Determination of total arsenic in soft drinks by hydride generation atomic fluorescence spectrometry

A highly sensitive and simple method has been developed for the determination of total arsenic, by continuous hydride generation and atomic fluorescence spectrometry (HGAFS), in refreshing drink samples as colas, teas and fruit juices. Samples were mixed with concentrated HCl and KI to obtain final concentrations of 2 mol l⁻¹ and 1%, respectively. These solutions were aspirated and merged with a reducing NaBH₄ 3% (m/v) solution, with sample and NaBH₄ flow rates of 12.5 and 1.5 ml min⁻¹, respectively. The hydride generated in a 170 cm reaction coil was transported to the detector with an Ar flow of 400 ml min⁻¹. The recovery values of added concentrations, from 0.1 to 0.9 ng ml⁻¹, of arsenic in colas, teas and fruit juices were 94 ± 5, 101 ± 9 and 94 ± 6, respectively, achieving variation coefficients between 0.1% and 9%, confirming the accuracy of developed procedure. Detection limit, ranged from 0.01 to 0.03 ng ml⁻¹. On comparing the direct determination with a reference procedure made after dry ashing operation it can be noticed that the direct approach provides a simplification of the handling and time consuming, achieving statistically comparative results.     

Comparison of graphite furnace and hydride generation atomic absorption spectrometry for the determination of selenium status in chicken meat

Four different procedures for the determination of selenium in chicken meat by atomic absorption spectrometry were investigated. They consisted on conventional ambient pressure acid digestion carried out before and after sample drying, associated or not with fat extraction. For all procedures muscle and skin were analyzed separately. Drying was carried out in a conventional oven at 65 °C for 24 h. For fat extraction different solvents and solvent mixtures were investigated considering both extraction yield and sample adequacy for further AAS measurement. Acid digestions were carried out with mixtures of HNO₃ and HClO₄. After digestion, selenium was measured either by Hydride Generation (HGAAS) or by Graphite Furnace Atomic Absorption Spectrometry (GFAAS). For the reduction of Se(VI) prior to the HGAAS determination, 8% (w/v) NaBr, 6 mol/l HCl (both with and without sulfamic acid), as well as UV radiation were investigated. Tests with spiked samples have shown that either UV radiation (pH 8) or NaBr/sulfamic acid presented good recoveries. In this way the HGAAS determination of selenium in tissue was carried out without interference whereas for the fatty fraction the results were satisfactory only if GFAAS was used. The results showed that drying the sample and extracting the fat prior to digestion is advantageous once the amount of acid necessary can be significantly reduced. The precision, expressed as relative standard deviation, was about 6.5% and 0.8% for GFAAS and HGAAS measurements, respectively. The limits of detection for HGAAS and GFAAS, based on three times the standard deviation of the blanks were 1 μg/l and 0.6 μg/l, respectively. The results have shown that in chicken meat 59% of the selenium is found in the muscle tissue while the skin responds for 41%.     

原子荧光光谱法测定水中痕量砷的优化研究

目的 建立一种原子荧光光度法测定水中痕量砷的方法.方法 应用AFS-2202E双通道原子荧光光度计测定痕量砷,对仪器的工作参数(包括负高压、载气流量和灯电流等)及样品的化学条件作了研究及优化.通过变量找到氢化物发生原子荧光法测定水中痕量砷的最佳工作条件.结果 硼氢化钾浓度为20～24 g/L之间、灯电流在55～60 m...     

氢化物发生原子荧光光谱法和电感耦合等离子体质谱法测定茶饮料中总砷的比较研究

利用氢化物发生原子荧光光谱法(atomic fluorescence spectrometry,AFS)和电感耦合等离子体质谱法(inductively coupled plasma mass spectrometry,ICP-MS)来测定茶饮料中的总砷含量。通过比较可知:AFS法检测耗时少、灵敏度好;ICP-MS法检测限小、可同时检测多种元素;两者都能满足茶饮料中总砷的检测,由于AFS法耗时短、运行成本低,更适合茶饮料中总砷的测定。此外,所检茶饮料的总砷含量低于国标限量,且茶饮料中总砷含量与茶的种类有着密切的关系。     

微波消解-氢化物原子荧光光谱法测定大米中的总砷

针对《食品中总砷及无机砷的测定》GB 5009.11-2014对食品中总砷的测定方法进行了改进.根据国家标准GB 5009.11 2014总砷的测定中氢化物原子荧光光谱法,分别采用微波消解与湿法消解对质控样品和试样样品处理后进行总砷含量的测定.结果 表明:总砷在0～10.0 μg/L线性范围的相关系数为0.999 8,...     

