高效液相色谱-电感耦合等离子体质谱法测定 大米中无机砷

目的建立高效液相色谱-电感耦合等离子体质谱法测定大米中无机砷的分析方法。方法采用两种前处理方法对大米中的无机砷进行提取,经高效液相色谱分离后,利用电感耦合等离子体质谱进行测定。同时对大米样品进行微波消解后测定其中的总砷,通过无机砷及有机砷的总和计算两种前处理方法的回收率,从而对前处理方法进行比较。对磷酸二氢铵、碳酸铵以及磷酸氢二铵等缓冲盐进行选择,并对p H值进行优化,确定最优的流动相条件。结果以12.5 mmol/L磷酸氢二铵作为流动相,调节流动相p H为8.5,流速为1 m L/min,可以将5种无机砷形态完全分离。对两种前处理方法进行比较,发现两种前处理方法的提取效率均大于87.5%,其中酸-热辅助提取法的提取效率相对更高。结论该方法准确、简单,适合大米中无机砷的测定。     

微波辅助消解-固相萃取-氢化物产生-原子荧光光谱联用检测乌龙茶茶叶中无机砷

目的建立微波辅助消解-固相萃取-氢化物产生-原子荧光光谱法测定乌龙茶茶叶中无机砷的分析检测方法。方法以0.06 mol/L HNO_3-3%H_2O_2为消解液,在最大微波功率800 W下,120℃微波消解35 min,提取茶叶中的无机砷,并基于As(Ⅲ)、As(Ⅴ)、一甲基砷(monomethylarsonic acid,MMA)和二甲基砷(dimethylarsinic acid,DMA)解离常数的差异,通过强阴离子交换柱(strong anion exchange cartridge,SAX)实现无机砷和有机砷的有效分离,最后采用氢化物产生-原子荧光光谱法进行无机砷含量测定。结果在0~30μg/L浓度范围内,无机砷的标准曲线方程线性良好(相关性系数r=0.9994),检出限(limit of detection,LOD)为0.208μg/L,样品加标回收率在95.7%~103.6%,相对标准偏差为1.8%~6.8%。结论该方法采用微波辅助消解结合固相萃取提取、分离茶叶中无机砷,具有效率高、成本低、易操作等优点,且可实现乌龙茶茶叶中无机砷高选择性、高灵敏度的分离分析检测。     

海产品中无机砷测定方法的研究

目的比较甲醇溶液和三氟乙酸(TFA)溶液对海产品中砷化合物的提取能力,提出海产品中无机砷测定方法,为修订GB/T 5009.11食品中无机砷的测定方法提供依据。方法以不同比例的甲醇溶液和2mol/L TFA溶液为提取剂,超声提取或热浸提后,以正己烷萃取除去脂质成分,萃取液以N2浓缩或减压旋转蒸发至近干,以超纯水溶解残渣,过滤后进样。以20mmol/L磷酸二氢铵(pH6.0)为流动相,以Hamilton PRPX-100离子色谱柱分离,采用液相色谱-原子荧光光谱法(LC-AFS)测定。结果不同比例的甲醇溶液和2mol/L TFA溶液对海产品中砷化物的提取能力存在差异。2mol/L TFA溶液热浸提对无机砷的提取效果优于50%和90%甲醇溶液,且在提取过程中保持样品中主要砷化物形态稳定。采用2mol/L TFA热浸提海藻样品,其无机砷测定结果的FAPAS国际比对考核Z评分为0.3。结论以2mol/L TFA溶液为提取剂,热浸提2h后,采用液相色谱-原子荧光光谱法测定海产品中无机砷含量,方法特异性强,结果准确可靠。     

液相色谱-原子荧光光谱法检测大米中的无机砷

目的:优化液相色谱-原子荧光光谱法检测大米中无机砷的实验条件。方法:选择7%的盐酸作载流液,光电倍增管高压290 V,载气流速400 mL/min,通过液相色谱-原子荧光光谱法(LC-AFS)对大米中的无机砷进行测定。结果:在实验浓度范围内,线性关系良好,相关系数在0.999 5～0.999 7,检出限[As(Ⅲ)]为0.02 mg/kg和[As(Ⅴ)]为0.02 mg/kg,均有较好的线性及较高的灵敏度。满足大米中的无机砷分析的要求。     

