passages.id: split_5_test_1878_passage
passages.type: progene_text
passages.text: Thiamin ( vitamin B1 ) produced a well - defined wave in 0.1 M KCl at pH 5.2 with E(1/2 ) = - 1.2 V and E(p) = - 1.22 V versus saturated calomal electrode ( SCE ) .