毛细管电泳-电感耦合等离子体质谱(CE-ICP-MS)联用测定干海产品中的六种砷形态化合物

采用电感耦合等离子体质谱(ICP-MS)测定了鱿鱼、银鱼、沙丁鱼、虾、牡蛎、蛤蜊、紫菜、羊栖菜、海带、浒苔10种干海产品中的砷总量,建立了毛细管电泳(CE)与ICP-MS联用测定亚砷酸盐As(III)、砷酸盐As(V)、甲基砷酸(MMA)、二甲基砷酸(DMA)、砷甜菜碱(AsB)和砷胆碱(AsC)六种砷形态化合物的分析方法。结果发现除了浒苔其余干海产品中砷总量均超出了无机砷允许限值(GB 2762-2005),形态分析结果表明干海产品中主要是有机砷,萃取液中无机砷含量仅占砷总量的0~15.2%。该方法简单方便、快速,样品消耗量少,而且具有较好的准确性,适用于其他生物样品中砷形态化合物的分析。     

食品中砷的形态分析研究进展

砷是一种公认的有毒有害物质,现在相关研究中常涉及的砷形态包括亚砷酸盐(arsenite,AsⅢ)、砷酸盐(arsenate,AsⅤ)、一甲基砷酸(monomethyl arsenic acid,MMAⅤ)、二甲基砷酸(dimethyl arsinic acid,DMAⅤ)、砷甜菜碱(arsenobetaine,AsB)以及砷胆碱(arsenocholine,AsC)。砷的形态与其生物可给性、毒性密切相关,烹调过程能够影响食品中砷的形态,进而可能影响到砷对人体健康的风险性。因此,建立食品中砷形态分析的检测方法具有十分重要的意义。本文对砷的形态分析的检测方法及研究现状进行了综述,重点介绍了溶剂提取及微波、超声辅助提取等前处理方法以及砷的形态分析方法在食品中的应用,同时对砷的形态在烹调过程中的变化进行了阐述,并对未来发展方向进行了展望。     

HPLC联用ICP-MS法测定水产品中常见的6种砷形态

建立高效液相色谱联用ICP-MS同时测定水产品中的三价砷(砷III)、五价砷(砷V)、一甲基砷(MMA)、二甲基砷(DMA)、砷胆碱(As C)和砷甜菜碱(As B)的方法。样品经水与甲醇体系超声提取,阴离子交换柱分离,ICP-MS定量分析。结果表明,常见的6种砷形态浓度在0.1~100μg/L范围内线性关系良好,线性相关系数均大于0.995;方法检出限为0.5~1.25μg/kg;方法加标回收率在80%~110%之间;以重复性考察方法重现性,RSD(n=6)在5.0%以内,以精密度考察方法稳定性,RSD(n=6)在5.0%以内。试验证明该方法具有操作简单、灵敏度高、检测结果准确可靠等优点,可以用于水产品中6种砷形态的检测。     

高效液相色谱-氢化物发生原子荧光联用法检测 不同基质食品中的砷含量及其形态

目的建立高效液相色谱-氢化物发生原子荧光联用法检测大虾、金枪鱼、虾油、大米和菠菜等不同基质食品中的砷含量及其化学形态。方法将大虾、金枪鱼、虾油、大米和菠菜样品采用HNO_3(0.15 mol/L)浸提,高效液相色谱-氢化物发生原子荧光联用法进行砷形态的研究,并用湿法消解-原子荧光光谱法进行总砷含量的测定。结果所测大虾、金枪鱼、虾油、大米、菠菜样品总砷含量为0.23~4.68 mg/kg,有机砷含量为0~3.9 mg/kg。海产品中主要砷形态为2种砷化物:二甲基砷(DMA)和砷甜菜碱(AsB);大米及菠菜样品中主要的砷形态为:三价砷As(Ⅲ)、二甲基砷(DMA)和五价砷As(Ⅴ)。结论该方法操作简单,灵敏度高,重现性好,适用于食品中砷形态含量的定量检测。     