液相色谱-原子荧光光谱法对大米中无机砷的测定

本文采用液相色谱-原子荧光光谱法对大米中无机砷进行测定。方法:采用稀硝酸提取样品中的无机砷,以液相色谱分离目标物,通过与KBH_4在酸性环境下反应得到气态砷化合物后,采用原子荧光光谱仪进行测定。结果:大米中无机砷含量在0~100.0 ng/mL浓度范围内线性关系表现良好,砷酸盐、亚砷酸盐回收率分别为99.2%~102.1%、97.9%~101.0%,重复性分别为1.34%~2.15%、0.81%~2.23%,检出限分别为0.022 9 mg/kg、0.007 2 mg/kg,定量限分别为0.057 2 mg/kg、0.017 9 mg/kg。结论:该方法具有较高准确度和精密度,在大米中无机砷的测定中十分适用。     

高效液相色谱-电感耦合等离子体质谱法测定婴幼儿谷类辅助食品中无机砷及其他砷形态

目的 建立高效液相色谱-电感耦合等离子体质谱法测定婴幼儿谷类辅助食品中无机砷及其他砷形态的分析方法。方法 婴幼儿谷类辅助食品经0.15 mol/L硝酸溶液提取后, 采用阴离子分析柱, 以不同浓度的碳酸铵溶液作为流动相进行梯度洗脱分离, 用高效液相色谱-电感耦合等离子体质谱进行定性和定量分析。 结果 建立的5种砷形态分析方法在0~100 μg/L范围内具有良好的线性关系, 相关系数r>0.999, 加标回收率在89.0%~110.0%, 相对标准偏差(relative standard deviation, RSD)<5%。婴幼儿谷类辅助食品中砷形态以无机砷为主, 在调查的样品中无机砷的含量均远低于国家食品标准的限量。结论 该方法简便、准确, 适用于婴幼儿谷类辅助食品中无机砷及其他砷形态的测定及食品安全的实际监测。     

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。     

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。     

稻谷中无机砷的两种提取方式检测结果对比

在进行稻谷中无机砷含量检测过程中,发现采用恒温干燥箱在温度90℃、时间2.5 h进行无机砷提取时,质控样品大米粉的检测结果低于标准值,提取效果不理想.针对此现象采用液相色谱-原子荧光光谱法(LC-AFS)对不同无机砷含量的稻谷样品,采用恒温水浴震荡和恒温干燥箱两种方式进行无机砷提取,并对检测结果进行了对比.检测结果表明...     

原子荧光光谱法测定糙米粉中总砷及无机砷的含量

目的 建立原子荧光光谱法测定糙米粉中总砷及无机砷含量的分析方法。方法 糙米粉经烘干称取后, 用硝酸高氯酸硫酸混合湿法消解快速进行总砷前处理, 用1%硝酸水浴热提取进行无机砷前处理, 分别利用原子荧光光谱法及液相色谱-原子荧光光谱法进行总砷和无机砷的测定。结果 总砷在6.0~20.0 μg/L浓度范围内, 无机砷在10.0~100.0 μg/L浓度范围内均具有良好的线性关系(r＞0.999), 大米粉质控样测定值总砷0.26 mg/kg及无机砷0.17 mg/kg, 均在参考值允许范围内, 回收率范围为92.3%~127.1%, 均具有较高的回收率。结论 优化湿法消解处理能较高效地得到准确的测定结果, 糙米粉中无机砷经热提取及流动相环节的优化后, 也可得满意检测结果。     

Speciation of inorganic arsenic species and total inorganic arsenic in rice using microwave-assisted dispersive liquid–liquid micro-extraction and electrothermal atomic absorption spectrometry

Human exposure to inorganic arsenic (iAs) via rice consumption is of increasing concern. In the present study, microwave-assisted dispersive liquid–liquid micro-extraction (MADLLME) and electrothermal atomic absorption spectrometry (ETAAS) were developed for the speciation of iAs in rice samples. After microwave-assisted digestion, the As(III) ion reacted with diethyldithiophosphoric acid (DDTP) to form an As–DDTP complex and was extracted at the same time. Some parameters affecting digestion, complex formation, and extraction were studied and optimised. Under the optimised conditions, a detection limit of 0.2 µg kg^?1 with a correlation coefficient of 0.9901 were obtained with a calibration curve in the range of 0.5–200 µg kg^?1. Total iAs was determined after reduction of As(V) to As(III) with sodium thiosulfate and potassium iodide, and As(V) was calculated by difference. The proposed extraction procedure was successfully applied for the determination of iAs ions in certified reference materials (NIST CRM 1568a and NMIJ CRM 7503a) and 10 rice samples produced in Iran and other Asian countries.     

