Due to the prohibition on importing ClCN to Hong
Kong and to the short shelf-life of ClCN, standards of
ClCN for calibration curve establishment were freshly,
in situ developed by 30-min chlorination of glycine
solution (0.5 mgL1 as N) at a free chlorine dosage of
5mgL1 (as Cl2) and phosphate-buffered pH of 7.