Grassi Viviane, Dias Ana Cristi B, Zagatto Elias A G
Centro de Energia Nuclear na Agricultura, Universidade de São Paulo, P.O. Box 96, Piracicaba SP 13400-970, Brazil.
Talanta. 2004 Dec 15;64(5):1114-8. doi: 10.1016/j.talanta.2004.04.037.
An expert sequential injection system involving a prior assay is proposed for spectrophotometric determination of phosphate and eventually zinc in soil extracts. The result of phosphate determination is the basis for a concentration-oriented decision regarding to the need or not for zinc determination. Zinc was only determined if a threshold value (peak height corresponding to 5.0mgl(-1)P) was surpassed. The methods involved formation of molybdenum blue and the Rhodamine 6G/ammonium thiocyanate/Zn(2+) ternary complex. Variations in the threshold value were < 2% during 4h operating periods, false responses were not verified, and the analytical time was reduced in about 30%. Precise results (R.S.D. <3%P and < 1% Zn) in agreement with spectrophotometry and flame atomic absorption spectrometry were obtained. The innovation permits faster information processing, as well as a reduction in the number of measurements, number of analytical steps, laboratorial time, and consumption of sample and reagents, thus waste generation.
本文提出了一种涉及先前分析的专家顺序注射系统，用于分光光度法测定土壤提取物中的磷酸盐以及最终的锌。磷酸盐测定结果是决定是否需要测定锌的浓度导向决策的依据。只有当超过阈值（对应于5.0mg L⁻¹磷的峰高）时才测定锌。该方法涉及钼蓝和罗丹明6G/硫氰酸铵/锌（Ⅱ）三元配合物的形成。在4小时的操作期间，阈值变化小于2%，未验证到错误响应，分析时间减少了约30%。获得了与分光光度法和火焰原子吸收光谱法一致的精确结果（相对标准偏差<3%磷和<1%锌）。该创新允许更快地处理信息，以及减少测量次数、分析步骤数、实验室时间以及样品和试剂的消耗，从而减少废物产生。
