BackgroundPesticides are a reason for popular concern due to their possible unfavorable results on human safety. Most pesticide residues are present in food owing to the direct application of a pesticide to a crop. The aims of this study were; development a multiresidue method for analysis of 81 pesticides in tomato using GC/MS, and detection and quantitation of the studied pesticides in tomato samples gathered from various stores of Iran.MethodsThe pesticides were assessed concurrently in a single run applying GC/MS after extraction with QuEChERS method. Homogenized tomato samples were weighed into centrifuge tubes. The studied pesticides were extracted using acetonitrile, followed by the addition of a mixture of anhydrous magnesium sulfate and sodium acetate. In order to remove excess water and other components of tomato a combination of primary secondary amine and magnesium sulfate was applied, and then the extracted components were analyzed by GC-MS.ResultsThe calibration curves for all analytes were linear in the range of 20–200 ng/g with a determination coefficient (R2) in the range between 0.993 and 0.999. The LODs and LOQs were in the range between 2.5–6.7 and 7.5–20 ng/g respectively, and the mean recoveries obtained for three fortification levels (25,50 and 100 ng/g -five replicates each) were 72–116% with RSD < 20%. Six residues were found in 31 (20.7%) samples. Iprodione was the most common detected residues (6.0%), followed by permethrine (4.7%), esfenvalerate (4.7%), chlorpyrifos (3.3%), diazinon (2.0%), and penconazole (1.3%).ConclusionsAmong the detected pesticides, only Iprodione, permethrine, chlorpyrifos and diazinon are registered for tomato production in Iran. With exception of Chlorpyrifos and diazinon the concentrations of iprodione and permethrine were found below the maximum residue levels (MRLs) established by Iranian National Standard Organization (INSO). Esfenvalerate and penconazole are not registered for tomato production in Iran. Therefore, it is necessary to control and management of their residues in tomato.

Background: Organophosphorus pesticides are widely used in agriculture, homes, gardens, and

Melamine is an organic-based chemical material widely used in the production of tableware. Given the adverse effects of melamine on human health, melamine tableware can be a source for its introduction into the human body. The aim of this study was to use a simple method for monitoring the rate of melamine migration from the tableware to food and the effect of time and tableware on this migration. To measure the migration, spectrophotometry was used. The limit of detection (LOD) of the method was 0.2 (μg/ml), which is functional for measuring the rate of migration. The investigation of sample migration of melamine tableware revealed that migration has occurred across all samples. The rate of migration in all samples was less than the standard level of the European Union (30 μg/ml). Statistical analysis indicated that time is an important factor in melamine migration, which significantly increased (p<0.05) in 93% of cases with lengthening the contact time from 30 minutes to 90 minutes. The type of tableware (new or old) and production conditions (standard or non-standard) were found to significantly affect (p<0.001) the rate of migration. Statistical analysis of the results suggested that old tableware increased melamine migration in 41% of cases (p<0.05). Non-standard tableware significantly (p<0.001) increased the rate of migration and thus the effect of non-standard production on melamine tableware was more significant than the age of the tableware.

Melamine is an organic-based chemical usually found as enriched white nitrogen crystals. Since melamine is used for manufacturing food dishes and containers, there are concerns about melamine migration from the dishes into foods and subsequently the human body, particularly in children. As there are no routine techniques to measure melamine migration in food quality control laboratories in Iran, we here aimed to validate HPLC and spectrophotometry methods to measure migration of this substance. The HPLC and spectrophotometry techniques were adopted and validated. The level of melamine migration was measured in melamine ware of five brands in Iran market. Distilled water and acetic acid 3% were used as simulants. The dishes were in contact with the simulants for 90 min at 90 °C.The accuracy and precision were obtained as 94.9 and 95.3% for HPLC and 95.3% and 96.2% for spectrophotometry, respectively. Furthermore, the limit of detection (LOD) and limit of quantification (LOQ) were obtained as 145 and 435 ng/ml for HPLC, and 200 and 605 ng/ml for spectrophotometry, respectively. Our results indicated that HPLC can be a reliable method to measure low-level melamine. The spectrophotometry could also be applied as a feasible, accurate, and cost-effective method for measuring melamine in foodstuffs. This research has tried to adopt a method to measure melamine migration in the regions where there are no routine techniques to measure melamine migration the same as Iranian food laboratories. The validation results of HPLC and spectrophotometry methods showed 94.9% accuracy and 95.3% precision and 95.3 and 96.2% for spectrophotometry respectively which were reliable. HPLC can be a reliable method to measure low-level melamine. The spectrophotometry could also be applied as a feasible, accurate, and cost-effective method for measuring melamine in foodstuffs.