The fluorescence-based portable device for the determination of lead (Pb²⁺) and formalin (FA) in food samples by using Nitrogen-doped carbon dots (N-CDs) as a fluorescence probe was developed. The proposed approach, Pb^2+, and FA were determined based on the photo-induced electron transfer (PET) mechanism and the silver mirror reaction. The fluorescence intensity of the N-CDs decreased with the increase of Pb²⁺ concentration and increased with the increasing FA concentration. The fluorescence intensity of N-CDs after the reactions were measured by a filter-free fluorometer platform using a commercial camera module and a Raspberry Pi, a compact computer, as a detector and processor. The experimental results were obtained using control samples with known Pb²⁺ and FA concentrations in the 0.01-10 mg L^− 1 and 25–150 mg L^− 1, respectively. The proposed approach is simple, low-cost, and accurate for the on-site monitoring of Pb²⁺ and FA in various food samples. Of utmost importance, the proposed approach is expected to be a pioneering model for the future development of other analytes with a broad range of practical applications.

Graphical Abstract

中文翻译：

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使用掺氮碳点 (N-CD) 开发用于食品样品中铅 (II) 和福尔马林测定的基于荧光的便携式设备

开发了以掺氮碳点(N-CDs)为荧光探针的荧光便携式测定食品样品中铅(Pb ^{2+ )和福尔马林(FA)的装置。}所提出的方法、Pb ²⁺和 FA 是根据光诱导电子转移 (PET) 机制和银镜反应确定的。^{N-CDs的荧光强度随Pb 2+}浓度的增加而降低，随FA浓度的增加而增加。反应后 N-CD 的荧光强度通过无滤光片荧光计平台测量，使用商用相机模块和紧凑型计算机 Raspberry Pi 作为检测器和处理器。使用已知 Pb 的对照样品获得实验结果²⁺和 FA 浓度分别为 0.01-10 mg L ^{− 1}和 25-150 mg L ^{− 1}。所提出的方法简单、低成本且准确，可用于现场监测各种食品样品中的 Pb ²⁺和 FA。最重要的是，所提出的方法有望成为未来开发具有广泛实际应用的其他分析物的先驱模型。

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