Non-chromatographic speciation of inorganic arsenic in mushrooms by hydride generation atomic fluorescence spectrometry

A non-chromatographic speciation method has been developed for the determination of inorganic arsenic in cultivated and wild mushroom samples from different origins. The ultrasound-assisted extraction of the toxic arsenic species As (III) and As (V) was performed for 10 min with 1 mol l⁻¹ H₃PO₄ and 0.1% (m/v) Triton X-100. After phase separation the residue was washed with 0.1% (w/v) EDTA and centrifuged. As (III) and As (V) were determined by hydride generation atomic fluorescence spectrometry. Speciation was made using proportional equations corresponding to two different measurement conditions, (i) directly feeding sample extracts diluted with HCl and (ii) after reduction with KI and ascorbic acid for 30 min. The limits of detection of the method were 6.3 and 5.0 ng g⁻¹ for As (III) and As (V), respectively. Recovery percentages varied between 91% and 108% for As (III) and from 90% to 109% for As (V) indicating that As species interconversion was avoided. As (III) concentrations from 264 to 81 μg g⁻¹ and As (V) concentrations from 246 to 59 μg g⁻¹ were found in Spanish cultivated mushrooms. For Chinese wild mushrooms As (III) varied between 624 and 117 μg g⁻¹ and As (V) from 380 to less than 5 μg g⁻¹. The accuracy of the method was checked by the determination of total As (from the sum of As (III) and As (V)) in a tomato leaves reference sample, with good agreement with the certified value.     

氢化物发生原子荧光法测定大豆卵磷脂中的砷

采用氢化物发生原子荧光法测定大豆卵磷脂中的砷,确定了仪器的最佳条件,探讨了还原剂溶液浓度介质酸浓度,预还原剂,载气流量等对测定砷的影响.在选定的操作条件下,砷的最低检出限为0.29 ng/mL,相对标准偏差为2.3%.用建立的方法测定大豆卵磷脂中的砷,操作简单、快速、灵敏度高.     

氢化物发生-原子荧光法测定食用醋中的As

为准确测定食用醋中As的含量,采用了氢化物发生原子荧光法测定方法。通过实验确定了仪器的灯电流40mA、负高压315V和还原剂KBH4浓度0．12％为最佳条件。在此条件下,As的最低检出限为0．08μg／L,相对偏差为1．8％,线形范围1．0μg／L～200μg／L。用该法测其结果符合国家食品卫生标准。     

Determination of arsenic in chicken feed by hydride generation atomic absorption spectrometry after pre-concentration with polyurethane foam

A pre-concentration procedure with solid-phase extraction was developed for the determination of arsenic (As) in chicken feed using hydride generation atomic absorption spectrometry (HG-AAS). The procedure was based on the sorption of As(III) ions as complexes with ammonium pyrrolidine dithiocarbamate onto a mini-column packed with polyurethane foam. After pre-concentration, the As was removed from the mini-column by acid solution, and the analyte content in the eluate was measured by HG-AAS. The following main experimental conditions were established: adjustment of the As solution pH with 0.05?mol?l^?1 HCl, 2.88?×?10^?3?mol?l^?1 complexing agent concentration and 6.0?mol?l^?1 eluting hydrochloric acid concentration. The proposed method produced an enrichment factor of 67, with 0.050 and 0.165?µg?g^?1 limits of detection and quantification, respectively. The procedure was applied to the determination of As content in two types of chicken feed using the proposed procedure and atomic absorption spectrometry with electrothermal atomisation (ETAAS). The t-test indicated that the results were not significantly different at a confidence level of 95%.     

