Store samples at laboratory to prevent degradation and loss of volatiles, if appropriate(e.g. chili at about 4 C or freeze).
Dry sampie to constant weight and preventing fusing of sample(e.g. oven dry 40-105°C or freeze X dry). (May need to analyse wet for r. volatile radionuclides)
Record We ratio
Remove gravel component by sieving to 2 mm and discarding >2 mm fraction.
Ensure representative sub- sample is taken for analysis(for example, by grinding and coning and quartering).