Itemized determination of As, Sb, Bi, Se, and Ge in graphite sample by HG-AFS with high-temperature microwave digestion.

In this paper, we optimized a method for fast and accurate determination of five impurity elements (As, Sb, Bi, Se, and Ge) in graphite samples to overcome the shortcomings of existing methods, such as complicated equipment, cumbersome process, multiple-time preparation, separate determination, and large error in results. Graphite samples were digested with HNO3-H2SO4-HClO4-HF in a high-temperature and high-pressure microwave digestion apparatus, and the elements were extracted and determined separately by AFS (atomic fluorescence spectrometry). There is no element loss during the processing and analysis of this method. The spike recoveries (As: 90.30%-102.3%, Sb: 90.73%-110.0%, Bi: 90.00%-99.67%, Se: 93.33%-110.0%, Ge: 92.26%-104.2%) and precision (RSD%; As: 1.34%-8.96%, Sb: 2.67%-7.10%, Bi: 1.83%-4.58%, Se: 0.36%-3.25%, Ge: 4.41%-8.65%) meet the requirements of the corresponding quality specifications. The method has some advantages (such as no elemental loss, fast testing, strong element targeting, and accurate results), and thus can achieve batch determination of graphite samples. The optimized method for graphite sample and final solution preparations can be used for diverse spectrometric technologies, and that for spectrometer conditions have reference value for HG-AFS instruments.

Comparative pharmacokinetics and urinary excretion of arsenic and mercury after oral administration of realgar, cinnabar and AnGongNiuHuang Pill to rats.

Realgar- and cinnabar-containing AnGongNiuHuang Pill (AGNHP) is widely used for treating encephalopathy syndrome. However, it raises great safety concerns due to the adverse effects reported by arsenic or mercury poisoning. Although AGNHP has been generally recognized, little is known about the metabolism of arsenic and mercury and their resulting potential health risk in vivo. Thus, comparative pharmacokinetics and urinary excretion of arsenic and mercury were conducted in rats after oral administration of realgar, cinnabar and AGNHP, respectively. The contents of arsenic and mercury in rat blood and urine were determined by hydride-generation atomic fluorescence spectrometry (HG-AFS) after wet digestion. AGNHP significantly reduced the absorption of arsenic in blood and promoted urinary arsenic excretion. Whereas, it increased the blood mercury absorption and reduced urinary mercury excretion. No significant toxicity was observed in the clinical dose range of AGNHP. However, excessive exposure to arsenic and mercury may still pose risks especially by long-term or excessive medication. The results are helpful for the rational clinical applications of realgar- and cinnabar-containing TCMs.

Determination of arsenic in urine by hydride generation atomic fluorescence spectrometry with ammonium persulfate digestion / 中华地方病学杂志

Objective:To establish a hydride generation atomic fluorescence method using ammonium persulfate as the digestion reagent for determination of arsenic in urine (hereinafter referred to as this method).Methods:The collected urine samples with ammonium persulfate were heated and digested on the tubular electric heating automatic control constant temperature digester (60 holes), with 5% hydrochloric acid solution as reaction medium and current carrier and 1.5% potassium borohydride solution as reducing agent. Arsenic content was determined with a four-channel atomic fluorescence spectrometer. The arsenic standard solution of 0 - 10 μg/L was prepared to determine the standard curve of this method, and the method was evaluated from the detection limit, linear range, correlation coefficient, precision, standard addition recovery experiment, and urine arsenic quality control sample detection. The standard method "Determination of Arsenic in Urine by Hydride Generation Atomic Fluorescence Spectrometry" (WS/T 474-2015, referred to as the standard method) was used for comparison experiments.Results:When the sampling volume was 1 ml, the detection limit of this method (digest with 1 ml 1.5 mol/L ammonium persulfate) was 0.03 μg/L. In the range of arsenic content from 0 - 10 μg/L, the linear relationship between arsenic content and fluorescence intensity was good, and the correlation coefficients ( r) were all 0.999 9. The relative standard deviations( RSD) of the three replicates of urine samples with different concentrations were 1.00%, 0.89% and 0.49%, respectively. Urine arsenic quality control samples were tested, and the test results were all within the range of public values; the overall average recovery was 102.29%, and the recovery range was 92.10% - 108.15%. Compared with the standard method in the determination results of 20 urine samples, the difference was not statistically significant ( t = - 0.40, P > 0.05). Conclusions:The hydride generation atomic fluorescence spectrometry using ammonium persulfate as digestion reagent for the determination of arsenic in urine has the advantages of low detection limit, good precision, high accuracy, small amount of sampling and digestion reagent, simple operation, and less harmful gas generation in sample pretreatment. It is suitable for rapid determination of arsenic in urine in large quantities.

