Rapid sample preparation procedure for As speciation in food samples by LC-ICP-MS

This paper describes a rapid method for arsenic (As) speciation by LC-ICP-MS in several types of food samples. Prior to analysis, samples were milled and the As species extracted from biological tissues by sonication in only 2?min with a solution containing MeOH (10%, v/v) plus HNO₃ (2%, v/v). As species were separated by LC using an anion exchange column. Method detection limits for AsB, As³⁺, DMA, MMA and As⁵⁺ were 1.3, 0.9, 0.6, 0.7 and 0.8?ng?g^?1, respectively. Method accuracy and precision were traceable to Certified Reference Materials SRM1577 bovine liver from the National Institute of Standards and Technology, CE278 mussel tissue from the Institute of Reference Materials and Measurements and DOLT-3 dogfish liver tissue and DORM-3 fish protein from the National Research Council of Canada. Finally, the method was applied to speciate As in food samples (egg, fish muscle, beef and chicken) purchased in Brazilian markets.     

食品中重金属元素形态分析前处理与 检测研究进展

重金属的摄入可使人体的蛋白发生不可逆转的变性而危害人体健康。近年来, 食品中具有生物毒性的重金属含量越发受到关注, 但重金属的总量往往很难表示其污染特性及危害。食品中重金属元素形态决定其生物可利用率、毒性和迁移, 是食品安全检测关注的重要内容。本文从样品前处理、分析检测、联用技术等方面综述了食品中重金属的元素形态分析方法, 包括固相萃取等前处理技术、电感耦合等离子体原子发射光谱法等分析检测技术及高效液相色谱-电感耦合等离子体质谱联用等联用技术, 介绍了各种方法的原理、优点及不足。最后, 探究了其研究发展方向。生物、材料等领域的发展将推动重金属形态分析样品前处理技术的进步, 而联用技术将成为未来分析检测技术的发展方向。     

食品中重金属检测及样品前处理方法研究进展

重金属污染主要指由汞、镉、铅、铬等生物毒性显著的元素引起的污染,随食品进入人体后会导致多种疾病。随着人们对食品安全的要求不断提高,食品中重金属污染问题受到更多的关注,各类食品中重金属含量和形态的检测需求日益增加,发展便捷高效的重金属检测方法十分必要。本文综述了近年来受到广泛应用的食品中重金属检测技术及样品前处理方法,重点介绍了检测技术中原子吸收光谱法、原子荧光光谱法、电感耦合等离子体原子发射光谱法、电感耦合等离子体质谱法和高效液相色谱法的方法原理、应用实例和优缺点。同时,对样品前处理方法中常用的消解技术和重金属富集技术进行了概述,并对目前的研究热点和未来的发展方向进行了总结和展望,以期为各类食品中重金属检测技术的选择提供参考。     

Improvement of a sample preparation procedure for multi-elemental determination in Brazil nuts by ICP-OES

Various sample preparation procedures, such as common wet digestions and alternatives based on solubilisation in aqua regia or tetramethyl ammonium hydroxide, were compared for the determination of the total Ba, Ca, Cr, Cd, Cu, Fe, Mg, Mn, Ni, P, Pb, Se, Sr and Zn contents in Brazil nuts using inductively coupled plasma optical emission spectrometry (ICP-OES). For measurement of Se, a hydride generation technique was used. The performance of these procedures was measured in terms of precision, accuracy and limits of detection of the elements. It was found that solubilisation in aqua regia gave the best results, i.e. limits of detection from 0.60 to 41.9 ng ml^?1, precision of 1.0–3.9% and accuracy better than 5%. External calibration with simple standard solutions could be applied for the analysis. The proposed procedure is simple, reduces sample handling, and minimises the time and reagent consumption. Thus, this can be a vital alternative to traditional sample treatment approaches based on the total digestion with concentrated reagents. A phenomenon resulting from levels of Ba, Se and Sr in Brazil nuts was also discussed.     

食品微生物检验样品的采集和制备

通过对样品采集和制备的介绍,保证所检样品的代表性和一致性,提高对整批产品的判定结果的准确率.     

食品分析中样品制备新技术概况

介绍了六种食品分析中样品制备新技术:超临界萃取技术,微波协助萃取技术,固相萃取技术,固相微萃取技术,顶空技术和流动注射分析技术。综述了他们在食品分析中的应用及未来发展趋势。     

环介导等温扩增技术快速检测食品中变形杆菌的研究

采用环介导等温扩增(LAMP)技术,快速检测食品中的变形杆菌。以变形杆菌(CMCC49027)的atpD基因作为靶序列,设计内、外引物,通过肉眼观察白色沉淀,判断检测结果。共对11株致病菌进行特异性实验。结果表明,变形杆菌为阳性,其他10株菌为阴性。采用FTA滤膜制备模板进行LAMP反应,其方法的灵敏度为6.4×102CFU/mL。利用LAMP技术直接检测人工污染的肉制品中的变形杆菌,其检出限为3.6×103CFU/g。本实验所建立的快速检测变形杆菌的LAMP检测方法具有较高的特异性和敏感性,能够满足变形杆菌快速检测的需要。     

