estimated in triplicate using atomic absorption spectrophotometer
(Perkin-Elmer 3110; Perkin Elmer, Waltham, MA). The operating
parameters for working these elements were set as per the
manufacturer’s protocol. Four external standard curves were
constructed using reference standard to quantify the metals
content in all samples. Calibration curves were performed with
5–6 different concentrations. For elemental analyses, a 10 cm
1-slot burner head with standard air-acetylene flame and single
element hollow cathode lamps were employed. A spoiler nebulizer
was applied for all the elements and for the Mg determination
impact bead nebulizer was used. IUPAC criteria were followed to
calculate the detection limit (Long & Winefordner, 1983)