Detection Of Residues In Food Research Articles

A sensitive photoelectrochemical biosensor for pesticide detection based on BiVO4

ABSTRACT A sensitive photoelectrochemical biosensor was constructed for the detection of chlorpyrifos. The sensor was prepared on indium tin oxide (ITO) electrode using photoelectric material bismuth vanadate (BiVO4) and acetylcholinesterase (AChE). It is found that the photocurrent of ITO/BiVO4 electrode was largely dependent on its treatment temperature. The highest anodic photocurrent response of the ITO/BiVO4 photoelectrode was obtained after the treatment at 300°C. The thiocholine, produced in the catalytic reaction at ITO/BiVO4/AChE electrode surface, can greatly enhanced the anodic photocurrent. In addition, the adsorption of chlorpyrifos on the surface of the AChE caused a decrease in the intensity of the photocurrent. Under the optimisation of experimental conditions, the decrease of the photocurrent showed a good linear range from 1 pM to 10 nM under irradiation of visible light. The detection limit is calculated as 0.25 pM with a 10% inhibition rate. The ITO/BiVO4/AChE photoelectrode exhibited high sensitivity, acceptable stability and good reproducibility. The biosensor can be provided to the potential applications for detection of pesticide residues in food.

Determination of 118 pesticide residues in dried wolfberry by gas chromatography-triple quadrupole mass spectrometry in dynamic multiple reaction monitoring mode

枸杞中丰富的营养物质深受广大消费者喜爱,但也极易受到病虫侵害,农药残留问题引起了人们的广泛关注。基质干扰是微量分析的一个难点,高灵敏度和高选择性的色谱-串联质谱技术是复杂基质中微量分析强有力的工具,动态扫描监测模式的优越性逐渐取代传统的多反应监测扫描模式,简便、快速、省时的QuEChERS前处理方法已被广泛应用于食品的农药残留检测中。采用改良QuEChERS法结合动态多反应监测模式(dMRM),建立了同时检测枸杞干果中118种农药残留的气相色谱-三重四极杆质谱分析方法。实验比较了不同加水量、提取溶剂、提取过程中温度提取条件,以及无水硫酸镁吸水剂、乙二胺-N-丙基硅烷化硅胶PSA、十八烷基硅烷键合硅胶C18净化填料添加量时农药的回收率,确定出最优前处理方法。结果表明,5 g样品经10 mL超纯水复水,用10 mL乙腈浸提,于-18 ℃冷冻10 min后,用缓冲体系盐包提取后,经800 mg无水硫酸镁、150 mg PSA、150 mg C18混合填料净化,基质匹配外标法定量。118种农药在一定范围内线性关系良好,相关系数R2≥0.9923,检出限和定量限分别为0.006~28.344 μg/kg和0.021~94.480 μg/kg, 4个添加水平的回收率为64.97%~126.21%, RSDs均小于19%(n=6)。基质效应考察结果表明,82%的农药呈现为基质增强效应,其他为基质抑制效应;9%的农药表现为强基质效应,其他为中等或弱基质效应;采用基质匹配标准曲线校正,可有效降低基质效应的影响。应用建立的方法测定10批枸杞样品,全部样品有农药检出,共检出农药22种。该方法操作简便快速,准确可靠,适用于枸杞干果中农药多残留的日常检测和快速筛查。

Germination assay of Bacillus amyloliquefaciens as a spore-based biosensing method for detection of cell wall destruction antibiotics

Dormant bacterial spores can sense their environments and under favorable conditions exchange their cycle from spore state to germinated one through the processes of germination and outgrowth. Here, the capability of spore germination is used to design an antibiotic bio-sensing system. Germination assays were carried out by reduction of optical density, release of Dipicolinic acid and respiration test under different germinats and various concentrations of Penicillin as a germination inhibitor. This study showed that although current germinants are not properly useful for germination of Bacillus amyloliquefaciens in starch media, presence of a small amount of cell wall destruction antibiotics (25 µg/ml) can accelerate germination but prevent outgrowth of germinated spores. So, the germinated spores cannot use the starch and stain blue with iodine reagent. This phenomenon is beneficial for detection of antibiotic residues in food and feed which are severe problem for consumers or by giving rise to the expansion of antibiotic resistances.

