Behaviour of some organophosphorus pesticide residues in thyme and stinging nettle tea during infusion process

Abstract

In order to investigate dissipation behaviour of fenitrothion, dimethoate, chlorpyrifos and pirimiphos-ethyl during infusion process, pesticide-free dried thyme and stinging nettle leaves were spiked with the pesticides. Infusions were prepared according to the usual process of infusion preparation. The effect of infusion process on the transfer of the pesticides from the spiked herbs leaves into brew was examined at intervals of 5, 10, 15 and 20 min. Residues were determined using gas chromatograph equipped with a flame ionization detector. The decrease in pesticide levels during infusion was found to be statistically significant (P < 0.05). Transfer of residues decreased considerably with infusion time. The carryover of the residues of dimethoate, which has the highest water solubility, into the infusions was the greatest. Satisfactory relationships were found between water solubility (W s ) and partition coefficient (K ow ) of the pesticides with the transfer of pesticides to brewed teas.

Transfer of difenoconazole and azoxystrobin residues from chrysanthemum flower tea to its infusion

“…Furthermore, the total content of the residues in infusions and spent chrysanthemum samples showed there was no loss of difenoconazole and azoxystrobin residues, indicating that the water temperature did not affect the volatilisation of the two compounds. The data also revealed there were different performances of the two analytes compared with the reduction of some OPP residues in thyme, stinging nettle (Ozbey & Uygun 2007a) and peppermint tea (Ozbey & Uygun 2007b). This may be in relation to the low volatilisation of difenoconazole and azoxystrobin, which in turn is controlled by Henry's law constants (H).…”

“…4, 666-675, http://dx.doi.org/10.1080/19440049.2014 infusions (Lin et al 2005;Lin & Zhu 2006). In the case of Chinese herbal medicines, the behaviour of five OPPs in peppermint, thyme and stinging nettle tea during 5-20 min of infusion was investigated (Ozbey & Uygun 2007a, 2007b. Another publication has concentrated on the degree of transfer of 11 OCP, OPP, azole, quinazoline and pyrethroid residues from herbal substrates to their respective herbal medicines (Tewary et al 2004).…”

Degradation kinetics of seven organophosphorus pesticides in milk during yoghurt processing

“…6,7 Uygun and Senoz studied the degradation of five organophosphorus pesticides in wheat during storage. In addition, the chemical nature of the pesticides and some factors, such as pH, light, metal ions and ozone, also impact the degradation of pesticide residues.…”

Validation of New Multi-Residue Method for the Determination of Organophosphorus Insecticides in Chrysanthemum Flower by Capillary Gas Chromatography

“…However, pesticides are often used in order to improve productivity and profit margins in the production of Chinese medicinal materials. The published researches on pesticide residues in crude herbal materials indicate that the presence of organophosphorus pesticide (OPP) residues is quite common (Ozbey and Uygun 2007;Vidal et al 2002;Garrido-Frenich et al 2003). Hence pesticide residues in Chinese medicinal materials become pitfalls in safety and present obstacles to be acknowledged by the international community (Qing et al 2009).…”