Application of Graphene Oxide Reinforced Hollow Fibers as a Novel Electromembrane Extraction Method for Quantitative Analysis of Dicyandiamide in Infant Formula

Dicyandiamide (DCD) is a nitrogenous compound which is generally used as a fertilizer, antimicrobial and nitrogen enrichment agent in soil. Grass and drinking water contamination with DCD may lead to presence of the chemical residues in milk and infant formula. The aim of this study was to investigate a rapid, simple and accurate method for quantitation of DCD in infant formula using electromemebrane extraction with reinforced hallow fiber by graphene oxide (GO-EME). The extraction method was optimized by solvent, graphene oxide concentration, voltage, stirring speed, pH and time parameters. After extraction, DCD was analyzed by HPLC coupled with UV/Vis detector. The analytical method validation parameters including accuracy, precision, LOD and LOQ were determined to ensure the method's validity.The calibration curve with a correlation ratio of 0.999 was obtained. The recoveries were from 78.0% to 80.0%. The LOD and LOQ were 0.04 mg L-1 and 0.1 mg L-1. This study indicates that the graphen oxide-electromembrane extraction is a simple, accurate and rapid method for determination of DCD in infant formula

Simultaneous Determination of 17 Pesticide Residues in Rice by GC/MS using a Direct Sample Introduction Procedure and Spiked Calibration Curves

Abstract A reliable, rapid and accurate method based on spiked calibration curves and direct sample introduction was developed for determination of 17 pesticide residues in rice by gas chromatography-mass spectrometry single quadrupole selected ion monitoring GC/MS-SQ-SIM. Sample preparation is based on extraction with acetonitrile without clean up. The use of spiked calibration curves for constructing the calibration curve substantially reduced adverse matrix-related effects. The average recovery of pesticides at 6 concentration levels was in range of 97.5-102.1%. The method was proved to be repeatable with RSDr in range of 0.7%-19.8%for all of the concentration levels. The limits of detection and limit of quantifications for all the pesticides were < 10 ng/g and < 25 ng/g, respectively. The developed method was applied for simultaneous determination of the selected pesticides in 23 rice samples collected from Tehran retail market in March 2009. Although many studies have been conducted regarding the determination of pesticides by using GC-MS, this is the first attempt in Iran using GC-MS-SIM technique that successfully can determine 17 pesticides with difference in physicochemical properties in rice

Multi-Residue Analysis of Pesticides in Pistachio Using Gas Chromatography-Mass Spectrometry (GC/MS)

Background: Analysis of pesticide residues in food and other environmental commodities have become an essential requirement for consumers, producers, food inspectors and authorities. This study is focused on validation of an accurate, rapid and reliable method for multi-residual analysis of pesticides in pistachio as a strategic crop for export and one of the main nuts in Iranian food basket. Methods: We developed a "Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method based on spiking blank samples and used the data for drawing calibration curves instead of standard solutions. Sample preparations were developed for determination of 12 pesticide residues in pistachio by gas chromatography-mass spectrometry (GC/MS). Results: Recovery of pesticides at 5 concentration levels (n=3) was in the range of 81.40% - 93.08 %. The method proved to be repeatable in the majority of samples with relative standard deviation (RSD) of lower than 20%. The limits of detection and quantification for all pesticides were 2 ppb and 10 ppb, respectively. Conclusion: The calibration curves of pesticides were linear in the range of 10-500 (ng/g) and correlation coefficient of entire pesticides was higher than 0.994. The recovery of pesticides at 5 concentration levels (n=3) was in range of 81.41- 91.80 %. The method was proved to be repeatable with the majority of RSDs being lower than 20%. The limits of detection and quantification for all pesticides were 2 and 10 ppb, respectively. The recoveries and repeatabilities were in accordance with the criteria set by SANCO Guideline (Commission of the European Communities, 2006)