氢化物原子荧光光度法测定无机砷方法的探讨

通过对氢化物原子荧光光度法测定食品中无机砷含量的整个测定过程进行研究,系统分析了该方法中标准溶液系列随着存放时间的长短其荧光强度的变化。结果显示,无机砷浓度在0-30．Oμg／L,冰箱里0-4℃存放1个月,能有效控制测定结果的准确性,确保检验工作的质量。     

Simultaneous multi-channel hydride generation atomic fluorescence spectrometry determination of arsenic,bismuth, tellurium and selenium in tea leaves

A novel, rapid and sensitive method for the simultaneous multi-channel hydride generation atomic fluorescence spectrometry (HG-AFS) determination of total arsenic (As), total bismuth (Bi), total tellurium (Te) and total selenium (Se) in tea leaves was proposed. The operating parameters of self-made multi-channel HG-AFS were optimised, including negative high voltage of photo multiplier tube (PMT), the flow rates of carrier and shield gas, observation height and lamp currents. The conditions of hydride generation for As, Bi, Te and Se were studied in details. Under optimal conditions, the method detection limits (MDL) for As, Bi, Te and Se in tea leaves were 0.0152 μg g⁻¹, 0.0080 μg g⁻¹, 0.0022 μg g⁻¹ and 0.0068 μg g⁻¹, respectively. The proposed method was successfully applied to the simultaneous determination of As, Bi, Te and Se in various tea leaves and the spike recoveries were in the range of 90–103%. The accuracy of method was validated by analysing a tea certified reference material. The obtained values were consistent with the certified ones.     

Study of a microwave digestion method for total arsenic determination in marine mussels by electrothermal atomic absorption spectrometry: application to samples from the Ria de Arousa

Arsenic determination in mussel tissue was performed by electrothermal atomic absorption spectrometry (ETAAS) with Zeeman background correction and using iridium as a chemical modifier. Samples were digested by microwave heating using a mixture of nitric and sulphuric acids. This mixture makes possible the destruction of organoarsenic compounds, specifically arsenobetaine, prior to the graphite furnace determination. Optimum pyrolysis and atomization temperatures were 1,100 and 1,800 °C, respectively. The method was precise (with RSD% < 10), accurate (study of a certified reference material: 18.4 ± 1.4 μg As g⁻¹ vs. a certified content: 18.0 ± 1.1 μg As g⁻¹; recoveries between 90 and 104%) and sensitive (LOD 0.21 μg g⁻¹ on a dry weight basis). The method was applied to the determination of arsenic in aquaculture mussels collected in four sampling campaigns from the productive Ría de Arousa (estuary sited in Galicia, NW of Spain).     

Determination of arsenic and mercury in sunflower oil by electrothermal atomic absorption

A simple and fast method for the determination of arsenic (As) in sunflower oil by electrothermal atomic absorption (ETAAS) is described. The optimal instrumental parameters for ETAAS measurement of As species in stable and homogeneous soap emulsions prepared from oil samples with tetramethylammonium hydroxide (TMAH) have been established. The limit of determination is 5 ng g^-1 total As in sunflower oil. A second approach involving extraction of As and mercury from sunflower oil and consequent ETAAS measurement is also described. Simultaneous quantitative extraction of As(III), As(V), monomethylarsonate (MMA) and dimethylarsinate (DMA) as well as Hg(II), monomethylmercury(II)chloride (MMC), dimethylmercury (DMM), diethylmercury (DEM) and diphenylmercury (DPM) is achieved by using an extraction mixture comprising of 0.1^M NH₃/0.01^M EDTA. Pre-reduced palladium is applied as an effective modifier for the next ETAAS measurement of all extracted species. The method of standard addition is employed for calibration. The accuracy and reproducibly of the methods was established by spike and recovery experiments and parallel analysis of sunflower oils from the marketplace. Limits of determination of 2 ng g^-1 for As and 3 ng g^-1 for mercury were obtained.     

微波消解-石墨炉原子吸收光谱法测定花生中镉含量

本文研究了高脂肪高蛋白材料花生中镉含量测定方法。采用微波消解法处理花生样品,使用石墨炉原子吸收光谱法测定花生中镉含量。从广东、湖北和辽宁3省随机抽取收获的9个花生样品进行检测,镉含量范围为0．061～0．529mg／kg,RSD为1．22％-8．75％（n=6,c=0．859—7．409ng／mL）,该方法检出限为0．00019mg／kg,加标回收率为95．4％～100．1％,具有灵敏、快速、准确的特点,可用于高脂肪高蛋白样品中镉含量的测定。     

