Validation of an analytical method for determination of 13 priority polycyclic aromatic hydrocarbons in mineral water using dispersive liquid-liquid microextraction and GC-MS

Dispersive liquid-liquid microextraction [DLLME] combined with gas chromatography-mass spectrometry [GC-MS] was used for the extraction and determination of 13 polycyclic aromatic hydrocarbons [PAHs] in mineral water samples. In this procedure, the suitable combination of extraction solvent [500 microL chloroform] and disperser solvent [1000 microL acetone] were quickly injected into the water sample [10.00 mL] by Hamilton syringe. After centrifugation, 500 microL of the lower organic phase was dried under a gentle stream of nitrogen, re-dissolved in chloroform and injected into GC-MS. Chloroform and acetone were found to be the best extraction and disperser solvent, respectively. Validation of the method was performed using spiked calibration curves. The enrichment factor ranged from 93 to 129 and the recovery ranged from 71 to 90%. The linear ranges for all the PAHs were 0.10-2.80 ngmL-1. The relative standard deviations [RSDs] of PAHs in water by using anthracene-d[10] as internal standard, were in the range of 4-11% for most of the analytes [n=3]. Limit of detection [LOD] for different PAHs were between 0.03 and 0.1 ngmL-1. The method was successfully applied to the analyze of PAHs in mineral water samples collected from Tehran

Evaluation of emerging Fusarium mycotoxins beauvericin, Enniatins, Fusaproliferin and Moniliformin in domestic rice in Iran

The occurrence of emerging Fusarium mycotoxins beauvericin [BEA], enniatins [ENNs] [A, A1, B, B1], Fusaproliferin and moniliformin was evaluated by a liquid chromatography/ electrospray ionization-tandem mass spectrometric [LC/ESI-MS/MS] technique in 65 domestic rice samples produced in Gilan and Mazandaran Provinces in Iran. The results showed that 46% of the samples were contaminated with at least one of the emerging mycotoxins. BEA was the most prevalent mycotoxin, which was found in 26 out of 65 rice samples at the concentrations up to 0.47 microg/Kg. Enniatin A1 which was the only member of ENNs was detected in the samples, occurred in 7.7% of samples with an average level of 0.06 microg/Kg. No detectable level of Fusaproliferin and moniliformin was found. This is the first report concerning the contamination of Iranian domestic rice samples with the emerging Fusarium mycotoxins

Occurrence of deoxynivalenol in foods for human consumption from Tehran, Iran

The occurrence of deoxynivalenol [DON] in retail foods in Tehran [Iran] was determined using high-performance liquid chromatography technique and immunoaffinity column as the clean-up step. A method was validated for analysis of DON in rice, bread, puffed corn snack and wheat flour. The average recoveries and precision [RSD] for DON in different foods ranged 84.2-93.1% and 2.9-12.0%, respectively. A survey of DON was performed on the 72 samples of rice, bread, puffed corn snack, and wheat flour collected from Tehran retail market. The data showed that 10 samples [13.9%] out of 72 samples were contaminated with DON with the maximum level of 368.7 ng/g. The samples had contamination level lower than the maximum tolerated level of DON in foods in Iran. The total intake of DON was under the provisional maximum tolerable daily intake set for DON by the JECFA

Method development for simultaneous determination of 41 pesticides in rice using LC-MS/MS technique and its application for the analysis of 60 rice samples collected from Tehran market

For the first time, a multi-residue method for simultaneous determination of 41LC-amenable pesticides in rice, belonging to different chemical classes has been developed in Iran by LC-MS/MS. The pesticides were analyzed simultaneously in a single run using positive electrospray ionization with multiple reaction monitoring [MRM] after extraction with slightly modified QuEChERS method. The calibration curves for each analyte were linear in the concentration range 0.02-1.0 microg/g with a correlation coefficient range between 0.993 and 0.999. The LOQ and LOD were0.025 microg/g and 0.008 microg/g respectively, for all 41 pesticides and the mean recoveries obtained for three fortification levels [0.025, 0.08 and 0.250 microg/g ] were71-119% with satisfactory precision [RSD<20%]. The developed method was used to investigate the occurrence of pesticides in 30domestic and 30 imported rice samples collected from Tehran market. Five compounds were detected in 11 domestic and 9 imported positive samples in concentration range from 0.032 microg/g to 0.081 microg/g and 0.028 microg/g to 0.074microg/g, respectively. With the exception of prohibited pesticides, phosphmidon and TCMTB, three permitted pesticides, cinosulfuron, triadimenol and tricyclazole, found in positive rice samples were below MRLs established by Institute of Standards and Industrial Research of Iran [ISIRI]

