Filter paper-based optical sensors (FPOS) offer rapid and sensitive quantification of analytes. Herein we report, a simple, sensitive, selective and low-cost FPOS for Th(IV) determination. Filter paper strips, impregnated with Morin reagent are reacted with Th(IV) yielding an intense yellow complex whose RGB (red/green/blue) color intensities made the basis of the assessment. A plot of the blue channel color absorbance versus Th(IV) concentration was linear up to 4.0 µg mL− 1 with a detection limit of 0.1 µg mL− 1. The proposed method was accurate, precise and reliable for analyzing complex certified rock samples in excellent compliance with the certified values.

中文翻译：

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基于滤纸的光学传感器用于岩石样品中钍的高灵敏度评估

基于滤纸的光学传感器 (FPOS) 可对分析物进行快速、灵敏的量化。在此，我们报告了一种用于 Th(IV) 测定的简单、灵敏、选择性和低成本的 FPOS。用 Morin 试剂浸渍的滤纸条与 Th(IV) 反应，产生强烈的黄色复合物，其 RGB（红/绿/蓝）颜色强度是评估的基础。蓝色通道颜色吸光度与 Th(IV) 浓度的关系图在高达 4.0 µg mL-1 的范围内呈线性，检测限为 0.1 µg mL-1。所提出的方法准确、精确和可靠，可用于分析复杂的认证岩石样品非常符合认证值。