液相色谱-电感耦合等离子体-质谱法分析海藻碘浓缩液中砷形态

目的 建立液相色谱-电感耦合等离子体质谱法(liquid chromatography-inductively coupled plasma mass spectrometry, LC-ICP-MS)测定海藻碘浓缩液中6种不同形态砷化合物的分析方法。方法 单因素实验确定对不同形态砷化合物LC-ICP-MS的分离条件, 包括流动相浓度、pH及洗脱方式。以总砷提取效率的高低评价三种不同的提取砷化合物的方法, 确定最佳方法。结果 以稀硝酸浸提的前处理方法的提取效果最佳, 提取效率为84.28%~92.99%;以25 mmol/L pH8.0磷酸二氢铵溶液和水作为流动相, 采用梯度洗脱的方式, 可以将6种砷形态完全分离,结果显示6种海藻碘样品中砷甜菜碱AsB含量较多, 而亚砷酸盐As(III)、砷酸盐As(V)和二甲基砷酸DMA含量较少, 未检测出砷胆碱AsC和一甲基砷酸MMA, 样品有毒砷含量占浓缩液总砷含量的2.01%~3.69%, 本方法加标回收率在80.4%~101.5%之间。结论 海藻碘浓缩液中砷形态的主要存在形式为AsB,本方法准确、简单,适合海藻碘浓缩液中砷形态分析。     

HPLC-ICP-MS法测定香菇及培养料中不同形态砷的含量

采用高效液相色谱(HPLC)和电感耦合等离子体质谱(ICP-MS)联用测定香菇及香菇培养料中亚砷酸盐As(Ⅲ)、砷酸盐As(Ⅴ)、一甲基砷酸盐(MMA)、二甲基砷酸盐(DMA)和砷甜菜碱(As B)等5种砷元素化合物。样品经70℃超声萃取,阴离子色谱柱分离,ICP-MS检测,5种不同形态的砷分离效果良好,线性范围0~100.0 ng/m L,相关系数在0.9999以上,加标回收率81.0%~108.9%之间,相对偏差1.6%~6.3%(n=6)。用实际样品检测,培养料中的砷元素主要以As(V)的形式存在,其含量与栽培时间关系不大。鲜香菇和干香菇中则含有较多的As(Ⅲ)、As(Ⅴ)和As B,虽然总砷结果符合国标限量要求,但高毒的无机砷占大多数。     

LC-ICP-MS法研究莲藕中砷的形态分布

本文通过测定莲藕不同砷浓度环境、不同生长阶段和不同器官中总砷及砷的5种形态(亚砷酸盐As(Ⅲ)、砷酸盐As(Ⅴ)、一甲基砷MMA、二甲基砷DMA和砷甜菜碱As B)的含量,研究了莲藕中砷的形态分布规律。采用优化的超声酸提取方法,用1%HNO3在70℃超声提取40 min,25 mmol/L磷酸二氢铵溶液(pH 8.0)为流动相等度洗脱,液相色谱-电感耦合等离子体质谱联用(LC-ICP-MS)法进行测定,各形态提取完全、稳定,8 min内基线分离。高砷环境栽培莲藕的无机砷比率略高于低砷环境的。莲藕在旺盛生长期对砷的富集能力高于结藕期,除藕外,地下部分总砷含量和无机砷比率普遍高于地上部分。结藕期无机砷比率降低,有机砷以As B、MMA和少量DMA形式存在。各器官中无机砷含量比例为29.03%~45.21%不等,可食部分藕和莲蓬中无机砷含量比例最低,有利于食品安全控制。     

深圳市盐田区海产品总砷及砷形态调查研究及风险评价

采用电感耦合等离子体质谱法(ICP/MS)检测海产品的总砷含量,液相色谱-电感耦合等离子体质谱联用(HPLC-ICP-MS)检测海产品5种砷形态含量。在被检测的180份海产品中,168份海产品的总砷含量高于0.5mg/kg,所占比例为93.3%,均值为9.43mg/kg。该168份海产品的砷形态(As B、AsⅢ、AsⅤ、MMA、DMA)检测结果为无机砷(AsⅢ与AsⅤ)含量均低于定量限0.06mg/kg;检出含量高于0.5mg/kg的砷甜菜碱(As B)124份(73.8%),均值为7.05mg/kg;二甲基砷(DMA)49份(29.2%),均值为0.25mg/kg;一甲基砷(MMA)未检出。结果显示,无毒的As B含量明显高于低毒的DMA(P0.05),含量高于0.5mg/kg的As B检出比例也明显高于DMA(P0.05),表明本地区海产品安全风险较低,食用安全性有保障。     