预富集-氢化物发生原子吸收光谱法测定水产品中的痕量硒

研究了预富集-氢化物发生原子吸收光谱法测定水产品中的痕量硒的新方法。用吡咯烷二硫代氨基甲酸铵(APDC)作配位剂,在pH4.0～6.5的条件下,用固体硅胶捕集、膜滤纸抽滤分离Se-APDC配合物,然后用0.1moL/L盐酸从膜滤纸上洗下硅胶,得到能够直接用氢化物原子吸收光谱法测定的硒悬浊液。该法操作简便,富集速度快。100mL溶液,特征质量为1.5×10-11g/1%。在最佳条件下,用这个方法测定了水产品中的痕量硒,当n=6时,标准偏差为0.0027～0.0054,变异系数为0.012～0.028,样品的加标回收率在95.2%～104.6%之间,结果较为满意。     

顺序注射氢化物发生-原子荧光光谱法同时测定大蒜中的硒和砷

建立了一种顺序注射氢化物发生-原子荧光光谱法测定大蒜中Se和As含量的方法,同时讨论了共存离子的干扰情况。在最佳实验条件下,Se和As的检出限分别为0.13μg/L和0.090μg/L,加标回收率为93.6%～103.8%。     

原子吸收分光光度法测定接装纸中的砷、铅

建立了用氢化物发生器-、石墨炉-原子吸收分光光度法测定接装纸中砷、铅含量的方法。结果表明:①铅测定最佳条件为样品中硝酸浓度1.0%(体积分数),添加基体改进剂;②砷测定最佳条件为样品中硝酸浓度0.05mol/L,硼氢化钠浓度2.0%(质量分数),载液中盐酸浓度5.0%(体积分数);③砷、铅的相对标准偏差≤6.65%,回收率在96.0%~103.0%之间。     

氢化物发生-原子荧光光谱法测定食品中的微量砷

砷是目前公认的对人体有害的元素,采用氢化物发生-原子荧光光谱法测定食品中微量砷的含量。研究了硼氢化钾浓度、酸介质及其酸度、共存离子等因素对砷测定的影响,优化了仪器工作条件。方法回收率在94.0%～104.0%,检出限为0.18ng/mL。     

Determination of inorganic arsenic species (As and As) in muscle tissues of fish species by electrothermal atomic absorption spectrometry (ETAAS)

Arsenic speciation was carried out in muscle tissues of freshwater fish species. Inorganic arsenic species (As³⁺and As⁵⁺) were extracted with chloroform, prior to microwave assisted digestion with concentrated HClO₄ and Fe₂(SO₄)₃. The extracted As³⁺ and As⁵⁺ were determined by electrothermal atomic absorption spectrometry (ETAAS). The accuracy of the technique was evaluated by using certified reference material DORM-2. The limit of detection of the method was 0.004 and 0.005 μg/g for As³⁺ and As⁵⁺, respectively. The mean relative standard deviation values (RSD) in real sample analysis were 1.90 and 3.92 for As³⁺ and As⁵⁺, respectively. The results demonstrated the suitability of the procedure for screening and quantification of As species in biological samples. The mean concentration of As³⁺ and As⁵⁺ in muscle tissues of studied fish species ranged from 1.19 to 2.05 and 0.17 to 0.46 μg/g, respectively. The contribution of the daily intake of inorganic As, based on the consumption of 250 g fresh fish muscles/body weight/day was found in the range of 1.21–1.91 μg/kg/day.     

Determination of arsenic in foods by flow injection on-line sorption pre-concentration with hydride generation atomic fluorescence spectrometry

A method was developed for the determination of total arsenic in foods using flow injection on-line sorption coupled with hydride generation atomic fluorescence spectrometry (HG-AFS) using a cigarette filter as the sorbent material. After reducing As(V) to As(III) by using L-cysteine, the determination of total arsenic was achieved through on-line formation and retention of the pyrrolidine dithiocarbamate arsenic complex (As(III)–PDC) on the cigarette filter, which was packed in the pre-concentration column and total arsenic was determined by HG-AFS. The analytes were eluted with 1.68 mol l^?1 HCl from the sorbent material. With consumption of 22 ml of the sample solution, an enrichment factor of 25.6 was obtained at a sample throughput of 11.6 h^?1. The detection limits (3 standard deviations) and the precision (relative standard deviation) in foods ranged from 2.5 to 9.9 ng g^?1 and from 1.1 to 2.2%, respectively. The method was used to determine arsenic in carrot, mushroom, chicken tissue, cod fish, rice, common carp and shrimp.