Detection of GM residues in foods derived from soy in Uberlândia - MG

Soy is a product of great economic importance, since it covers a variety of marketing fields that permeate the human and animal consumption for the processed food industry. Thus, to maximize production and improve product quality, the legume is a frequent target for genetic modification. The concern with the long-term effect of the transgenic product, beyond the consumer's right to know about the product you eat demanded a law regulating the presence of these products in the market. Existing legislation in Brazil indicates that rates of GM products, with more than 1% should be informed on food labels. To ensure compliance with the law are necessary protocols able to identify and quantify the waste. Therefore, this project aims to evaluate the protocols of DNA extraction by CTAB method proposed by Ferreira and Grattapaglia [1] and the method proposed by FERRARI et al [2], as well as detect PCR transgenic residues in processed foods derived from soybeans. After extraction, DNA was quantified by spectrophotometry and absorbance ratio 260/280 nm was analyzed to determine the quality of the samples. Furthermore, the technique was used to eletrofrese agarose gel to compare the quality of DNA samples of soybeans with fresh samples processed soybeans. The protocol for DNA extraction from FERREIRA & GRATTAPLAGLIA was more efficient compared to the yield of DNA extracted from different samples, but in relation to quality of DNA both protocols showed similar results. The detection of residues in transgenic samples showed that the PCR amplified only the lectin gene (endogenous), confirming that the samples contained soy, but did not amplify the exogenous gene, suggesting that the samples did not contain residues of transgenic.

Study on Quantitative Detection of Pesticide Residue Based on Spectroscopy Technology of Differential Absorption

For the domestic food safety problem that caused by the pesticide residues in food, it’s very important to find a convenient and cost-appropriate detection technology. At present, spectroscopy absorption technology has been used for detection of pesticide residues in food. However, there are some deficiencies such as the quantitative detection and the measurement precision. This experiment that based on differential absorption is completed by using miniature fiber optic spectrometer and spectrophotometer, and then the pesticide DDVP is also measured quantitatively. Thus the pesticide residue detection technology that based on spectroscopy absorption is improved to adjust to the practical application.

An RNA-Aptamer-Based Assay for the Detection and Analysis of Malachite Green and Leucomalachite Green Residues in Fish Tissue

A robust screening assay employing solid phase extraction (SPE) followed by a novel aptamer-based procedure is presented for the rapid detection and semiquantitation of the triphenylmethane dye, Malachite Green (MG) and its primary metabolite Leucomalachite Green (LMG) in fish tissue. To the authors' knowledge, this is the first reported use of an RNA aptamer for the development of a diagnostic assay for the detection of chemical residues in food. The aptamer based screening assay is found to be highly specific for MG; but has negligible affinity for the LMG metabolite. However, because the LMG metabolite is lipophilic and known to be highly persistent in tissues, an oxidation step has been incorporated within the sample cleanup procedure to ensure that all LMG residues are converted to MG prior to measurement. This article provides evidence that an oligonucleotide aptamer can be used as an alternative recognition element to conventional antibodies with application to the detection of residues in food. Furthermore, this finding has the future potential to reduce the number of animals currently being used in the production of antibodies for immunodiagnostic kits.

Validated Enzyme-Linked Immunosorbent Assay (ELISA) for Detection of Undeclared Cashew Nut Residues in Foods

Validated Enzyme-Linked Immunosorbent Assay (ELISA) for Detection of Undeclared Cashew Nut Residues in Foods

TOXIDEZ, DEGRADAÇÃO NO MEIO-AMBIENTE E MÉTODOS ELETROANALÍTICOS DE DETECÇÃO DO PESTICIDA CARBARIL

Este artigo apresenta breve revisão de literatura sobre o inseticida carbaril, muito utilizado na agricultura brasileira. Foram abordados seus efeitos tóxicos em humanos e animais, bem como sua degradação no meio-ambiente. Explorou-se a determinação de seus resíduos por métodos eletroanalíticos, utilizando os eletrodos de platina, mercúrio, diamante dopado com boro e eletrodos modificados, tais como os biossensores. O conhecimento das formas de degradação possibilita a elaboração de processos físicos e químicos visando o tratamento de águas e solos poluídos. Além disso, devido ao uso intenso do carbaril em culturas de frutas e vegetais, também é necessário o desenvolvimento de metodologias sensíveis para a detecção de resíduos nesses alimentos.

