Agnihotri Nivedita, Kamal Raj, Mehta Jaswant R
Department of Chemistry, Kurukshetra University, Haryana, India.
Ann Chim. 2006 Jul-Aug;96(7-8):479-85. doi: 10.1002/adic.200690048.
3-Hydroxy-2-[1'-phenyl-3'-(p-chlorophenyl)-4'-pyrazolyl]-4-oxo-4H-1benzopyran (HPCPB) is used as an analytical reagent for the spectrophotometric determination of niobium in trace amounts with which it forms a yellow coloured complex (4:1) in perchloric acid medium. The complex is extractable into chloroform and shows absorption maximum at 407-418 nm with a molar absorptivity of 2.79 x 10(4) L mol(-1) cm(-1) and Sandell's sensitivity equal to 0.0033 microg Nb(V) cm(-2), respectively. Beer's law holds good in the range 0-1.2 microg Nb ml(-1), with a standard deviation of +/- 0.0015 absorbance units. The method is free from the interference of a large number of elements and handles satisfactorily the analysis of various samples of varying complexity.
3-羟基-2-[1'-苯基-3'-(对氯苯基)-4'-吡唑基]-4-氧代-4H-1-苯并吡喃（HPCPB）用作分光光度法测定痕量铌的分析试剂，它在高氯酸介质中与铌形成黄色络合物（4:1）。该络合物可萃取到氯仿中，在407 - 418 nm处有最大吸收，摩尔吸光系数为2.79×10(4) L mol(-1) cm(-1)，桑德尔灵敏度分别为0.0033 μg Nb(V) cm(-2)。比尔定律在0 - 1.2 μg Nb ml(-1)范围内成立，标准偏差为±0.0015吸光度单位。该方法不受大量元素的干扰，能令人满意地处理各种复杂程度不同的样品分析。
