Determination of trace elements in mineral water samples using total reflection X ray fluorescence (TXRF)

Full text: Preliminary results of trace element analysis by TXRF of drinking tap water, various brands of local and imported bottled water samples sold in Nairobi as mineral are presented. The levels of potassium(K) ranged from 0.2 to 28.9 μg/ml, calcium(Ca) 2.2 to 120 μg/ml, titanium(Ti) 11 to 60 μg/l, manganese(Mn)8 to 670 μg/l, iron(Fe)31 to 50 μg/l, copper(Cu) 8 to 30 μg/l, bromine(Br) 9 to 248 μg/l, rubidium(Rb )10 to 40 μg/l, and strontium(Sr)10 to 1000 μg/l. It was found that the local mineral water samples contained higher levels of trace elements especially Mn, Zn, Br, Rb and Sr compared to the imported brands. Principal component analysis of the results revealed three factors with the highest component loadings clustering Rb, Sr, Ca in the first eigenvalue; Ti, Fe, Br, Zn, in the second; Zn, Mn, K in the third. A limited spread of 5-6 mm for a 10μl samples was achievable by completely drying the quartz Suprasil sample carrier in a low pressure (300mbar) oven at temperature of 70 deg. C for 10 hours. (author)