Immunobiosensor analysis- of clenbuterol in bovine hair

Due to the potential speed and flexibility of surface plasmon resonance (SPR)-biosensor analysis, the technique is currently being exploited for detection of residues in food. In the present study an antibody-based inhibition assay for analysis of clenbuterol in cattle hair was developed using a Biacore 2000 instrument. Analysis of clenbuterol with and without enhancement with a secondary antibody was compared. A fast extraction method for hair, which enabled direct analysis in the biosensor with no clean up other than microscale ultrafiltration was developed. In contrast to most of the published methods in the area, no organic solvent or solid phase extraction step was needed. The biosensor method was validated by analysis of hair samples from animals treated with clenbuterol and the results were compared to results from GC-MS analysis. The correlation was good (r 2=92.7%). The detection limit of the new method was 10 ng g−1 hair.

Validated ELISA for detection of undeclared walnut residues in food

Validated ELISA for detection of undeclared walnut residues in food

Rapid detection of neurotoxic insecticides in food using disposable acetyicholinesterase-biosensors and simple solvent extraction.

The extensive use of pesticides to protect agricultural crops necessitates reliable tools for the detection of residues in food and water, thus ensuring environmental protection and consumer safety. Neuroinhibitors such as organophosphates and carbamates in particular, represent a potential hazard to human health. These compounds are frequently found in food, but conventional methods of analysis are limited as they are either time consuming or not sufficiently sensitive. As a result, a rapid and sensitive biosensor test based on AChE-inhibition was developed. The disposable AChE-biosensor was directly applied in solvent extracts of food samples using isooctane as extraction solvent. A complete assay could be performed in less than 2 h. Recovery rates of 84% were obtained in tests with spiked orange juice samples. Tests in food samples with a lower water content resulted in reduced recovery rates (44% for peach pap baby food). Phosphorothionate insecticides in food could be detected after direct oxidation with N-bromosuccinimide and solvent extraction. The assay displayed a detection limit of 2 microg/kg paraoxon, which was sufficient for the monitoring of maximum residue limits in food according to EU regulations.

Sensor chip preparation and assay construction for immunobiosensor determination of beta-agonists and hormones.

Immuno-sensing with optical biosensors is a new technique that is currently being exploited for detection of residues in foods. The present study explores the possibilities of obtaining fast screening assays for a number of illegal veterinary drug residues at low concentrations. Analyte specific sensor surfaces were prepared and used to construct inhibition assays with various antibody reagents. Assay sensitivities for calibration curves in buffer solutions around 0.5 ng ml(-1) in terms of IC50 (concentration of the inhibitor) values were achieved for the beta-agonist clenbuterol and the hormone analogues ethinylestradiol and trenbolone. Assay performance was optimised by evaluating factors such as sensor surface ligand density, active antibody concentration, biosensor flow rate, etc.

New control system for the detection of residues in foods: Matrix tablets: [formula omitted], V.Calderón 1, V. Ruz, M.E. Gil-Alegre, M.A. Camacho and A.I. Torres-Suárez. Pharmacy and Pharmaceutical Technology Department, Faculty of Pharmacy, Complutense University of Madrid, 28040 Madrid, Spain. 1 Food National Center, Carlos III Health Institute, Madrid, Spain

New control system for the detection of residues in foods: Matrix tablets: [formula omitted], V.Calderón 1, V. Ruz, M.E. Gil-Alegre, M.A. Camacho and A.I. Torres-Suárez. Pharmacy and Pharmaceutical Technology Department, Faculty of Pharmacy, Complutense University of Madrid, 28040 Madrid, Spain. 1 Food National Center, Carlos III Health Institute, Madrid, Spain

A Flame Ionization Detector Highly Selective and Sensitive to Phosphorus—A Sodium Thermionic Detector

Abstract A selective detector for use in a gas chromatography system for the detection of organophosphate pesticide residues in foods has been developed and investigated. The device consists of a conventional detector with a coat of a sodium salt fused onto the electrode. There are two requirements: sodium must be present and it must be heated. This sodium thermionic detector is highly selective in response to phosphorus in an organic compound. Other atoms generate some response also, but the relative sensitivity to phosphorus is so great that the sensitivity of the detector can be adjusted to measure essentially only phosphorus. The detector also responds selectively to halides but to a much lesser degree. The detector can detect and measure both organophosphate and chlorinated pesticide residues in a sample extract.