Ultrasound-assisted dual-cloud point extraction with high-performance liquid chromatography-hydride generation atomic fluorescence spectrometry for mercury speciation analysis in environmental water and soil samples.

A method for simultaneous preconcentration and determination of mercury species in water and soil samples was established using high-performance liquid chromatography with hydride generation atomic fluorescence spectrometry after ultrasound-assisted dual-cloud point extraction. The extraction process was divided into two steps. In the first cloud point extraction, inorganic mercury and methylmercury formed chelates with sodium diethyldithiocarbamate and were extracted into Triton X-114 micelles. In the second stage, a displacement reaction between sodium diethyldithiocarbamate-inorganic mercury/methylmercury and l-cysteine occurred, and the analytes entered the l-cysteine aqueous solution under ultrasonication. This aqueous solution was directly introduced to the high-performance liquid chromatography with hydride generation atomic fluorescence spectrometry and the detection was completed within 6 min. Under the optimum experimental conditions, the linear range was 0.10-5.0 µg/L (r ≥0.9993) for inorganic mercury and methylmercury, and the enhancement factors were 15.7 for inorganic mercury and 6.35 for methylmercury. The limits of detection for inorganic mercury and methylmercury were 0.004 and 0.016 µg/L, respectively. The approach was successfully applied to the determination of trace inorganic mercury and methylmercury in water and soil samples with good recoveries (85.3-110%). This method solved the problem of peak fusion of the two analytes and was successfully applied to the speciation analysis of mercury.

Arsenic-Related Health Risk Assessment of Realgar-Containing NiuHuangJieDu Tablets in Healthy Volunteers Po Administration.

Realgar, an arsenic-containing traditional Chinese medicine of As2S2, has significant therapeutic effects for hundreds of years. NiuHuangJieDu tablets (NHJDT) is one of the most commonly prescribed realgar-containing preparations for the treatment of sore throat, swelling, and aching of gums. However, realgar-containing TCMs raise great safety concerns due to the adverse effects reported by arsenic poisoning. In this study, the arsenic-related health risk assessment of NHJDT was conducted in healthy volunteers after single and multiple doses oral administration. Blood, plasma, and urine samples were collected after dosing at predetermined time points or periods. Simple, rapid, and sensitive methods were established for the quantification of total arsenic and arsenic speciation in biological samples. The total arsenic and arsenic speciation were determined by hydride generation-atomic fluorescence spectrometry (HG-AFS) and high-performance liquid chromatography-hydride generation-atomic fluorescence spectrometry (HPLC-HG-AFS), respectively. No significant fluctuation of total arsenic was observed in human blood, and no traces of arsenic speciation were found in human plasma. Dimethylarsenic acid was detected as the predominated arsenic species in human urine after dosing. Therapeutic dose administration of NHJDT was relatively safe in single dose for the limited blood arsenic exposure, but long-term medication may still pose health risks due to the accumulation of arsenics in blood and its extremely slow excretion rate. Therefore, arsenic exposure should be carefully monitored during realgar-containing TCM medication, especially for long-term regimen. The results obtained in this study will provide scientific references for the clinical application of realgar and its-containing TCMs.

Speciation analysis of arsenic in urine samples from APL patients treated with single agent As2O3 by HPLC-HG-AFS.

