| dc.description.abstract | 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 70oC
for 10 hours. | en |
