. A third province, Río Negro, was used as a control to the study. Strong cation exchange (SCX) and strong anion exchange (SAX) cartridges were utilised in series for the separation and preservation of arsenite (As(III)), arsenate (As(V)), monomethylarsonic acid (MA(V)) and dimethylarsinic acid (DMA(V)). Samples were collected from a range of water outlets (rivers/streams, wells, untreated domestic taps, well water treatment works) to assess the relationship between total arsenic and arsenic species, water type and water parameters (pH, conductivity and total dissolved solids, TDS). Analysis of the waters for arsenic (total and species) was performed by inductively coupled plasma mass spectrometry (ICP-MS) in collision cell mode. Total arsenic concentrations in the surface and groundwater from Encon and the San José de Jáchal region of San Juan (north-west Argentina within the Cuyo region) ranged from 9 to 357μgl(-1) As. Groundwater from Eduardo Castex (EC) and Ingeniero Luiggi (LU) in La Pampa (central Argentina within the Chaco-Pampean Plain) ranged from 3 to 1326μgl(-1) As. The pH range for the provinces of San Juan (7.2-9.7) and La Pampa (7.0-9.9) are in agreement with other published literature. The highest total arsenic concentrations were found in La Pampa well waters (both rural farms and pre-treated urban sources), particularly where there was high pH (typically > 8.2), conductivity (>2,600 μS cm(-1)) and TDS (>1,400mgl(-1)). Reverse osmosis (RO) treatment of well waters in La Pampa for domestic drinking water in EC and LU significantly reduced total arsenic concentrations from a range of 216-224μgl(-1) As to 0.3-0.8μgl(-1) As. Arsenic species for both provinces were predominantly As(III) and As(V). As(III) and As(V) concentrations in San Juan ranged from 4-138μgl(-1) to <0.02-22μgl(-1) for surface waters (in the San José de Jáchal region) and 23-346μgl(-1) and 0.04-76μgl(-1) for groundwater, respectively. This translates to a relative As(III) abundance of 69-100% of the total arsenic in surface waters and 32-100% in groundwater. This is unexpected because it is typically thought that in oxidising conditions (surface waters), the dominant arsenic species is As(V). However, data from the SPE methodology suggests that As(III) is the prevalent species in San Juan, indicating a greater influence from reductive processes. La Pampa groundwater had As(III) and As(V) concentrations of 5-1,332μgl(-1) and 0.09-592μgl(-1) for EC and 32-242μgl(-1) and 30-277μgl(-1) As for LU, respectively. Detectable levels of MA(V) were reported in both provinces up to a concentration of 79μgl(-1) (equating to up to 33% of the total arsenic). Previously published literature has focused primarily on the inorganic arsenic species, however this study highlights the potentially significant concentrations of organoarsenicals present in natural waters. The potential for separating and preserving individual arsenic species in the field to avoid transformation during transport to the laboratory, enabling an accurate assessment of in situ arsenic speciation in water supplies is discussed.

A sensitive and robust method for the determination of eight inorganic and organic arsenic species by ion-exclusion liquid chromatography combined with inductively coupled plasma mass spectrometry (LC-ICP-MS) and LC-hydride generation-ICP-MS (LC-HG-ICP-MS) is described. The species are arsenite (AsIII), arsenate (AsV), monomethylarsonic acid (MMAs), dimethylarsinic acid (DMAs), arsenobetaine (AsB), trimethylarsine oxide (TMAsO), tetramethylarsonium salt (TMAs) and arsenocholine salt (AsC). A good separation of seven arsenic species, AsIII, AsV, MMAs, DMAs, AsB, TMAsO, and AsC or TMAs, was achieved by using an ion-exclusion column packed with a carboxylated methacrylate resin and 0.35 mmol l−1 of a sodium sulfate solution adjusted to pH 3.8 as the mobile phase. The detection limits of the eight arsenic species obtained by LC-ICP-MS ranged from 0.067 to 0.34 ng As ml−1 using an injection volume of 50 µl. A hydride generation technique improved the detection limits of AsIII, AsV, MMAs, DMAs and TMAsO to 0.016–0.075 ng As ml−1, while AsB, TMAs and AsC were not detectable. The relative standard deviations of five replicates of a standard of each arsenic species by the former method ranged from 1.3 to 3.3% and those by the latter method, from 1.8 to 3.1%. The proposed methods were successfully applied to the determination of five arsenic species in human urine and six species in an extract from tuna fish tissue. The only necessary pretreatment for these analyses involved filtration with a 0.45 µm membrane and the ArCl polyatomic interference, due to a large amount of chloride in the biological samples on 75As measurement, was eliminated by the described LC separation. In addition, serious deterioration in column performance and a decrease in the sensitivity of ICP-MS were not observed during the experimental period of five months. The LC-ICP-MS and LC-HG-ICP-MS methods were validated by analyzing reference samples of human urine and tuna fish tissue.