Arsenic trioxide [As2O3, arsenite (AsIII) in solution] has been applied successfully for the treatment of acute promyelocytic leukemia (APL). The arsenic speciation analysis of urine is critical to reveal the metabolic mechanism and the relationship between arsenic species and the clinical response. To characterize the arsenic species in urine, a simple and robust HPLC-HG-AFS method was developed and validated to quantify the levels of arsenic species [AsIII and its metabolites, monomethylarsonic acid (MMAV), dimethylarsinic acid (DMAV), and arsenate (AsV)] in urine samples from 66 patients with APL. Patients received As2O3 (0.16 mg/kg/day) via continuous slow-rate infusion or conventional infusion. Urine samples were collected at steady state before the start of the next daily administration. The relative proportions (median) of arsenic species in urine were: AsIII, 33.00% (IQR: 24.34%-46.82%); DMAV, 36.42% (IQR: 25.82%-51.98%); MMAV, 23.89% (IQR: 19.52%-27.19%); and AsV, 2.22% (IQR: 1.293%-3.665%). The levels and proportions of arsenic species vary widely among individual patients. DMAV and un-metabolized AsIII were the dominant arsenic compounds excreted from the urine of patients with APL treated with As2O3. AsV was the least abundant arsenic species in all urine samples. Good positive correlations were found between the levels and proportions of arsenic species in urine and those in plasma; thus, urinary arsenic can reflect the levels of arsenic in plasma. Urinary arsenic is a critical biomarker to evaluate the metabolism and toxicity of arsenic in the clinical application of As2O3.

Health risk assessment of arsenic in Realgar and NiuHuangJieDu Tablets based on pharmacokinetic study.

NiuHuangJieDu Tablets (NHJDT), a popular realgar (As4S4) containing patented traditional Chinese medicine (TCM), is widely used in the treatment of acute tonsillitis, pharyngitis, periodontitis and mouth ulcer. However, arsenic is considered as one of the most toxic elements, leading to growing concerns about the quality and safety of realgar-containing TCMs recently. In this study, health risk assessment of arsenic in realgar and NHJDT was conducted through oral administration of both substances to rats with single and multiple doses, respectively. The total blood arsenic concentration was used as the health risk indicator and determined by hydride generation-atomic fluorescence spectrometry after modified Kjeldahl digestion, and then applied to the pharmacokinetic study. For single oral dose study in rats, the low, medium, and high doses of realgar and NHJDT were set equivalent to 1, 5 and 20 times the human therapeutic dose (1.3 mg realgar/kg), respectively. Multiple doses were given at low and high dose levels every 12 h for seven consecutive days, respectively. Significant differences in the total blood arsenic pharmacokinetic profiles were observed between the corresponding realgar and NHJDT groups. These results indicated that NHJDT significantly reduced the total blood arsenic exposure present in realgar, and the detoxification mechanism might be attributed to herb-herb interactions in NHJDT. However, the accumulation of blood total arsenic was significant due to the long elimination half-life and high accumulation index in both realgar and NHJDT groups. Therefore, the potential health risk of arsenic caused by the administration of realgar-containing TCMs should be taken into account for excessive or long-term medication. Precautions should be taken for the clinical application of realgar-containing TCMs.

An automated continuous homogeneous microextraction for the determination of selenium and arsenic by hydride generation atomic fluorescence spectrometry.

An automated continuous homogeneous microextraction approach based on a flow system has been developed and coupled with a hydride generation atomic fluorescence spectrometry system (HG-AFS). The developed approach was applied for the determination of trace arsenic and selenium in environmental water and liver samples. The nonanoic acid was investigated as a switchable hydrophilicity solvent (SHS) for homogeneous microextraction of As(III) and Se(IV) complexes with pyrrolidinedithiocarbamate (PDC). The procedure involved on-line mixing ammonium PDC (aqueous phase), sodium nonanoate (aqueous phase) and acid sample solution resulting in the formation of SHS (nonanoic acid) dispersed into the acid aqueous phase. By this continuous process, analytes complexes with PDC were formed and extracted into the fine SHS droplets followed by retention into a monolithic column packed with block of porous PTFE. Finally, the retained complexes were eluted with NaOH solution and delivered to the HG-AFS system. The limits of detection, calculated from a blank test based on 3σ, were 0.01µgL-1 for both analytes.

