In this work we propose for the first time, a paper-based test strip to analyse Cu²⁺ content in sugar cane spirits, which, due to its simplicity, high portability and fast analytical response (3 min), can be easily applied to in situ analyses by producers. The test strip was developed aiming: i) identify qualitatively the Cu²⁺ content in sugar cane spirits, and, ii) determine quantitatively the Cu²⁺ content using a digital image method employing a smartphone. The paper-based test strip was functionalized with cuprizone and optimized through a Box-Behnken, an experimental design for obtaining the best reaction conditions. Based on qualitative method with naked eyes approach performed by six volunteers analyst untrained, the method present a percentage of accuracy of 93%. For the quantitative analysis, it was determined the metal content at a level of statistical agreement with the reference method, as well as it was obtained the dynamic linear range from 2 to 13 mg L⁻¹ with limits of detection and quantification of 0.034 and 0.103 mg L⁻¹, respectively. Furthermore, the quantitative method showed a reliable precision with an RSD of 4.3% (n = 10) and the recovery of Cu²⁺ ranged from 80 to 103.8%.

在这项工作中，我们首次提出了一种纸质测试条，用于分析甘蔗油中的Cu ²⁺含量，由于其简单性，高便携性和快速的分析响应（3分钟），可以很容易地应用于生产者的原位分析。开发该测试条的目的是：i）定性确定甘蔗油中的Cu ²⁺含量，ii）定量确定Cu ²⁺使用采用智能手机的数字图像方法获取内容。纸质试纸已用铜酮进行了功能化，并通过Box-Behnken（用于获得最佳反应条件的实验设计）进行了优化。基于六名未经培训的志愿者分析人员采用肉眼定性方法，该方法的准确率达93％。为了进行定量分析，使用参考方法确定了金属含量的统计一致性水平，并获得了2至13 mg L ^-1的动态线性范围，检出限和定量限为0.034和0.103分别为mg L ^-1。此外，定量方法显示出可靠的精度，相对标准偏差为4.3％（n = 10），并且铜的回收率^2+的范围从80到103.8％。