A dual column packed with a magnetic metal-organic framework composite (MFC) and mercapto-functionalized MFC nanoparticles (MFC-SH) in microfluidic chip channels is described for array chip-based magnetic solid phase microextraction of arsenic species including arsenite [As(III)], arsenate [As(V)], monomethylarsonous acid (MMA) and dimethylarsinic acid (DMA) in SCC-7 cells. At pH6, the MFC-SH adsorbs As(III) while MFC quantitatively adsorbs As(V), DMA and MMA. The As(III) adsorbed on the MFC-SH can be desorbed with a 2% solution of thiourea in 0.5M HNO3. The arsenic species MMA, DMA and As(V) are retained on the MFC but can be desorbed by ammonia. A sequential elution strategy was employed to elute MMA, DMA, As(V) and As(III) one by one for subsequent on-line determination by ICP-MS. The limits of detection are 4.8, 6.3, 3.8 and 7.1ngL-1 for As(V), DMA, MMA and As(III), respectively. The enrichment factors are between 23 and 25, and the throughput is 7 samples per hour. The arsenic species in (spiked) SCC-7 cell samples were analyzed by the online system with adequate recoveries (89-110%). Graphical abstractSchematic representation of magnetic metal-organic framework composite (MFC) and mercapto-functionalized MFC nanoparticles (MFC-SH) packed dual-column, squamous carcinoma cells (SCC-7), online chip-based array MSPME-ICPMS system. Cell lysis units (blue), Microextraction units (black), Microvalves (green), Outlet (black), Permanent magnets (gray), Intet (red/purple/yellow).

Arsenic contamination of groundwater and associated medical problems have long been reported in the Mushidabad district, one of nine arsenic‐affected districts in West Bengal, India. In order to estimate people's total exposure to arsenic, we visited 12 arsenic‐affected families in that area during 4–7 December 2000 and collected seven tubewell waters used for drinking, cooking and other household purposes and 51 urine samples from those families. The arsenic concentrations in drinking water ranged from 2.7 to 170 ppb. Those families designated A–E, G–I and J took in arsenic concentrations of 72.6 ppb, 154 ppb and 170 ppb respectively. The concentrations of arsenite, arsenate, monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA) in urine (corrected for creatinine level in the urine), obtained from 51 persons, ranged from 0 to 796.9 ppb (mg creatinine/ml urine)−1, from 0 to 1635.2 ppb (mg creatinine/ml urine)−1, from 2.1 to 411.0 ppb (mg creatinine/ml urine)−1 and from 8.3 to 2017.5 ppb (mg creatinine/ml urine)−1 respectively. The average concentration of total arsenic was 59.2 ppb (mg creatinine/ml urine)−1. On comparison of the ratios of (MMA + DMA) to total arsenic, the average proportion of (MMA + DMA) was 83.2%, but the proportions were 27.3% and 16.5% for two of the children (2 years old and 13 years old respectively). This result suggested that they might be damaged due to the methylating capacity. When estimating arsenic species in urine obtained from families A–E, G–I and J, these family members normally metabolized the inorganic arsenic to MMA and DMA and eliminated these as such in comparison with an intake of inorganic arsenic from the tubewell water. The arsenic species in urine from people having the same food and life habits showed the same profile in both men and women. There was a good correlation (p &lt; 0.05) between the ages of 19 persons in families A–E and the values of (MMA + DMA) or total arsenic in urine. Copyright © 2002 John Wiley &amp; Sons, Ltd.

Selective separation of arsenic species from aqueous solutions with immobilized macrocyclic material containing solid phase extraction columns

Speciation analysis of arsenic and selenium compounds in environmental and biological samples by ion chromatography–inductively coupled plasma dynamic reaction cell mass spectrometer

An on-line and fully automated method was developed for the continuous and dynamic in vivo monitoring of four arsenic species [arsenite (AsIII), arsenate (AsV), monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA)] in urine of living organisms. In this method a microdialysis sampling technique was employed to couple on-line with high performance liquid chromatography (HPLC) and hydride generation atomic absorption spectrometry (HGAAS). Dialysates perfused through implanted microdialysis probes were collected with a sample loop of an on-line injector for direct and automated injection into HPLC system hyphenated with HGAAS. The saline (0.9% NaCl) solution was perfused at the rate of 1 microl min(-1) through the microdialysis probe and the dialysate was loaded into 50 microl of sample loop. The separation conditions were optimally selected to be in phosphate buffer solution at a pH 5.2 with a flow rate of 1.2 ml min(-1). The effluent from the HPLC was first mixed on-line at the exit of the column with HCl (1 M) solution and then mixed with a NaBH4 (0.2% m/v) solution. Based on the optimal conditions obtained, linear ranges of 2.5-50 ng ml(-1) for AsIII and 6.75-100 ng ml(-1) for the other three arsenic species were obtained. Detection limits of 1.00, 2.18, 1.03 and 2.17 ng ml(-1) were obtained for AsIII, DMA, MMA and AsV, respectively. Typical precision values of 3.4% (AsIII), 5.4% (DMA), 3.6% (MMA) and 7.5% (AsV) were obtained, respectively, at a 25 ng ml(-1) level. Recoveries close to 100%, relative to an aqueous standard, were observed for each species. The average in vivo recoveries of AsIII, DMA, MMA and AsV in rat bladder urine were 56+/-5%, 60+/-9%, 49+/-3% and 55+/-7%, respectively. The use of an on-line microdialysis-HPLC-HGAAS system permitted the determination of four urinary arsenic species in the bladder of an anesthetized rat with a temporal resolution of 50 min sampling.