广州市售海产品中砷质量安全与健康风险评估

目的对广州市售海产品进行砷质量安全评价与健康风险评估。方法采用等离子体质谱仪和高效液相色谱-原子荧光联用仪分别对广州10种市售海产品中总砷和5种砷形态化合物:亚砷酸(arsenictrioxide,As(III))、砷酸(arsenicacid,As(V))、一甲基砷(monomethylarsenic,MMA)、二甲基砷(dimethylarsenic,DMA)和砷甜菜碱(arsenobetaine, AsB)的含量进行测量,根据GB 2762-2017《食品安全国家标准食品中污染物限量》海产品中砷含量的要求对海产品质量安全进行评价,利用危险熵数(hazardquotient,HQ)和致癌风险概率(carcinogenicrisk,CR)对其进行健康风险评估。结果海产品中总砷含量为1.45～42.54mg/kg,所有海产品中均能检测到5种砷化合物,其中无毒的AsB比例最高(93.45～99.96%)。在所有海产品中,贝类总砷含量最高,无毒的AsB所占比例较高;鱼类总砷含量低于贝类, AsB含量和比例较高,无机砷含量和比例较低。海产品中无机砷的含量均低于限量值,在国标要求的允许摄入范围内。海产品中无机砷的HQ均1, CR1×10~(-4)。结论广州市售海产品中砷含量处于安全水平,日常消费对人类不会造成致癌风险以及健康威胁。     

不同工艺的树苔提取物中As的总量和形态

为了解不同工艺对树苔提取物中As的影响,采用ICP-MS、RP-HPLC-ICP-MS技术对不同提取、分离工艺制得的树苔提取物中As的总量和形态分布进行了分析。结果表明:1常规的乙醇复提、冷冻分离等操作,可以将树苔提取物中的As总量降低37%~49%;2不同溶剂提取的树苔提取物中,均未检测出砷胆碱(As C);乙醇、乙醇-丙二醇和亚临界丁烷提取物中主要为As(III)和二甲基砷酸(DMA),水提取物中主要为As(V)和DMA;3乙醇和乙醇-丙二醇提取物在经过乙醇复提和/或冷冻分离等操作后,各种形态As的相对比例没有发生较大变化,只是As总量有所减少。水提取的树苔提取物在进行乙醇复提和冷冻分离后,As(V)减少的量大于As(III)和DMA,表明As(III)和DMA在乙醇中的溶解度大于As(V)。     

Determination of 6 arsenic species present in seaweed by solvent extraction,clean-up,and LC-ICP/MS

The analytical method was developed for the speciation of 6 arsenic species [As(III), As(V), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), arsenobetaine (AsB), and arsenocholine (AsC)] in sea mustard (Undaria pinnatifida), dashima (Laminaria japonica), and laver (Porphyra tenera) of seaweed. After extraction under sonication with a solution of 50%(v/v) methanol in 1% HNO₃ and subsequent clean-up with anion-exchange cartridge, arsenic species were quantified by liquid chromatography with inductively coupled plasma-mass spectrometry. The ion-exchange cartridge is effective to remove a lot of interference. The gradient elution method was used for high resolution of arsenic species and the optimum pH of mobile phase is 6.0 and 6.2. Limit of detection and quantification were set at 0.06–0.12 and 0.20–0.40 ng/mL, respectively. Overall recoveries of arsenic species from fortified samples in seaweed were 81.1–118.8%, except for AsB and AsC in dashima and laver. This proposed method could be useful for quantification and speciation of arsenic species in seaweed as well as other foodstuffs.     

