The efficiency of various household processing for removing chlorpyrifos and cypermethrin in Chinese kale and Pakchoi

The vegetables, Chinese kale and Pakchoi, which are popular among the Thai people, are found to have problems with residues of pesticide. The pesticide residues in both Kale and Pakchoi were chlorpyrifos and cypermethrin. This research was to study the efficiency of pesticide residue reduction in Chinese kale and Pakchoi samples by using various household wash processing. The process included washing with normal water, 0.10% NaCl, baking soda, water flowing, and blanching. Pesticide residues were extracted from Chinese kale and Pakchoi to determine the amount of chlorpyriphos and cypermethrin residue by using analytical tools such as Gas Chromatography— Flame Photometric Detector (FPD) and Gas Chromatography—Electron Capture Detector (ECD). The results showed that the household processes for reducing the chlorpyrifos residue in Chinese kale and Pakchoi were the following: residues were reduced by 52.70–65.41%, 58.33–62.14%, 59.46–80.52%, and 46.04–62.85% when washed with normal water, 0.10% NaCl, baking soda, and water flowing through, respectively. Similarly, the household processes for reducing cypermethrin residue in Chinese kale and Pakchoi were the following: residues were reduced by 51.13–66.29%, 33.75–45.65%, 38.14–63.64%, and 44.88–61.63% when washed with normal water, 10% NaCl, baking soda, and water flowing through, respectively. Also, blanching reduced the chlorpyrifos residue by 37.96–50.44% and the cypermethrin residue by 47.86–52.42%. Therefore, while washing vegetables by soaking and dissolving substances, baking soda is the most effective when used for washing for at least 15 min to reduce the residue of pesticides. The consumers should be provided vegetables that are cleaned and have had a proper washing for removing pesticide residues and toxic residues.

Determination of Organophosphorus Pesticide Residues in Winter Bamboo Shoots by Homogenate Extraction Coupled with Gas Chromatography-Flame Photometric Detector

Excessive use of organophosphorus pesticides (OPPs) in fruits and vegetables may affect human health. In this paper, a simple, rapid and effective method for the determination of five OPPs in winter bamboo shoots by gas chromatography-flame photometric detector (GC-FPD) was developed. Three extractants and three extraction methods were examined respectively. The results showed that the recovery rate was higher when the samples were extracted by acetonitrile and treated with homogenate extraction method. Under the optimized conditions, recoveries ranged from 82.12% to 91.48% with the relative standard deviation (RSD) of 1.51-4.20% and the limit of detection (LOD) of 0.005-0.02 μg/mL. Results showed that using acetonitrile as extractants and homogenate extraction in sample preparation is an effective method in determination of pesticide residues in winter bamboo shoots.

Analysis of sulfur compounds using a water stationary phase in gas chromatography with flame photometric detection

The properties of using a water stationary phase for analyzing organic sulfur compounds in capillary gas chromatography (GC) with a flame photometric detector (FPD) are presented.