Confirmatory identification of an unknown substance formed during sustained storage of Regain granules

A variety of analytical methods were applied to confirm the identity of a white powder sample from Cirrus Ag as either sodium sulphate or calcium sulphate. These included FTIR spectroscopy, solubility testing, measurement of water of crystallisation, and sodium and calcium quantification through atomic absorption spectroscopy. The results support the identification of the white powder as principally sodium sulphate (approx. 93% assay on a dry- weight basis). If present, calcium sulphate appears to be a minor constituent.