Arsenic species in rice and rice-based products consumed by toddlers in Switzerland

Inorganic arsenic (iAs) is a contaminant present in food, especially in rice and rice-based products. Toxicity of arsenic compounds (As) depends on species and oxidative state. iAs species, such as arsenite (As(III)) and arsenate (As(V)), are more bioactive and toxic than organic arsenic species, like methylarsonic acid (MMA(V)) and dimethylarsinic acid (DMA(V)) or arsenosugars and arsenobetaine. An ion chromatography-inductively coupled-plasma-mass spectroscopy method was developed to separate the four following arsenic anions: As(III), As(V), MMA(V) and DMA(V). Sample preparation was done in mild acidic conditions to ensure species preservation. The predominant arsenic species found in rice and rice-based products, except for rice drinks, was As(III), with 60–80% of the total As content, followed by DMA(V) and As(V). MMA(V) was measured only at low levels (<3%). Analyses of rice products (N = 105) intended for toddlers, including special products destined for infants and toddlers, such as dry form baby foods (N = 12) or ready-to-use form (N = 9), were done. It was found in this study that there is little or no margin of exposure. Risk assessment, using the occurrence data and indicated intake scenarios compared to reference BMDLs as established by EFSA, demonstrated toddlers with a high consumption of rice based cereals and rice drinks are at risk of high iAs exposure, for which a potential health risk cannot be excluded.     

Quantification of four arsenic species in fruit juices by ion-chromatography-inductively coupled plasma-mass spectrometry

A method using ion chromatography-inductively coupled plasma-mass spectrometry (IC-ICP-MS) for the quantification of arsenic species in fruit juices has been developed and validated. The method is capable of quantifying four anionic arsenic species - arsenite (As(III)), arsenate (As(V)), dimethylarsinic acid (DMA) and monomethylarsonic acid (MMA) - in the presence of unretained species such as arsenobetaine (AsB). Method validation was based on repeatability, analysis of reference materials, recovery of fortified samples, and determination of detection and quantification limits. The method was tested for use with apple, pear, cranberry, grape (red, white and purple) juices, as well as several juice blends. Limits of detection were 0.35, 0.41, 0.45 and 0.70?μg?kg(-1) for As(III), DMA, MMA and As(V), respectively. Chromatographic recovery was good for most samples (90-107% compared to total arsenic), though recovery for some grape juice samples was lower (67-78%).     

Quantification of four arsenic species in fruit juices by ion-chromatography–inductively coupled plasma–mass spectrometry

A method using ion chromatography–inductively coupled plasma–mass spectrometry (IC–ICP–MS) for the quantification of arsenic species in fruit juices has been developed and validated. The method is capable of quantifying four anionic arsenic species – arsenite (As(III)), arsenate (As(V)), dimethylarsinic acid (DMA) and monomethylarsonic acid (MMA) – in the presence of unretained species such as arsenobetaine (AsB). Method validation was based on repeatability, analysis of reference materials, recovery of fortified samples, and determination of detection and quantification limits. The method was tested for use with apple, pear, cranberry, grape (red, white and purple) juices, as well as several juice blends. Limits of detection were 0.35, 0.41, 0.45 and 0.70?µg?kg^?1 for As(III), DMA, MMA and As(V), respectively. Chromatographic recovery was good for most samples (90–107% compared to total arsenic), though recovery for some grape juice samples was lower (67–78%).     

Metabolism of arsenic by sheep chronically exposed to arsenosugars as a normal part of their diet. 1. Quantitative intake,uptake, and excretion

Information on the effects of long-term organoarsenical consumption by mammals is limited despite the fact that foodstuffs, especially seafood, often contain organoarsenicals at very high concentrations. Here we evaluate the intake, uptake, and excretion (urine and feces) of arsenic by sheep that live on North Ronaldsay in the Orkney Islands and naturally consume large amounts of arsenosugars through their major food source-seaweed. The sheep eat a broad variety of seaweed species, and arsenic concentrations were determined in all the species observed eaten by the sheep (5.7-74.0 mg kg(-1) dry mass). Because of preference and availability, they feed mostly on the seaweed species found to contain the highest arsenic concentrations: Laminaria digitata and Laminaria hyperborea (74 +/- 4 mg kg(-1) dry mass). To quantify the arsenic intake by the sheep, a feeding experiment reflecting natural conditions as close as possible was set up. In the feeding trial, the average daily intake of arsenic by 12 ewes was 35 +/- 6 mg (97% of water-extractable arsenic was present as arsenosugars) gained from feeding on the two brown algae. To test the possible influence of microflora on the metabolism of arsenosugars, six of the sheep were adapted to feeding on grass for 5 months before the start of the trial (control sheep), and the remaining six sheep were kept on their normal seaweed diet (wild sheep). No significant difference in seaweed/arsenic intake and arsenic excretion was found between the two groups of sheep. The arsenic excreted in the feces represents 13 +/- 10% (n = 12) of the total consumed, and on the assumption of that, the average urinary excretion is estimated to 86%.The main arsenic metabolite excreted in urine was dimethylarsinic acid (DMA(V)) (60 +/- 22%) and minor amounts of dimethylarsinoylethanol (DMAE), methylarsonic acid (MA(V)),tetramethylarsonium ion (TMA+), and arsenate (As(V)) together with seven unknown arsenic compounds were also excreted. The urinary arsenic excretion pattern showed a lag period (>4 h) before significant quantities appeared in the urine, an excretion rate that peaked between 4 and 28 h after seaweed intake and a relatively slow half-life (17 h) after end of intake.     

