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Modification in direct analysis method: metal levels in raw milk at the region of Izmit by graphite furnace atomic absorption spectrophotometer
Author(s) -
Ay Ümit,
Karayünlü Seda
Publication year - 2008
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/j.1365-2621.2006.01441.x
Subject(s) - cadmium , atomic absorption spectroscopy , graphite furnace atomic absorption , chemistry , graphite , phosphoric acid , nuclear chemistry , matrix (chemical analysis) , certified reference materials , metal , analytical chemistry (journal) , chromatography , materials science , metallurgy , detection limit , physics , quantum mechanics
Summary A simple method was developed for the determination of cadmium (Cd) and lead (Pb) in milk serum prepared by spontaneous souring, using graphite furnace atomic absorption spectrophotometry. Samples of raw milk were collected from the bulk holding tanks of thirty‐six dairy farms in twelve localities in Izmit. The samples were kept at room temperature (25 °C) for 48 h in order to allow the pH to decrease below 4.6, and the casein and fat to precipitate. Milk serum was filtered and directly injected into a graphite tube. The standard addition method was employed, and 0.1% phosphoric acid was used as the matrix modifier. The mean recoveries from three added concentrations were 91.4% for Cd and 95.8% for Pb. Cadmium and Pb concentrations found in the reference standard milk powder using this method were close to the certified values. The mean Cd contents obtained from thirty‐six samples were 0.257 μ g L −1 , ranging from 0.180 to 0.398 μ g L −1 . The mean Pb contents found were 6.83 μ g L −1 , ranging from 5.32 to 9.94 μ g L −1 .