A method for detection of selenium in grain by hydride generation-atomic fluorescence spectrometry and its application / 中华地方病学杂志

Objective To establish a rapid, simple and accurate method for detection of selenium in grain that is suitable in Chinese situation. Methods Nitric acid and perchloric acid(7: 3, v/v) were used to digest the grain samples by heating on a hot plate. Selenium was determined with hydride generation atomic fluorescence spectrometry. Sample detection limit, precision, accuracy(recovery, method characteristics and method control) were studied. And the grain samples of Shandong Province were determined by this method. Results The lowest detection limit was 4 μg/kg. The coefficient of correlation of working curve was 0.999 9. Intra-day precision was 1.32%, day precision was 4.17%. The total average rate of recovery was 100.5% with a range of 96.7% - 105.5%, and the average rates of recovery were 104.0%, 99.0% and 98.4% (n = 6). The determination results of corn reference material [(0.022 ± 0.006) mg/kg] were in the standard value range [(0.021 ± 0.008) mg/kg]. The determination results of the samples [(0.424 ± 0.096) mg/kg] were consistent with the results of national standard fluorescence method [(0.406 ± 0.108) mg/kg]. The contents of selenium in wheat, maize and sweet potato samples from five regions of Shandong Province were:Shanting:(0.030 3 ± 0.025 2),(0.016 8 ± 0.013 5),(0.015 4 ± 0.002 9) mg/kg; Anqiu:(0.020 3 ± 0.000 1), (0.020 4 ± 0.009 9), (0.017 1 ± 0.007 5) mg/kg; Ju'nan:(0.021 3 ± 0.013 9), (0.018 5 ± 0.007 8),(0.019 9 ± 0.003 6)mg/kg;Yishui:(0.025 7 ± 0.006 2),(0.020 6 ± 0.003 2), (0.018 2 ± 0.003 2) mg/kg; Wulian:(0.020 3 ± 0.004 7), (0.020 1 ± 0.008 9), (0.018 4 ± 0.007 3) mg/kg. Conclusions The method has the advantages of higher precision and accuracy, less time, less pollution, less aciduse, easier operation and repeatability.It is very suitable for measuring selenium content in large amount of food samples.

Determination of Total Arsenic and Arsenic Species in Blood of Acute Promyelocytic Leukemia Patients Treated with Arsenous Acid / 中国药师

Objective:To quantify the plasma concentrations of inorganic arsenic (As(III) and As(V)) and methylated metabo-lites ( MMA and DMA) , and to detect the total amount of arsenic in blood cells and plasma by high performance liquid chromatogra -phy-hydridegeneration-atomic fluorescence spectrometry ( HPLC-HG-AFS) and HG-AFS methods to clarify the arsenic species in acute promyelocytic leukemia (APL) patients.Methods:The blood cells and plasma were digested by the mixture of HNO 3-H2O2 and ana-lyzed by HG-AFS.For the arsenic species , the plasma samples were prepared with perchloric acid to precipitate protein .The superna-tant was separated on an anion-exchange column in 6 min with isocratic elution using 13 mmol · L-1 CH3 COONa, 3 mmol · L-1 NaH2 PO4 , 4 mmol· L-1 KNO3 and 0.2 mmol· L-1 EDTA-2Na.Results:The methods provided linear range of 0.2-20 ng· ml-1 for total arsenic and 2.0-50 ng· ml-1 for four arsenic species (r>0.9950).The spiked recoveries ranged from 81.2％to 108.6％, and the coefficients of variation for intra-and inter-batch precision were less than 9.3％and 12.5％, respectively.The developed methods were applied successfully in the assay of total arsenic and arsenic species in 5 APL patients.Conclusion:The method is simple, fast and accurate , which can be applied in the assay of arsenic compounds in plasma and blood cells in APL patients .

Quantitative Determination of Arsenic Species in Feed Using Liquid Chromatography-Hydride Generation Atomic Fluorescence Spectrometry / 分析化学

A sensitive and rapid method using liquid chromatography-hydride generation atomic fluorescence spectrometry (HPLC-HG-AFS) was developed for the simultaneous determination of seven arsenic species As3+, As5+,MMA, DMA, p-ASA, 4-OH and ROX in feeds. The isolation of the analytes from feed samples was accomplished using methanol water (1:1, V/V). The target compounds were separated on a PRP-X100 anion exchange column and then analyzed by HG-AFS. The mobile phase was 15 mmol/L (NH4)2HPO4and 10 mmol/L potassium acid phthalate. Good linearity was obtained for all of the seven arsenic species, with linear coefficients higher than 0.9964. The LODs of the seven arsenic species were between 5 and 30 μg/kg. Average recoveries for the seven analytes were in the ranges of 76.3%-108.1%, with intra- and inter-day repeatability lower than 7.7% and 17.4%,respectively. This validated method was successively applied to the determination of arsenic species in feed. This method was sensitive,simple,cheap and low operation cost,and could be used for the determination of the arsenicspecies in feeds.