Sequential extraction combined with HPLC–ICP-MS for As speciation in dry seafood products

A sequential extraction procedure followed by HPLC–ICP-MS analysis was developed for the speciation and quantization of arsenic species in dry seafood products (DSPs). The extraction process involved three major steps, which produced respectively three As fractions: non-polar (As_nonpolar), polar (As_polar) and inorganic arsenic species (As_inorganic). The extraction efficiency (EE%) is in the range of 87–115%. As_nonpolar is 0.6–10.2% of total arsenic in DSPs, which is served as the index of level of arsenolipid. For As_polar and As_inorganic, a hyphenated HPLC–ICP-MS technique was established for the separation and quantification of six arsenic species including arsenobetaine (AsB), arsenocholine (AsC), arsenite (AsIII), arsenate (AsV), monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA). The results indicate that AsB and AsV are the two dominate species in DSPs, while all other species are present in relatively low concentrations. The recovery efficiency of 77–02.8% could be obtained with spike recovery test in this two-steps extraction.     

Modeling arsenic in the Patuxent Estuary

A water quality model was developed to track the fate and transport of four arsenic species in the Patuxent Estuary: arsenate (As(V)), arsenite (As(III)), methylarsonate (MMA), and dimethylarsinate (DMA). Processes simulated include mass transport, solid-liquid partitioning with suspended solids, uptake and transformation of As(V) by phytoplankton, oxidation of As(III), demethylation of MMA and DMA, and settling/deposition/ resuspension of particulate arsenic in the water column. A sediment module was also developed and linked with the water column to generate fluxes of inorganic arsenic from the sediment bed. The arsenic model was calibrated using water quality data from the Patuxent Estuary over a period ranging from May 24, 1995 to October 29, 1997. Model results indicated that transformation of arsenic by phytoplankton is not a significant source of DMA to the lower Patuxent. Instead, results suggested that the primary source of methylated arsenic (DMA and MMA) to the lower estuary is beyond the downstream boundary (Chesapeake Bay). However, model results supported the hypothesis that flux of arsenic from the sediment is a significant source of inorganic arsenic to the lower estuary.     

高效液相色谱氢化物发生原子荧光光谱联用检测海藻中砷形态

目的测定14种海藻样品中总砷和无机砷的含量,同时分析样品中6种砷形态。方法将海藻样品经过微波消解的前处理方法,通过电感耦合等离子体质谱(inductively coupled plasma mass spectrometry,ICP-MS)测定总砷含量;根据国标方法中无机砷检测的前处理方法,通过原子荧光光谱(atomic fluorescence spectrometry,AFS)测定无机砷含量;最后通过酸提的前处理方法,利用高效液相色谱-氢化物发生-原子荧光光谱法(high performance liquid chromatography-ultraviolet photo-oxidation-hydride generation-atomic fluorescence spectrometry,HPLC-(UV)-HG-AFS)测定海藻样品中6种形态砷含量并与国标无机砷方法比较。结果 14种海藻样品中总砷含量为0.038~46.2 mg/kg;无机砷含量为0.006~19.3 mg/kg;对HPLC-(UV)-HG-AFS仪器的优化和方法的摸索后,从海藻样品中主要测得的砷形态为As(III)、As(V)和DMA,MMA含量较少,没有测出As B和As C。结论在砷形态较为复杂的海藻样品检测中,通过HPLC-(UV)-HG-AFS检测方法可以有效避免无机砷前处理中可能出现的有机砷向无机砷转变的现象,降低干扰,增加测试的准确性,更为具体地表现海藻样品中主要的砷形态含量。