جستجوی مقالات مرتبط با کلیدواژه « Food analysis » در نشریات گروه « علوم پایه »

Due to the widespread use of veterinary drugs and antibiotics in animal husbandry, one of the most critical problems in ensuring food safety is the presence of residual antibiotic traces in animal products. Concentrations of such traces in food products pose a danger to both humans and the environment as a whole. Irrational use of antibiotics in agriculture stimulates resistant bacteria that can cause infectious diseases in humans and animals that cannot be treated with modern drugs. Due to the potential risk to human health in many countries, maximum permissible limits for the content of residual traces of antibiotics are regulated. This review aimed at investigating the recent publications in the field of identification of residual antibiotic traces in food. Various types of high-performance liquid chromatography (HPLC) and tandem mass spectrometry (MS/MS) combined with solid-phase extraction were mainly used for the quantitative determination of analytes. Methods of enzyme immunoassay, capillary electrophoresis, and infrared spectroscopy with Fourier transform, biosensor, and fluorescence analysis methods are also presented. It is shown that the development of new susceptible, accurate, simple, and cost-effective methods for the determination traces of antibiotics in food remains an urgent task and is highly demanded in the modern world.

Folic acid is an important food additive found in most food products. This research study focused on making a powerful analytical device to determine the folic acid concentration in food products. An electrochemical amplified sensor based on paste electrode (PE) modified with CuO-CNTs and 1-butyl-2,3-dimethylimidazolium hexafluorophosphate (BDHFP) was fabricated and used to study the electro-oxidation of folic acid. Oxidation current of folic acid was improved about 2.8 times at PE/M/CuO-CNTs/BDHFP compared with that of the PE. In addition, an irreversible and pH dependent oxidation signal was detected for redox reaction of folic acid at surface of PE/M/CuO-CNTs/BDHFP. Active surface area of PE was increased from 0.11 cm2 to 0.18 cm2 after modification with CuO-CNTs and BDHFP. Differential pulse voltammetric (DPV) signals displayed a linear dynamic range 3.0 nM–250 µM with detection limit 0.8 nM for measurement of folic acid. To study the ability of the PE/M/CuO-CNTs/BDHFP to determine the folic acid in real samples, apple and orange juices were selected and recovery data between 99.29%-101.6% confirm high performance ability of PE/M/CuO-CNTs/BDHFP for determination of folic acid in real samples.

Gallic acid is one of the most abundant phytochemical in nature with anticancer activity against the prostate cancer. In this research work, carbon paste electrode (PE) modified with CdO/CNTs nanocomposite and 1-hexyl-3-methyl imidazoliume bromide (HMIZBr) design and made-up for determination of gallic acid in food samples. Electrochemical behavior of gallic acid at the CdO/CNTs/HMIZBr/PE was investigated in aqueous solution using the voltammetric methods. The gallic acid oxidation signal was improved about 2.82 times on the surface of the CdO/CNTs/HMIZBr/PE compared with that of the PE. Using differential pulse voltammetric method as sensitive strategy, the CdO/CNTs/HMIZBr/PE showed linear dynamic range 0.004-500 µM with detection limit of 0.9 nM to determine the gallic acid. In addition, real sample analysis data showed the powerful ability of the CdO/CNTs/HMIZBr/PE to determine the gallic acid in white rice.

Herein, a convenient, simple, rapid, labor efficient and economical salt-induced homogeneous liquid-liquid microextraction technique coupled with high-performance liquid chromatography-photo diode array detection system was developed for sample preparation, extraction and quantitative determination of diazinon and cypermethrin in milk samples. In a single step, a homogeneous solution containing acetone and dichloromethane was used for the extraction of analytes and precipitation of milk proteins. This solution was broken by the addition of sodium chloride as phase separator agent. Several variables that influence the extraction efficiency such as composition of homogeneous solution, concentration of phase separator agent and extraction time were fully evaluated and optimized. Under optimal conditions for analysis of two pesticides, matrix-matched calibration curves with dynamic linear ranges of 0.065-1300 µg L-1, limit of detection of 0.018-0.03 µg L-1, and the limit of quantification of 0.065-0.1 µg L-1 were obtained. The enrichment factors and extraction recoveries were 158-174 and 79-87%, respectively. Precision and accuracy of the method based on RSDs and REs for three concentration levels of both pesticides were achieved between 2.7-12.3% and 6.1-8.3% (n=5), respectively. The represented method was successfully applied for the simultaneous assay of diazinon and cypermethrin in different milk samples.

Foodstuffs analysis is very important due to population growth and increasing consumer demand for safety and nutritional excellence. The Analysis of different compounds in foodstuffs is so difficult without using sample preparation techniques. Traditional techniques require large amounts of toxic organic solvents. As a result, they are not only expensive but also environmentally unfriendly and they generate a considerable amount of waste. Nowadays efforts are being focused on development of microextraction techniques. Different microextraction techniques such as solid phase microextraction (SPME), stir bar sorptive extraction (SBSE), and liquid phase microextraction (LPME) have found an important place in sample preparation because of their inherent advantages over the conventional procedures. In particular, they have been applied with successfully for the analysis of food samples despite their complexity. The review discusses different microextraction approaches used in analysis of chemical compounds and metal ions in foodstuffs. It summarizes the application of microextraction techniques in food analysis in details as possible.

In this research the novel potentiometric sensors have been evaluated for the selective determination of Cochineal Red A (CRA) in colored food. PVC membrane (PME) and coated graphite electrode (CGE) have been prepared based on tetraphenylphosponium-CRA ion pair as the electro active substance. The electrodes reveal linear emf-pCRA responses over wide concentration ranges of (1.0×10-4-1.0×10-1 M with a slope -19.0 mV decade-1 for PME) and (1.0×10-6-1.0×10-1 M with a slope -20.2 mV decade-1 for CGE) and limits of detection of 7.8×10-5 for PME and 8.0×10-7 for CGE. The potentiometric responses were independent of the pH of the test solution in the pH range 4-7. The proposed electrodes showed very good selectivity over a wide variety interfering ions. Electrodes have been successfully applied to the determination of Cochineal Red A in food products by direct potentiometric method. The results were in good agreement with the value obtained by using the official method (HPLC measurements).