Chu Pham Ngoc Son*, Pham Thi Anh*, Nguyen Thi Van Hai** and Chu Van Hai*

*Centre of Analytical Services and Experimentation, HoChiMinh City
**School of Pedagogy, Cantho

Dexamethasone, a glucocorticosteroid and its derivatives, dexamethasone acetate, dexamethasone sodium phosphate are illegally added by farmers to feedstuffs or even directly given to domestic animals in order to get more profit with a faked increase in weight due to water retention. The consequence is the presence in pork, beef, chicken meat of these chemicals, which go therefore into the food chain and by accumulation may cause disturbance in the reciprocal function of hormone production between the suprarenal gland and the hypophysis. It is necessary to monitor this glucocorticoid and its derivatives in animal feedstuff as well as in meat for human consumption.

A method of unequivocal confirmation of dexamethasone by LC/MS/MS and a protocol of quantitative analysis combining appropriate extraction and enrichment was proposed, using a solid phase extraction technique followed by reversed phase HPLC quantitation, with high recovery (85%), high reproducibility and selectivity [1,2].

Food contamination with these glucocorticosteroids has been investigated by the Centre of Analytical Services and Experimentation (CASE) since 1998. Analytical results during the years 1999-2001 show that contamination of pork, beef, chicken meat and deliberate addition of dexamethasone and its derivatives to animal feedstuff although substantially decreased from year to year should still be a concern to VietNamese authorities. Thirty percent of the food samples analyzed at CASE during the year 2001 still show levels of contamination higher than the MRL of 0.5 ppb in meat and 2.5 ppb in liver, according to the 1998 decision of the Ministry of Health of VietNam.

REFERENCES
1. NGUYEN THI VAN HAI, PHAM THI ANH and CHU PHAM NGOC SON, Proceedings of the 1st Scientific and Technological Conference in Organic Chemistry, 256-258, September 9-11, 1999, Quinhon, VietNam
2. CHU PHAM NGOC SON, PHAM THI ANH, CHU VAN HAI, NGUYEN LAM KIEU DIEM and NGUYEN THI VAN HAI , Proceedings of the 1st National Conference on Analytical Sciences; September 26, 2000, Hanoi, VietNam.

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