摘要 |
An indicator compn. comprises (a) a tetrazole salt pref. of formula: where R1 is phenyl, naphthyl, p-iodophenyl or 3-methoxyphenyl; R2 and R3 are H or NO2; n is 1 or 2 (when n = 2, the two halves of the molecule are identical and when n = 1, R1 is linked to H), and (b) a PH 12-12.5 buffer. A prefd. indicator is neotetrazolium chloride. |