低共熔溶剂在食品样品前处理中的应用

低共熔溶剂(DESs)作为近年来新兴的绿色溶剂,因其具有低挥发性、可生物降解、环境友好、成本低和组合灵活等特点,可结合各种萃取技术如超声辅助萃取、微波辅助萃取、中空纤维萃取和固相萃取等, 在预处理过程中有多种应用,不仅可以提高提取效率、降低常规分析的成本,而且减少对人类健康和环境污染影响。本文全面综述了近几年基于低共溶溶剂在样品前处理技术在食品样品分析中的研究进展。     

食品中邻苯二甲酸二（2-乙基己基）酯样品前处理与分析检测方法研究进展

邻苯二甲酸二（2-乙基己基）酯（DEHP）作为常用增塑剂广泛应用于塑料包装材料的生产,但因其具有致癌性、致畸性、致突变性和内分泌干扰毒性,食品中DEHP的分析与检测引起了广泛的关注。本文综述了食品中DEHP的样品前处理方法,包括索氏提取、超声波提取、固相萃取、固相微萃取等,并对其常用检测方法（如液相色谱法、气相色谱法、气相色谱-质谱联用、液相色谱-质谱联用等）的研究进展进行了评述。      

食品样品的采集、初级制备与保存

随着社会的不断发展和进步,人们的生活质量和保健意识也不断提高,消费观也从注重数量向注重质量和安全转变,食品安全问题已成为广大消费者更加关注的问题。因此要确保人民群众可以吃上放心食品,保障人们的身体健康与生命安全,食品检验就成为食品质量控制的一个重要环节,而食品样品的采集、制备与保存等是确保食品检验结果准确、客观的关键性因素。为确保样品能够满足检验的要求,充分反映出产品的质量特性和可塑性,降低检验风险,必须对食品样品的采集过程,样品的初级制备过程,样品的保存条件进行严格的管理,以确保样品的客观性、真实性和可靠性。本文主要综述了食品样品的采集、样品的前期初级制备和样品的保存需要注意的原则、方法,为后续检验工作的进行提供依据。     

ONPG培养基快速测定食品中大肠菌群的研究

目的探讨邻硝基苯-β-D-吡喃半乳糖苷(o-Nitrophenyl-β-D-Galactopyranoside,ONPG)培养基在快速测定食品中大肠菌群的应用。方法比较ONPG培养基和月桂基硫酸盐胰蛋白胨(lauryl sulfate tryptose,LST)肉汤测定大肠埃希氏菌不同时段的结果,使用χ~2-test分析;比较ONPG培养基和LST肉汤测定食品中大肠菌群的结果,使用Wilcoxon配对法分析。结果测定大肠埃希氏菌时ONPG培养基18 h结果与LST肉汤48 h结果无显著性差异(P0.05);测定食品中大肠菌群时ONPG培养基18 h结果与LST肉汤48 h结果无显著性差异(P0.05)。结论 ONPG培养基可用于快速测定食品中大肠菌群。     

Rapid screening of roundup ready soybean in food samples by a hand-held PCR device

Food Science and Biotechnology - Insulated isothermal PCR (iiPCR) method was recently available for rapid on-site detection of roundup ready soybean (RRS; event GTS40-3-2) in food materials and...     

食品采样、制备、样品管理研究中遇到的问题及对策

随着食品安全意识的提升,人们对食品检验提出了更高的要求,其通常包括食品采样、食品制备、样品管理等关键环节.食品采样要保证所采样品具有代表性、时效性、完整性;食品制备要保证制备工具清洁、干燥,不与所制样品发生任何化学反应;样品管理要保证样品存放环境符合相应标准,不同样品按不同储存环境进行存放,其中任何一个环节出现问题,都...     

Rapid DNA preparation from milk and dairy process samples for the detection of bacteria by PCR

In this communication, a rapid, easy pretreatment of milk and dairy process samples is presented in order to detect the microbes present in the samples by the polymerase chain reaction (PCR). It includes the use of commercial membrane cards for the disruption of cells and the storage of DNA, and the inclusion of a card punch in a PCR as the template source. Successful detection of starter, probiotic and pathogen strains in dairy food samples was obtained in PCR by using the membrane-based method for DNA preparation.     

刀式混合研磨仪GM200在样品制备中的应用研究

目的建立蔬菜、水果、鱼类、肉类及粮食谷物类等样品前处理操作规范。方法采用前处理设备德国莱驰刀式混合研磨仪(RETSCH GRINDOMIX GM200),从各类食品样品着手,上机进行反复试验,找到最适的仪器操作参数对样品进行均一化处理。结果蔬菜、水果、鱼类、肉类及粮食谷物等经刀式混合研磨仪GM200研磨后均获得均一性样品,满足后续检测的实验要求(包括元素、农残、兽残等检测项目)。结论采用刀式研磨仪GM200对样品进行预处理,可以进一步地提高样品的均一化程度,更好地保留分析目标化合物,为食品样品中待测组分的提取、净化、浓缩,进行定量、定性分析检测做好充分准备,保证结果的准确性和重现性。     

