A novel and sensitive floatation-spectrophotometric method is presented for determination of trace amounts of thorium in water samples. The method is based on the ion-associated formation between thorium, Eriochrome cyanine R and Brij-35 at pH = 4 media. The complex was floated in the interface of the aqueous phase and n-hexane by vigorous shaking. After removing the aqueous phase the floated particles were dissolved in methanol and the absorbance was measured at 607 nm. The influence of different important parameters such as Eriochrome cyanine R and surfactants concentration, pH, volume of n-hexane, standing time and interfering ions were evaluated. Under optimized conditions the calibration graph was linear in the range of 6–230 ng mL−1 of thorium with a correlation coefficient of 0.9985. The limit of detections (LOD), based on signal to noise ratio (S/N) of 3 was 1.7 ng mL−1. The relative standard deviations for determination of 150 and 30 ng ml−1 of thorium were 3.26 and 4.41%, respectively (n = 10). The method showed a good linearity, recoveries, as well as some advantages such as sensitivity, simplicity, affordability and a high feasibility. The method was successfully applied to determine thorium in different water and urine samples.
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机译：提出了一种新颖灵敏的浮选光度法测定水样中痕量的or。该方法基于在pH = 4的介质中th，Eriochrome花青R和Brij-35之间的离子缔合。通过剧烈摇动将络合物漂浮在水相和正己烷的界面中。除去水相后，将漂浮的颗粒溶解在甲醇中，并在607nm处测量吸光度。评估了各种重要参数的影响，例如铬铁菁菁R和表面活性剂的浓度，pH，正己烷的体积，停留时间和干扰离子。在优化条件下，calibration曲线在6-230 ng mL-1范围内呈线性关系，相关系数为0.9985。基于3的信噪比（S / N）的检出限（LOD）为1.7 ng mL-1。用于测定150和30 ng ml-1的or的相对标准偏差分别为3.26％和4.41％（n = 10）。该方法显示出良好的线性，回收率以及一些优点，如灵敏度，简便性，可负担性和高可行性。该方法已成功用于测定不同水和尿液样品中的th。
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