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合成了新显色剂3-(4-硝基-2-3膦酸基苯偶氮)-6-(3-乙酰基苯偶氮)-4,5-二羟基-2,7-萘二磺酸(简称偶氮硝膦-mA或NP-mA)。该显色剂在草酸体系中能用于钇组稀土存在下对微量铈组稀土进行分光光度测定。方法在水溶液中进行测定,无需分离。 NP-mA能在强酸介质中与轻稀土瞬时形成络合物,试剂和络合物均稳定。试剂与络合物最大吸收分别在540nm与660nm。显色反应灵敏度高(ε_(660)~(ce)=7.5×10~4l·mol~(-1)·cm~(-1);Sandell灵敏度为0.0019μg·cm~(-2))且具有优良的选择性,各种合金元素包括常见离子的允许量大大超过其它同类试剂。比尔定律范围为0～15μg铈/25ml。对球铁及含Mn、Al、Cr较多的合金钢样品进行直接测定轻稀土含量,取得满意结果。
A new chromogenic reagent 3- (4-nitro-2-phosphonophenylazo) -6- (3-acetylphenylazo) -4,5-dihydroxy-2,7- Sulfonic acid (abbreviated as Azo Nitroso-mA or NP-mA). The developer can be used in oxalate system for rare earth cerium group in the presence of rare earth yttrium group spectrophotometry. The method is carried out in aqueous solution without isolation. NP-mA transiently forms complexes with light rare earths in strong acid media, stabilizing both reagents and complexes. Reagents and complexes maximum absorption at 540nm and 660nm. The sensitivity of the color reaction was high (ε_ (660) ~ (ce) = 7.5 × 10 ~ 4l · mol -1 · cm -1; the sensitivity of Sandell was 0.0019μg · cm -2) Excellent selectivity, a variety of alloying elements, including the allowable amount of common ions much more than other similar reagents. Beer’s law range 0 ~ 15μg cerium / 25ml. On the ductile iron and alloy steel containing Mn, Al, Cr more direct determination of light rare earth content, and achieved satisfactory results.