DETERMINATION OF METAL CONTAMINATION IN FRUIT JUICES IN TURKEY WITH METHOD VALIDATION AND UNCERTAINTY CALCULATION

9th Aegean Analytical Chemistry Days AACD 2014, Chios, Yunanistan, 29 Eylül - 03 Ekim 2014

The consumption rate of fruit juices have rapidly increased in the past years. Some elements

play an important role in the human diet to maintain normal physiological functions (Goldhaber,

2003). However, some elements like Ag, As, Be, Bi, Cd, Co, Pb and V do not occur naturally in

the body and they impose toxic effects when the share of the relevant beverages in the total diet

is high (Tahvonen, 1998). ICP-MS is sensitive multi-element technique to apply for fruit juice

samples after microwave digestion. The concentrations of Ag, As, Be, Bi, Cd, Co, Pb, Se and V

were determined in 42 commercial fruit juice samples. The orange and peach juices were mixed

to have a matrix for the method development and the validation studies. The samples were

digested with nitric acid and hydrogen peroxide in a microwave oven. The calibration was

accomplished by adding the standards prepared in the concentrations of 0.5, 1, 2, 5, 10, 25 and

50 µg L−1

from the 10 mg L−1

stock standard solution on the matrix. The method detection limits

for all elements investigated were found in the range of 0.02 and 0.14 µg L−1

. In order to verify

the recovery of the proposed method, standard reference material was used. The percent

recovery values changed between 83% (Be) and 118% (As). The average precision values for

all elements were determined as RSD (%) in the range of 1.3% and 2.9%. The main factors that

affect the results of the elements were the concentrations that were obtained from the calibration

curve, dilution factor, recovery and repeatability. Applying the bottom-up method, it was found

that the main contributions to the combined uncertainty came from the calibration curve and the

method recovery. The concentrations of all metals did not exceed the international and Turkish

Codex values.

KEYWORDS: Fruit juices, heavy metals, contamination, ICP-MS, method validation,