HPLC-HG-AFS determination of arsenic species in acute promyelocytic leukemia (APL) plasma and blood cells.

Arsenic trioxide (ATO) has been successfully used in the treatment of acute promyelocytic leukemia (APL). To clarify the arsenic species in APL patients, high performance liquid chromatography-hydride generation-atomic fluorescence spectrometry (HPLC-HG-AFS) and HG-AFS methods were developed and validated to quantify the plasma concentrations of inorganic arsenic (As(III) and As(V)) and methylated metabolites (MMA and DMA), and the total amounts of arsenic in blood cells and plasma. Blood cells and plasma were digested with mixtures of HNO3H2O2 and analyzed by HG-AFS. For arsenic speciation, plasma samples were prepared with perchloric acid to precipitate protein. The supernatant was separated on an anion-exchange column within 6min with isocratic elution using 13mM CH3COONa, 3mM NaH2PO4, 4mM KNO3 and 0.2mM EDTA-2Na. The methods provided linearity range of 0.2-20ng/mL for total arsenic and 2.0-50ng/mL for four arsenic species. The developed methods for total arsenic and arsenic species determination were precise and accurate. The spiked recoveries ranged from 81.2%-108.6% and the coefficients of variation for intra- and inter-batch precision were less than 9.3% and 12.5%, respectively. The developed methods were applied successfully for the assay of total arsenic and arsenic species in 5 APL patients. The HPLC-HG-AFS may be a good alternative for arsenic species determination in APL patients with its simplicity and low-cost in comparison with HPLC-ICP-MS.

Determination of total selenium in food samples by d-CPE and HG-AFS.

A dual-cloud point extraction (d-CPE) procedure was developed for the simultaneous preconcentration and determination of trace level Se in food samples by hydride generation-atomic fluorescence spectrometry (HG-AFS). The Se(IV) was complexed with ammonium pyrrolidinedithiocarbamate (APDC) in a Triton X-114 surfactant-rich phase, which was then treated with a mixture of 16% (v/v) HCl and 20% (v/v) H2O2. This converted the Se(IV)-APDC into free Se(IV), which was back extracted into an aqueous phase at the second cloud point extraction stage. This aqueous phase was analyzed directly by HG-AFS. Optimization of the experimental conditions gave a limit of detection of 0.023µgL-1 with an enhancement factor of 11.8 when 50mL of sample solution was preconcentrated to 3mL. The relative standard deviation was 4.04% (c=6.0µgL-1, n=10). The proposed method was applied to determine the Se contents in twelve food samples with satisfactory recoveries of 95.6-105.2%.

[Exposure levels of lead, selenium, arsenic and mercury in brick-teas from main producing areas in China].

OBJECTIVE: To study the levels of Pb, Se, As and Hg in brick-teas from main producing areas in China and evaluate the safety. METHODS: A total of 31 samples of brick tea from seven provinces where minority nationalities were accustomed to drinking a large quantity of brick tea were collected, Pb concentrations were determined by inductively coupled plasma-mass spectrometry, and concentrations of As, Se, Hg were detected by hydride generation atomic fluorescence spectrometry. The data were analyzed by SPSS 22. 0 software. RESULTS: The average lead levels in brick tea was 6. 232 mg/kg, which exceeded the limit standard of GB 2762-2012. There was a great difference of Pbconcentrations among the various kinds of brick tea producing in different provinces, and the lower Pb concentrations detected in Tuo tea and Puerh tea producing in Yunnan Province, was 1. 337 mg/kg, and the highest determined in Kang brick producing in Sichuan Province, was 9. 998 mg/kg. In addition, the concentrations of As and Hg were all below the limit standard of NY 659-2003. For people accustomed to drinking brick tea for a long term, the average intake amounts of Pb, As, Hg through brick tea contributed 13. 63%, 1. 71% and 0. 29% to dietary Pb, As, Hg of the provisional tolerable weekly intake( PTWI) recommended by Joint FAO/WHO Expert Committee of Food Additives( JECFA) which was in safe range. Otherwise, the daily selenium intake through brick tea was 0. 188 µg, which contributed 0. 38% to the selenium recommended nutrient intake( RNI) by Chinese Nutrition Society. CONCLUSION: Excessive levels of lead in the brick tea is prominent. As, Hg and Se in brick tea are in low exposure level.

