Levels of cadmium, lead, copper and zinc in some vegetables by flame atomic absorption spectrophotometry

Date

1999

Degree

Bachelor of Science in Agricultural Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Maxima E. Flavier

Abstract

Copper, zinc, lead and cadmium of ampalaya, okra, pechay, repolyo and talong were analyzed by flame atomic absorption spectrophotometry (FAAS). Two methods for sample preparation were compared namely wet digestion method using different acid mixtures (HNO3/H2O2, HNO3/H2SO4 and HNO;/HCIOa) and dry ashing method maintained at various temperatures (450℃, 550℃ and 650℃). In the wet digestion procedure, the concentrations of Cu, Zn, Pb and Cd were significantly different among the vegetables depending on the acid combination used in the sample preparation. Results for the HNO3/H2SO4 and HNO3/HCIO4 acid combinations were significantly different compared to HNO3/H2O2 In the dry ashing method three ashing temperatures were compared; 450℃, 550℃ and 650℃. Results showed that the efficiency of the dry ashing method depends on the type of metal to be analyzed. Ashing temperature at 650℃ was efficient for the detection of Cu and Zn, 550℃ for Cd and Pb. Percentage recoveries using secondary reference material such as QAC 119 Seafood Mix and QAC 141 Mutton Liver were determined in order to assess the accuracy of the two methods. The highest percentage recoveries were observed for Cu(82.15%). Zn(136.00%), Pb(93.87%) and Cd(87.97%) using HNO3/HCIO4 acid combination. Lower recoveries were obtained for the dry ashing method. The detection limits for Cu. Zn, Pb and Cd were 0.0582 mg/kg. 0.0543 mg/kg, 0.0437 mg/kg and 0.0031 mg/kg. respectively. Generally the wet digestion procedure was the more appropriate method for the sample preparation in the determination of trace metals in vegetables The concentration levels of copper, zinc, lead and cadmium in the five kinds of vegetables obtained from Quiapo public market did not exceed the maximum metal concentration set for vegetables.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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