PAN-S作为显色剂的研究

目前,一些性能优良的光度显色剂水溶性较差,一般需用有毒性的有机溶剂进行萃取光度测定。因此,改造老试剂,寻求可溶性的无毒新试剂对分析化学是有意义的。Ohshita等人^[1]通过2-氨基吡啶重氮化与β-萘酚磺酸偶联合成了1-(2-吡啶偶氮)-2-萘酚-磺酸(简称PAN-S),合成步骤繁琐,提纯困难,产率低。张孙玮等曾用PAN直接磺化来制备PAN-S,但由于磺化后用氢氧化钠处理,未能得到纯品。我们发现,将磺化后的溶液倾入适量的水中,就能析出PAN-S。该法具有制备简单、易得纯品、成本低等特点。本文报导PAN-S的制备和性质及其与金属离子的反应。

The Study of 1-(2-Pyridylazo)-2-Naphthol-Sulfonic Acid as a Spectrophotometric Reagent

1-(2-pyridylazo)-2-naphthol-sulfonic acid (PAN-S) was obtained simply and effectively by sulphonation of PAN.The acidity constant of the reagent is reported.The investigation of the reaction of PAN-Swith metal ions shows that the characteristic of PAN-Sas a spectrophotometric reagent is similar to that of PAN.The analytical procedure would be simpler and more convenient as PAN-Sis water-soluble.