Determination of the of pyridaben residues in strawberry fruit using gas chromatography- electron capture detector method

Considering the wide use of pyridaben acaricide in straw berry green houses, this study was carried out in research site of Islamic Azad University-Isfahan branch (2011-2012) to determine residues amount of pyridaben in straw berry fruits using gas chromatography-electron capture detector method. Study was done as factorial in a completely randomized design with three replications and two factors (poison amount with two levels and harvesting time after spraying with two and nine levels). After extracting the samples with dichloromethane, the extract was Purified using silica gel column and activated carbon and then acaricide residues were identified and determined using as chromatography-electron capture detector method. The recovery rate of acaricide was 98-102% in this method and detection limit of machine was micro gram per kilogram. Results showed that the highest concentration of acaricide in usual dose (0.4 lit/ha) was observed four hours after spraying in all replications and for twice the recommended dose (0.8 lit/ha) was related to 24 hours after spraying. According to results, the authorized amount of acaricide for exports to Europe Union (0.2 mg/kg) was obtained seven days after spraying for recommended dose and 21 days after spraying for twice dose. Also, a refrigerator experiment was carried out for testing the effects of cold on pyridaben residues. Results of this test showed that residues were more in twice the recommended dose (1.36 and 0.43 mg/kg for twice dose and recommended dose, respectively.) On the whole, the method was successful to determine residues amount of pyridaben acaricide and accurate and reliable results were included.

Keywords:

strawberry , pyridaben , acaricide , poison , residues , electron capture detector