6 November

Today was the turn of the anion concentrations in the water samples to be measured, this was done at the geography department at the University of Durham. Anions are measured by ion chromatography, the water samples pass through a column and beacuse each ion has a different size and charge the anions move at different speeds and get separated out. For each sample the result is a set of peaks and the concentrations are proportional to the area under each peak. Each sample takes abour half an hour to run but luckily there is an autosampler which takes 100 samples so it is just a case of loading everything up and letting the machine do the rest.