Establishment and evaluation of a method for determination of total arsenic in urine by test-tube rapid digestion hydride generation atomic fluorescence spectrometry / 中华地方病学杂志

Objective To establish and evaluate a method for determination of total arsenic in urine by test-tube rapid digestion hydride generation atomic fluorescence spectrometry.Methods After digestion of urine samples using graduated test-tube and graphite digestion apparatus,arsenic content in urine was determined with atomic fluorescence spectrometer.Then the test results were evaluated by using quality control measures,such as precision and accuracy experiments,and the results between different laboratories were reviewed and compared.Results The urinary arsenic was in a linear range of 0-0.300 mg/L,correlation coefficient (r) ＞ 0.999 3,detection limit was 0.000 21 mg/L,relative standard deviation (RSD) ≤4.62％ and the recoveries of standard addition were 93.9％-104.3％.The value of standard reference material measured was within the allowable range.The blind sample of the national urinary arsenic was qualified.Conclusions This method is suitable for large scale determination of urinary arsenic for its micro sample amount needed,less interference and strong practicability.The error results are in a controlled range.

The hydride generation atomic fluorescence spectrophotometry method for determination of urinary arsenic / 中华地方病学杂志

Objective To apply hydride generation atomic fluorescence spectrophotometry (HG-AFS method) in urinary arsenic detection,and to provide a better,newer and more convenient detection method for quantitative analysis of urinary arsenic.Methods According to the Guide to Develop Biological Sample Inspection Method(WS/T 68-1996) and Guide for Establishing Occupational Health Standards-part 5:Determination Methods in Biological Materials (GB/T 210.5-2008),HG-AFS method was established to detect arsenic content in urine after modification of the method for sample pretreatment,and to verify the linear range of standard curve and linearity,detection limit,precision,accuracy,stability of the sample,and to compare the experimental results of HG-AFS method with those of standard methods of WS/T 28-1996 and Determination of Arsenic in Urine by Cyanide Generation Atomic Fluorescence Method (WS/T 474-2015).Results The HG-AFS method linear range was from 0-100 μg/L,the correlation coefficient r =0.999 9,the detection limit was 0.07 μg/L,the precision was 1.96％-3.97％,and the recovery rate was 95.1％-105.0％.There was no statistical significance between HG-AFS method,the standard of WS/T 28-1996 or WS/T 474-2015 methods (t =1.539,0.353,all P ＞ 0.05).Conclusion The new method is superior to the current detection method owing to its low detection limit,high precision,good accuracy,and wide linear range.

A method for determination of arsenic in urine by hydride generation atomic fluorescence spectrometry using hydrogen peroxide as the main digestion reagent to digest urine / 中华地方病学杂志

Objective To establish a method for determination of arsenic in urine,using hydrogen peroxide as the main digestion reagent to digest urine,and using hydride generation atomic fluorescence spectrometry (HG-AFS) to determine arsenic (this method was referred to below),the feasibility of the application in the monitoring of endemic arsenic poisoning was discussed.Methods Temperature control instrument (60 holes) and supporting special calibration tube were used to digest urine.Digestion reagents was mainly hydrogen peroxide plus a small amount of nitric acid and sulfuric acid,HG-AFS was used to determinate.Based on standard curve to calculate linear relationship.Using this method to determinate detection limit,precision,accuracy and stability of samples,this method was compared with the national hygienic standard method (DDCAg method,WS/T 28-1996).Results The detection limit was 0.8 μg/L (1 ml of urine was tested),the correlation coefficient was larger than 0.999 5.Precision:3 samples were determined,the arsenic contents were (11.0 ± 0.6),(39.2 ± 1.0),(174.4 ± 3.8) μg/L and the relative standard deviations were 5.03％,2.59％ and 2.17％,respectively.Recovery rate:3 samples were determined for standard addition recovery test,the average recovery rate was 99.4％ and the recovery rate ranged between 94.0％-104.3％.Methods contrast:this method [(125.9 ± 61.6) μg/L] and DDCAg method [(121.3 ± 52.5) μg/L] were used to determinate 20 samples from endemic arsenic poisoning areas,respectively,the determination results of the two methods were not significantly different (t =1.22,P ＞ 0.05).Conclusions This method is built successfully,it has good precision and accuracy,it needs small amount of sample and reagent,the amount of harmful gases generated is greatly reduced,and it is easy to operate and beneficial to operator's health.Therefore,it is a good method to determine arsenic in urine,and it can be applied in prevention of endemic arsenism.

