Gas chromatographic determination of organochlorine pesticides in cow milk

Abstract

A gas chromatographic method of use in determining the following organochlorine pesticides in cow milk has been adapted and validated: alpha-hexachlorocyclohexane (alpha-HCH), beta-HCH, lindane, delta-HCH, hexachlorobenzene, aldrin, heptachlor, heptachlor epoxide, mirex, 2,4-dichlorodiphenyltrichloroethane (2,4-DDT), 4,4-DDT, 2,4-dichlorodiphenyldichloroethane (2,4-DDD), 4,4-DDD, 2,4-dichlorodiphenylethane (2,4-DDE) and 4,4-DDE. The method studied consists of three steps: the extraction of fat by centrifugation, mixing with anhydrous sodium sulfate, and transfer to a glass column and elution with hexane; purification of the extract via concentrated sulfuric acid treatment; and determination of the organochlorine pesticides by gas chromatography equipped with an electron capture detector. The analytical parameters determined to estimate the quality of the method yielded the following results: correlation coefficients (r) of the calibration curves were greater than 0.996, the variation coefficients of the response factors were less than 4.90%--with the exception of aldrin (5.53%) and lindane (5.75%)--the relative standard deviation of the slope (Sm rel) being < or =1.52%. Zero was included in the confidence limits of the independent term range. The method repeatability and reproducibility values were < or =4.73% and < or =5.79%, respectively. The recovery values of the pesticides analyzed were in the range of 81.92% (alpha-HCH) to 105.49% (4,4-DDT), except in the case of aldrin and heptachlor epoxide, which yielded recovery values of under 40%. The quantification limits of the method were < or =1 ng/g, with the exception of mirex (5 ng/g).

Uterotrophic effects of cow milk in immature ovariectomized Sprague–Dawley rats

“…As such, they are consistent with those of Ganmaa et al's study where a mixture denoted ''artificial milk'' was used to mimic commercial milk [21]. Although protein, fat, and carbohydrate were present in this artificial milk at typical levels, the concentrations of minerals and contaminants were significantly different from those of real milk [10,22]. The main improvement of the study reported here is the use of traditional milk.…”

“…Most studies on milk have identified beneficial effects, such as the prevention of osteoporosis and the promotion of growth and development. However, milk also contains organochlorine pesticides and endogenetic estrogens, which are classified as EDCs [10]. Forty years ago, Armstrong and Doll reported an association between the intake of milk-based products and increased breast cancer mortality [11].…”