Monitoring of some pesticides residue in consumed tea in Tehran market

Abstract

Tea is an agricultural product of the leaves, leaf buds, and internodes of various cultivars and sub-varieties of the Camellia sinensis plant, processed and vulcanized using various methods. Tea is a main beverage in Iranian food basket so should be free from toxic elements such as pesticides residue. There is no data bank on the residue of pesticides in the consumed black tea in Iran. The present study is the first attempt for monitoring of 25 pesticide residues from different chemical groups in tea samples obtained from local markets in Tehran, I.R. Iran during the period 2011. A reliable and accurate method based on spiked calibration curve and QuEChERS sample preparation was developed for determination of pesticide residues in tea by gas chromatography–mass spectrometry (GC/MS). The using of spiked calibration standards for constructing the calibration curve substantially reduced adverse matrix-related effects and negative recovery affected by GCB on pesticides. The recovery of pesticides at 3 concentration levels (n = 3) was in range of 81.4 - 99.4%. The method was proved to be repeatable with RSDr lower than 20%. The limits of quantification for all pesticides were ≤20 ng/g. 53 samples from 17 imported and manufactured brand were analyzed. Detectable pesticides residues were found in 28.3% (15 samples) of the samples. All of the positive samples were contaminated with unregulated pesticides (Endosulfan Sulfate or Bifenthrin) which are established by ISIRI. None of the samples had contamination higher than maximum residue limit set by EU and India.

An Applicable Strategy for Improvement Recovery in Simultaneous Analysis of 20 Pesticides Residue in Tea

“…They also indicate that fortified calibration curves along with the proper solvent choice for extraction are approaches for elimination of false‐negative data caused by GCB in pesticide residue analysis. In the related study that is done in the laboratory, 53 black tea samples were collected from the Tehran market and analyzed for 25 pesticide residues with the method described here (Amirahmadi and others ). Detectable pesticides residues were found in 28.3% (15 samples) of the samples.…”

Simultaneous Analysis of Seven Non-authorized Pesticides Residue in Cucumber Using Spiked Calibration Curve by GC/ECD

“…Multi residue analysis of pesticides in food samples is one of the most important procedures in food control authorities [15,16]. There are references methods for simultaneous analysis, but the key point is how to match the food matrix with the selected method and with interested pesticides.…”

Evaluation of α- and β-Endosulfan Residues in Teas and Yerba Mate Infusions by Bar Adsorptive Microextraction and Large Volume Injection-Gas Chromatography Mass Spectrometry

“…According to the data, the proposed methodology presents recovery, LODs and LOQs in the same order of magnitude of currently sample preparation techniques, such as SPE, SPME, magnetic nanoparticles extraction (MNP), dynamic hollow fiber protected liquid phase microextraction (DHFP-LPME) and quick, easy, cheap, effective, robust and safe method (QuEChERS), even when they were combined with gas chromatography with electron capture detector (GC-ECD), two-dimensional gas chromatography (GC×GC) and tandem mass spectrometry (MS/MS) systems. 6,22,23,[26][27][28] Furthermore, the reduced costs associated, labor intensity and time effectiveness (in spite of long extraction time), are fairly better when compared with other approaches (e.g., SPE, SPME). The developed method is an alternative to current extraction methods, with comparable LOD and LOQ, and satisfactory recovery for trace analysis of α and β-endosulfan in tea and yerba mate samples.…”