Evaluation of a nitric acid-based partial-digestion method for selective determination of inorganic arsenic in rice

Arsenic (As) uptake in human occurs via the food chain mainly. The Joint FAO/WHO Expert Committee on Food Additives has established the provisional tolerable weekly intake level for As as an inorganic As (iAs) value, because iAs in food is much more toxic than organic As. In this study, we studied an acid based partial-digestion method for the complete extraction of arsenicals from rice. HPLC/ICP-MS was used to determine the concentration of iAs selectively. The conditions adopted to extract arsenicals from a 0.5 g of finely ground rice sample were addition of 2 mL of 0.15 mol/L nitric acid and heating at 80 degrees C for 2 hr. The LOD and LOQ for iAs were 0.0024 and 0.0079 mg/kg dry weight, respectively. Recovery studies showed good accuracy. When the method was applied to ten short-grain brown rice samples, the iAs concentrations were 0.108-0.227 mg/kg dry weight and the total As concentrations were 0.118-0.260 mg/kg dry weight. Although dimethylarsinic acid was also detected in most samples, the percentage of iAs content in total As content was 62.2-96.3%. Thus, iAs was the principal As species in the short-grain brown rice samples tested.     

HPLC-ICP-MS结合微波酸提取分析测定干制食用菌中砷的形态

本文将微波酸提取与高效液相色谱-电感耦合等离子体质谱法联用技术相结合,建立了一种简单、高效的分析方法用于检测干制食用菌中砷的形态化合物。通过对提取方式比较和提取条件的优化,进而验证方法的精密度、检出限、准确度和加标回收率。结果表明:采用微波酸提取方式,既能满足提取效率,又能保证了各砷形态之间不发生转变。在10 min内实现亚砷酸根（As（Ⅲ））、砷酸根 （As（V））、一甲基砷（MMA）、二甲基砷 （DMA）、砷甜菜碱（AsB）、砷胆碱（AsC）的分离。线性关系良好（r>0.9990） ,相对标准偏差（RSD%）<10.0%,定量限分别为0.009、0.012、0.013、0.010、0.011、0.010 mg/kg。以羊肚菌、黑松露两种基质进行加标回收实验,回收率在83.6～105.5%之间;采用两种标准物质验证了方法的准确性好。本方法前处理简单、分离效果、精密度好、准确度高,适用于干制食用菌中砷形态的分析测定,为扩容国标方法适用范围提供了一种新的检测方法和推动食用菌无机砷限量值的制定提供基础数据。     

An evaluation of extraction techniques for arsenic in staple diets (fish and rice) utilising both classical and enzymatic extraction methods

Enzymatic extraction methods were evaluated with classical extraction approaches for the determination of arsenic in food. The extraction efficiency for total arsenic was determined by analysing CRM materials DORM-3 fish protein, NIES 106 rice flour and GBW10015 spinach. These were compared with total arsenic concentration determined using microwave-assisted acid digestion and ICP-MS. The total arsenic concentrations in the CRM materials were in good agreement with the certified values. Enzymatic hydrolysis using trypsin has been successfully employed to extract arsenic species in DORM-3 and fish samples. Whilst this method of hydrolysing the proteins worked well for the fish samples, an alternative approach was required to facilitate the digestion of cellulose in plant materials. However, enzymatic extraction using cellulase was found to give unsatisfactory results for both the NIES and GBW10015 CRM materials. Dilute nitric acid (1% HNO₃) was found to give a more efficient extraction for arsenic species in the same CRM materials and rice samples. The study was extended to evaluate a range of real samples. Total arsenic concentrations in 13 different types of fish tissue were determined following microwave-assisted acid digestion using nitric acid/hydrogen peroxide, followed by measurement using HPLC-ICP-MS for speciation analysis. The results obtained for fish were in the range of 3.53–98.80 µg g^?1 As (dry weight). Similarly, the results of 17 rice samples were in the range of 0.054–0.823 µg g^?1. This study demonstrates the importance of selecting an appropriate extraction technique for the quantitative measurement of arsenic species in food.     