Determination of arsenic speciation in sulfidic waters by Ion Chromatography Hydride-Generation Atomic Fluorescence Spectrometry (IC-HG-AFS).

A method for the analysis of arsenic species in aqueous sulfide samples is presented. The method uses an ion chromatography system connected with a Hydride-Generation Atomic Fluorescence Spectrometer (IC-HG-AFS). With this method inorganic As(III) and As(V) species in water samples can be analyzed, including arsenite (HnAs(III)O3(n-3)), thioarsenite (HnAs(III)S3(n-3)), arsenate (HnAs(V)O4(n-3)), monothioarsenate (HnAs(V)SO3(n-3)), dithioarsenate (HnAs(V)S2O2(n-3)), trithioarsenate (HnAs(V)S3O(n-3)) and tetrathioarsenate (HnAs(V)S4(n-3)). The peak identification and retention times were determined based on standard analysis of the various arsenic compounds. The analytical detection limit was ~1-3 µg L(-1) (LOD), depending on the quality of the baseline. This low detection limit makes this method also applicable to discriminate between waters meeting the drinking water standard of max. 10 µg L(-1) As, and waters that do not meet this standard. The new method was successfully applied for on-site determination of arsenic species in natural sulfidic waters, in which seven species were unambiguously identified.

Quantitative Determination of Selenium Species in Se-enriched Yeast Using Liquid Chromatography-Hydride Generation Atomic Fluorescence Spectrometry / 分析化学

A rapid and sensitive method has been developed for the simultaneous determination of four selenium species Se(Ⅵ), Se(Ⅵ), selenomethionine, and Se-methylselenocysteine in Se-enriched yeast by liquid chromatography-hydride generation atomic fluorescence spectrometry (HPLC-HG-AFS). The isolation of the analytes from yeast samples was accomplished by proteaseⅩⅣ and trypsin enzymatic digestion. The target compounds were separated on a PRP-X100 anion exchange column and analyzed by HG-AFS. The mobile phase was 20 mmol/L (NH4)2HPO4. Good linearity was obtained for all the selenium species, with linear correlation coefficients higher than 0. 9996. The LODs of the four species were between 0. 5 and 5. 0 μg/kg. Average recoveries for the four analytes were in the ranges of 82 . 5%-101 . 2%, with intra-and inter-day RSD lower than 8. 6% and 14. 5, respectively. The proposed analytical method is simple, sensitive, with low operation cost, making it applicable for the determination of the selenium species in Se-enriched feeds.

Mercury Speciation Determination in Fish and Soil Samples Based on Low Pressure LC-AFS Combined with Rapid Sample Pretreatment / 分析化学

The build-in low-pressure monolithic column combined with hydride generation atomic fluorescence spectrometry ( HG-AFS ) was employed for speciation analysis of fish meat. The sample pretreatment and separation approach could be accomplished within 30 min. The proper amount of fish sample was weighed and smashed into puree. The extraction solution composed of 10% HCl, 1% thiourea, and 0. 15% KCl was added before loaded into the automatic temperature controlled vertex system with 2000 r/min. The sample solution was separated through Merck monolithic column, with 3% ( V/V) acetonitrile, 30 mmol/L amonium acetate and 0. 03%(V/V) 2-mercaptoethanol (2-ME) as the eluent. The after-column eluent was digested by novel UV digestion device with pipeline sintered into the lamp, and then detected by hydrid-generation AFS. The rapid LC separation enabled fast mercury speciation of fish sample within 10 min. The different UV lamp digestion effects, eluent components, carrier gas, shield gas, lamp current, as well as PMT working power was optimized. Under the optimal conditions, the robust system achieved detection limits (DL) of 0. 15 μg/L and 0. 14 μg/L for methylmercury and HgⅡ, respectively. The RSD (n=7) was less than 5%, the linear correlation coefficient was 0 . 999 , and the matrix spiked recovery was in the range of 85%-110% for Hg speciation. This method was used for the determination of Hg speciation in fish and soil samples, and was proofed to be a reliable, easy approach for daily inspection.