Cloud point extraction for speciation of iron in beer samples by spectrophotometry

A new method based on the cloud point extraction (CPE) separation and spectrophotometric detection was proposed for the determination of iron species. In this method, Fe(II) reacts with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP) in the presence of EDTA yielding a hydrophobic complex, which then is extracted into surfactant-rich phase. Total iron was determined after the reduction of Fe(III) to Fe(II) by using ascorbic acid as reducing agent. Variable parameters affecting the CPE efficiency were evaluated and optimised. The calibration graph was linear in the range of 5.0–112 μg/L (at 742 nm) for both species. Under the optimised conditions, the detection limits of 0.8 μg/L and 1.0 μg/L and the relative standard deviations of 2.0% and 2.6% (C_Fe(II) = C_Fe(III) = 10 μg/L, n = 5) for Fe(II) and Fe(III) were found, respectively. The proposed method has been applied to the speciation of iron in beer samples with satisfactory results.     

Improved PCR detection of Campylobacter jejuni from chicken rinses by a simple sample preparation procedure

Many food samples and enrichment media are inhibitory to the PCR, thereby lowering its detection capacity. A simple sample preparation method based on buoyant density centrifugation was examined for its application in PCR detection of Campylobacter jejuni from chicken rinse samples. Bacterial cells were spiked at different levels in a mixture of Preston broth and chicken rinse (4:1 ratio) and 0.9 ml of these mixtures were layered over 0.6 ml of gradient medium made from Percoll. PCR sensitivity for bacterial samples treated with this procedure was approximately 10-100 times higher than for samples without treatment. This sample preparation method allowed for the detection of C. jejuni from 26 of 31 naturally contaminated chicken samples after a 20-24-h enrichment period in Preston broth, compared with only 14 positives for untreated samples. In addition, the effect of Oxyrase on the growth and PCR detection of C. jejuni was examined. While Oxyrase significantly enhanced the growth and the PCR signals of C. jejuni in pure culture, it appeared not to improve the PCR detection of C. jejuni in naturally contaminated chickens.     

食品中化学危害物检测的样品前处理方法选择及开发策略

食品中化学危害物种类多,含量一般在痕量和超痕量水平;食品基质复杂,要在低含量水平获得可靠的检测结果,选择合适样品前处理技术至关重要。本文针对不同类别化合物的检测需要,根据不同食品基质的特性及分析目的,依靠近10年来食品化学危害物的样品前处理方法开发经验,探讨样品前处理技术的选择,综述前沿技术进展。提出基于“食品基质”和“分析目标物”的具有实际应用性的前处理方法选择策略,并结合应用实例,提出针对性前处理方法开发的建议,旨在为基层技术人员选择可靠的前处理方法提供借鉴。     

Applications of sample preparation techniques in the analysis of pesticides and PCBs in food

Pesticides and polychlorinated biphenyls (PCBs) are found in various parts of the environment in quite small concentrations, but they accumulate and thus become a threat to human health and life. A review is focused on the application of some popular techniques for sample preparation in analysis of these compounds in food. Even with the emergence of advanced techniques of final analysis, complex matrices, such as food, require extensive sample extraction and purification. Traditional sample preparation techniques are time consuming and require large amount of solvents, which are expensive, generate considerable waste, contaminate the sample and can enrich it for analytes. There have been many sample preparation techniques proposed to meet the requirements connected with the multiplicity of food. Optimal sample preparation can reduce analysis time, sources of error, enhance sensitivity and enable unequivocal identification and quantification. Sample extraction and purification techniques are discussed and their most recent applications in food analysis are provided. This review pointed out that sample preparation is the critical step.     

高效液相色谱-串联质谱法快速测定食物中毒样品中的百草枯和敌草快

目的建立高效液相色谱-串联质谱法快速检测食物中毒事件中常见样品(如食品、血液及尿液等)中百草枯和敌草快的分析方法。方法分别以乙酸乙酯为溶剂提取食品和尿液样品、以乙腈为溶剂提取血液样品中的百草枯和敌草快,提取液氮吹浓缩至近干,加入流动相复溶,再经0.22μm滤膜过滤。采用WATERS ACQUITY UPLC BEH Amide色谱柱分离,以乙腈(A)-100 mmol/L甲酸铵溶液(含0.05%甲酸)(B)(60:40,V:V)为流动相等度洗脱,多反应模式监测,外标法定量。结果百草枯和敌草快在2.0~100μg/L质量浓度范围内线性关系良好,相关系数为0.9971~0.9999。百草枯和敌草快的检出限(S/N=3)分别为1.0μg/L和0.3μg/L,定量限(S/N=10)分别为3.0μg/L和1.0μg/L。加标水平为2.0、10.0、80.0μg/L时,百草枯和敌草快回收率分别为82.4%~98.4%和90.1%~103.5%,相对标准偏差分别为0.8%~5.1%和1.0%~4.2%。结论本方法建立的分析过程样品前处理简单、快速、准确,适用于食品、血液和尿液中的百草枯和敌草快的同时测定。