title: Assessment of toxic metals in raw and processed milk samples using electrothermal atomic absorption spectrophotometer.
abstract: Milk and dairy products have been recognized all over the world for their beneficial influence on human health. The levels of toxic metals (TMs) are an important component of safety and quality of milk. A simple and efficient microwave assisted extraction (MAE) method has been developed for the determination of TMs (Al, Cd, Ni and Pb), in raw and processed milk samples. A Plackett-Burman experimental design and 2(3)+star central composite design, were applied in order to determine the optimum conditions for MAE. Concentrations of TMs were measured by electrothermal atomic absorption spectrometry. The accuracy of the optimized procedure was evaluated by standard addition method and conventional wet acid digestion method (CDM), for comparative purpose. No significant differences were observed (P>0.05), when comparing the values obtained by the proposed MAE method and CDM (paired t-test). The average relative standard deviation of the MAE method varied between 4.3% and 7.6% based on analyte (n=6). The proposed method was successfully applied for the determination of understudy TMs in milk samples. The results of raw and processed milk indicated that environmental conditions and manufacturing processes play a key role in the distribution of toxic metals in raw and processed milk.
authors.affiliation: National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, Sindh, Pakistan. tgkazi@yahoo.com
authors.forename: Tasneem Gul
authors.initials: TG
authors.lastname: Kazi
authors.forename: Nusrat
authors.initials: N
authors.lastname: Jalbani
authors.forename: Jameel Ahmed
authors.initials: JA
authors.lastname: Baig
authors.forename: Ghulam Abbas
authors.initials: GA
authors.lastname: Kandhro
authors.forename: Hassan Imran
authors.initials: HI
authors.lastname: Afridi
authors.forename: Mohammad Balal
authors.initials: MB
authors.lastname: Arain
authors.forename: Mohammad Khan
authors.initials: MK
authors.lastname: Jamali
authors.forename: Abdul Qadir
authors.initials: AQ
authors.lastname: Shah
mesh_terms: D000535:Aluminum / Q000032:analysis*; D000818:Animals; D002104:Cadmium / Q000032:analysis; D002417:Cattle; D004784:Environmental Monitoring / Q000379:methods; D004785:Environmental Pollutants / Q000032:analysis*; D005506:Food Contamination / Q000032:analysis*; D007854:Lead / Q000032:analysis; D019216:Metals, Heavy / Q000032:analysis*; D008892:Milk / Q000737:chemistry*; D009532:Nickel / Q000032:analysis; D013054:Spectrophotometry, Atomic / Q000379:methods*
chemical_list: D004785:Environmental Pollutants; D019216:Metals, Heavy; D002104:Cadmium; D007854:Lead; D009532:Nickel; D000535:Aluminum