Determination of the concentrations of trace elements in a variety of drinking juices

Abstract

Drinking juices (n=90) were sampled from Nairobi, Nyeri, Naivasha and Ruin, where microscale industries are well established with the aim of determining the levels of trace elements. Juices from Nairobi macro-scale industries were also sampled for comparison purposes. Elemental concentrations were done using Energy Dispersive X-ray Fluorescence (EDXRF) technique after digestion of the samples. The highest elemental concentrations detected were; manganese, 143 ± 12 ug r', in Frenah from Nairobi micro-scale industries, iron, 2070 ± 293 ug r', in canned PEP Orange from Nairobi macro-scale industries, copper, 306 ± 7 ug r', in canned PEP Orange from Nairobi macro-scale industries, zinc, 1762 ± 95 ug r', in mumpop Orange from Nairobi micro-scale industries and lead, 156 ± 60 ug r', in TruFru Pineapple drink from Nairobi macro-scale industries. There was a notable variation of elemental concentrations within the brands and also a positive correlation between most of the elements. However a negative correlation of zinc and manganese was realized among samples from Ruiru. The research also aimed at studying the trend of elemental concentrations with shelf life for plastic packaged and canned juices. It was observed that the concentration of iron increased significantly with shelf life for canned juices while for plastic packed juices there were no significant changes noted. The elemental concentrations for manganese, iron, copper and zinc from all sampling regions were found to be below maximum guidelines recommended by the Kenya Bureau of Standards (KEBS) and the World Health Organization (WHO). Lead was detected in some brands although not at alarming levels.