Effects of different roasting methods on formation of acrylamide in pistachio

Drying and roasting are conventional processes in the nut industry. However, roasting as an important procedure in nuts manufacturing may cause some physicochemical changes in nuts. Acrylamide is one of these chemical compounds that is formed due to the roasting process. Acrylamide is known as a neurotoxicant, carcinogen, and reproductive toxicant. In this study, raw and salted pistachios were roasted under three conditions including hot-air, infrared (IR), and microwave methods. Then, 80 pistachio kernels were analyzed by ultra-high-performance liquid chromatography. The results showed that all samples contained different ranges of acrylamide between 57 ± 0.86 and 851 ± 2.8 μg/kg. Besides, raw pistachios and sun-dried pistachios also contained acrylamide, with the amount of 57 ± 0.86 and 93 ± 1.07 μg/kg, respectively. The highest acrylamide amount was found in raw pistachio (unsalted) roasted by IR method, while lower acrylamide amount observed in the microwave method. The amount of acrylamide in salted and roasted pistachios was less than just roasted pistachios under the same conditions. Finally, in all the treatments, increasing temperature, time, voltage, and power lead to an increase in acrylamide levels. The results showed that acrylamide in the roasted pistachios may cause health problems. This study presents a novel investigation in the effects of roasting conditions (temperature, power, voltage, and time) on acrylamide content in pistachios

Comparison between Different Extraction Methods for Determination of Primary Aromatic Amines in Food Simulant

The primary aromatic amines (PAAs) are food contaminants which may exist in packaged food. Polyurethane (PU) adhesives which are used in flexible packaging are the main source of PAAs. It is the unreacted diisocyanates which in fact migrate to foodstuff and then hydrolyze to PAAs. These PAAs include toluenediamines (TDAs) and methylenedianilines (MDAs), and the selected PAAs were 2,4-TDA, 2,6-TDA, 4,4′-MDA, 2,4′-MDA, and 2,2′-MDA. PAAs have genotoxic, carcinogenic, and allergenic effects. In this study, extraction methods were applied on a 3% acetic acid as food simulant which was spiked with the PAAs under study. Extraction methods were liquid-liquid extraction (LLE), dispersive liquid-liquid microextraction (DLLME), and solid-phase extraction (SPE) with C18 ec (octadecyl), HR-P (styrene/divinylbenzene), and SCX (strong cationic exchange) cartridges. Extracted samples were detected and analyzed by HPLC-UV. In comparison between methods, recovery rate of SCX cartridge showed the best adsorption, up to 91% for polar PAAs (TDAs and MDAs). The interested PAAs are polar and relatively soluble in water, so a cartridge with cationic exchange properties has the best absorption and consequently the best recoveries

Residue Levels and Risk Assessment of Pesticides in Pistachio Nuts in Iran

Background: Pistachio is one of the main nutrients, not only as a strategic crop but also as a main type of nut, in Iranians’ food cycle. The aim of this study was to measure the relative safety of Iranian pistachio based on the standard pesticide’s residue limits, which should be monitored and assessed in the cultivation of pistachio in order to confirm its public health. Methods: Fifty samples of pistachios of different brands were collected from Tehran markets in 2015. QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) sampling method was used in order to determine the pesticide’s residue in the pistachio nuts by Gas chromatography/Mass spectrometry (GC/MS).The method was validated with related parameters. Recovery took place at five concentration rates (n=3) ranging from 81.40% to 93.08% with the majority of RelativeStandard Deviation being lower than 20%. Limits of detection and quantification for all the pesticides were 2µg/kg and10µg/kg, respectively. The validated method seemed to be appropriate for the analysis of pesticide’s residue in pistachio nuts. Results: Identified pesticides included Fenitrothion, Carbaryl and Diazinon. Detectable pesticide’s residue existed in 10% (5 samples) of the samples. Conclusion: All the results were compared with the Iran’s National Standards and the European Maximum Residue Limits. As compared to the acceptable daily intake, the calculated daily intake of each pesticide was much lower than the standard level, which could not cause any public health problem

Additional file 1: of An optimized SPE-LC-MS/MS method for antibiotics residue analysis in ground, surface and treated water samples by response surface methodology- central composite design

It was provided in a format of DOC (Microsoft Word) including Central composite arrangement and responses in Table S.1 and ANOVA Tables S.2-10, The quadratic polynomial models and statistical parameters in Table S.11, Five proposed models for analysis of investigated antibiotics by multiresidues method in Table S.12, d iagnostic plots for ER% of amoxicillin in Fig.S.1, diagnostic plots for ER% of penicillin in Fig.S.2 and the chromatograms for MRM by the Zorbax-eclipse XDB-C18 column in Fig.S.3 were depicted. (DOCX 6167 kb