Dynamic microwave-assisted extraction coupled on-line with clean-up for determination of caffeine in tea

A rapid method based on dynamic microwave-assisted extraction (DMAE) coupled on-line with clean-up was developed for the determination of caffeine in tea samples. A TM₀₁₀ microwave resonance cavity was applied to concentrate the microwave energy. An extraction vessel was placed in microwave irradiation zone of the TM₀₁₀ microwave resonance cavity. A silica gel column connected with the extraction vessel was used to remove chlorophyll in tea. The extraction and clean-up procedures were carried out simultaneously in a single step. The DMAE parameters were optimized by the Box-Behnken design. The maximum extraction efficiency was achieved using 70 W of microwave power, 3.5 mL of extraction solvent and 1.0 mL min⁻¹ of extraction solvent flow rate. The limit of detection obtained is 0.012 mg g⁻¹. The RSDs of intra- and inter-day of eight kinds of tea samples are 2.7%-5.4% and 5.1%-7.3%, respectively. The recovery of caffeine in the tea samples is in the range of 88.2%-99.3%.The proposed method has selectivity and sensitivity and considerably less labor and time for determination of caffeine in tea compared with conventional extraction methods, such assoxhlet extractionand liquid-liquid extraction.     

氢化物发生-电感耦合等离子体串联质谱法分析大米中的无机砷

建立氢化物发生-电感耦合等离子体串联质谱(inductively coupled plasma-tandem mass spectrometry,ICP-MS/MS)法直接测定大米中无机砷含量的高通量分析方法.采用硝酸-双氧水提取大米样品中的无机砷,以5 mol/L盐酸作为预还原剂将砷(V)还原为砷(III),在多模式...     

稻米中无机离子镉的HPLC-ICP-MS检测技术研究

研究建立了高效液相色谱-电感耦合等离子体-质谱联用技术（HPLC-ICP-MS）用于稻米样品中无机离子镉（Cd2+）的提取及测 定方法。 样品浸提液为50 mmol/L Tris-HCl缓冲溶液,在50 ℃条件下对稻米样品微波萃取10 min,重复一次,萃取液离心过滤后上机 测定。 使用CS5A阳离子交换柱(配备CG5A保护柱)对稻米样品浸提液中无机离子镉（Cd2+）进行分离,流动相组成为60 mmol/L草酸+100 mmol/L LiOH,方法线性回归方程相关系数R=0.998,精密度实验结果相对标准偏差（RSD）＜10%,加标回收率85.1%～91.6%, 方法检出限为0.005 mg/kg。 采用该方法测定抽检镉超标稻米中无机离子镉（Cd2+）含量,发现其占总镉的比例较低,进一步证实了稻 米中镉主要以有机镉形态存在。     

Determination of Arsenic Species in Edible Mushrooms by High-Performance Liquid Chromatography Coupled to Inductively Coupled Plasma Mass Spectrometry

The content of total arsenic was determined by inductively coupled plasma mass spectrometry after microwave digestion. The results showed that the content of total arsenic was ranged from 0.04 to 212.3 mg kg^?1 in the test edible mushrooms. The content of total arsenic in eight test samples was greater than 0.5 mg kg^?1. However, the toxicity of arsenic is closely related to the chemical form. Therefore, the determination of arsenobetaine, arsenocholine, dimethylarsinic acid, monomethylarsonic acid, arsenite, and arsenate in edible mushrooms was performed on an ion exchange chromatography column (Dionex IonPac AS19) with inductively coupled plasma mass spectrometry as a detector. When water and 50 mM (NH₄)₂CO₃ (pH = 9.7) were worked as a mobile phase, the six arsenic species could be well separated in 20 min. Ultrapure water was selected as extraction solvent for the validation of ultrasound-assisted extraction method due to its advantage of simple, cheap, and high extraction efficiency. Under optimum conditions, the limits of detection were <2.5 μg kg^?1 of the test arsenic species for arsenic, and the recoveries of all six arsenic species were >91.0 % with the relative standard deviation of <5.5 %. The method was applied to 19 different mushroom samples. The results indicated that the total content of arsenic species was basically identical with the content of total arsenic. And arsenobetaine was proved to be the main arsenic species in the test Lentinus edodes-2 sample.     

Inorganic arsenic contents in infant rice powders and infant rice snacks marketed in Korea determined by a highly sensitive gas chromatography-tandem mass spectrometry following derivatization with British Anti-Lewisite

Food Science and Biotechnology - Toxic inorganic arsenic (iAs) has been reported to be present in high quantity in rice and rice-based products. The inorganic arsenic contents in infant foods...