Analysis of aflatoxin B1 in Iranian foods using HPLC and a monolithic column and estimation of its dietary intake

A high performance liquid chromatographic method was developed for determination of aflatoxin B1 [AFB1] in foods using a monolithic column with sample clean up on an immunoaffinity column. The method was validated for analysis of AFB1 in rice, bread, puffed corn snack, wheat flour and peanut samples. The average recoveries for AFB1 in different foods ranged from 94.4 to 102.5% with the coefficient of variation lower than 10% for all foods. Limit of detection was 0.01 ng/g. A survey of AFB1 was performed on 90 samples collected from Tehran retail market in June 2005. The results showed that none of the bread and wheat flour samples were contaminated with AFB1. The mean AFB1 levels in rice, puffed corn snack and peanut samples were 4.17, 0.11, and 1.97 ng/g, respectively. The level of contamination of 3 samples [one rice sample and two peanuts samples] to AFB1 was found to be higher than 5 ng/g. Although all food samples had mean concentration of AFB1 below the maximum tolerated level in Iran, the mean intake of AFB1 from rice was estimated 3.49 times higher than the guidance value of 1 ng AFB1/Kg body weight/day. Therefore, it is strongly recommended to monitor AFB1 in foods, especially in rice, in Iran. This is the first study on exposure assessment of Iranian population to AFB1

Simultaneous determination of 17 pesticide residues in rice by GC/MS using a direct sample introduction procedure and spiked calibration curves

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

Exposure assessment of the Tehran population [Iran] to zearalenone mycotoxin

Zearalenone [ZEA] mycotoxin is a potent estrogenic metabolite. It is the primary toxin causing infertility, abortion or other breeding problems. A HPLC method was validated for ZEA in foods using a monolithic column with sample clean-up on an immunoaffinity column. A certified reference material [CRM] from FAPAS [UK] was analyzed. A survey of ZEA was performed on the 72 samples of rice, bread, puffed corn snack and wheat flour collected from Tehran retail market. The average recovery and coefficient of variation in different foods ranged 92.7-107.1 and 4.9-13.8%, respectively. The amount of ZEA in corn CRM was in the acceptable range of FAPAS. The limit of quantification was 3 ng/g for rice, bread and wheat flour and 2.7 ng/g for puffed corn snack. The retention time of zearalenone was 2.6 min. All samples had contamination level lower than the maximum tolerated level of ZEA in foods in Iran. The mean intake of ZEA from all samples was much lower than the tolerable daily intake estimated by JECFA. This is the first survey on ZEA contamination in bread and rice in Iran as well as the first study on exposure assessment of Tehran population to ZEA

Natural occurrence of mycotoxins in cereals from Mazandaran and Golestan provinces

Bakground-Aflatoxins [AF] and ochratoxin A [OA] are two toxic substances produced by specific types of fungi. Many reports consider them as carcinogens and nephropathogens, respectively. Objective-The aim of this study was to present the natural occurrence of AF and OA in some important foodstuffs in the southern Caspian littoral. Methods-Fourteen barley and nine corn samples, intended for animal feed, were collected from Golestan and Mazandaran provinces, northern Iran, and were analyzed for AF and OA by high performance liquid chromatography [HPLC]. Results-In corn samples, aflatoxin B1 [AFB1] and aflatoxin B2 [AFB2] were detected in 8 [88.8%] and 6 [66.6%] samples at a mean level of 15.83 and 2.99 ppb [median 1.72 and 1 ppb] respectively. Only one of the AF-contaminated corn samples was co-contaminated with OA at a concentration of 0.35 ppb. Neither AF nor OA were found in any of the barley samples. Conclusion-This study was the first report on natural occurrence of OA and its co-occurrence with AF in the corn samples of northern Iran. Although our findings showed a low level of AF and OA, we recommend a periodical survey to be conducted on the natural occurrence of mycotoxins in cereals from the Caspian littoral