By Anonymous on Sunday, October 5, 2003 - 11:27 pm:
Hello at all,
I'm searching a method for analysing vamidothion (organophosphoric insecticide) with capillary gascromatography. The only I have found is an ancient method that involve oxidation of vamidothion with permanganate.
There is an alternative? Is possible to obtain a good chromatographic separation and MS detection with a simple modification in injection technique?
Any input is greatly appreciated
Thanks in advance.
By ralph on Thursday, October 9, 2003 - 08:33 am:
I found this reference which suggests that you can, if it is of any help:
SIMULTANEOUS DETERMINATION OF VAMIDOTHION AND ITS OXIDATION METABOLITES IN POTATOES AND APPLES BY GAS-CHROMATOGRAPHY
TSUMURA Y, MATSUKI H, TONOGAI Y, NAKAMURA Y, KATO S, ITO Y
JOURNAL OF FOOD PROTECTION
56 (5): 437-440 MAY 1993
Language: English
Abstract:
A method for simultaneous determination of vamidothion (V0) and its oxidation metabolites vamidothion sulphoxide (V1) and vamidothion sulphone (V2) in potatoes and apples has been developed. Fifty grams of a sample was homogenized and extracted with acetone followed by evaporation to remove the acetone. To the residual aqueous solution, a 10% sodium chloride solution was added, and the coextractives were eliminated by washing the aqueous solution with 10% ethyl acetate in hexane. Then, VO, VI, and V2 were extracted from the aqueous solution using dichlommethane. The organic layer was evaporated to dryness and filled up to 2 ml with ethyl acetate. Two microliters of the extract were injected into gas chromatograph-mass spectrometer set for selected ion monitoring. The column used was a CBP-1 capillary column (0.2 mm inside diameter x 15 m, 0.25 mum film thickness). Gas chromatographic conditions were investigated in detail and only nonpolar capillary columns gave satisfactory results. The retention time of undecomposed V1 has been reported for the first time. The recoveries for the fortified potatoes and apples were 93-109% for VO, 62-108% for VI, and 64-89% for V2, when they were fortified at levels of 0.01-5.0 ppm. Detection limits were 0.01, 0.2, and 0.05 ppm for V0, V1, and V2, respectively.
Regards,
Ralph
By Anonymous on Thursday, October 16, 2003 - 02:11 am:
Hi Ralph,
I have accessed today the forum after few days of vacancies.
Thank you very much.
Regards.