Interdisciplinary Program of Biomedical Sciences, Graduate School, Chulalongkorn University, Bangkok 10330, Thailand.
Department of Clinical Chemistry, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok 10330, Thailand.
Biosensors (Basel). 2021 Mar 22;11(3):90. doi: 10.3390/bios11030090.
A simple and rapid distance paper-based analytical device (dPAD) for the detection of lead (Pb) in foods is proposed herein. The assay principle is based on competitive binding between carminic acid (CA) and polyethyleneimine (PEI) to Pb in a food sample. The paper channels were pre-immobilized with PEI, before reacting with a mixture of the sample and CA. Pb can strongly bind to the CA; hence, the length of the red color deposition on the flow channel decreased as a lower amount of free CA bound to PEI. The dPAD exhibited good linear correlation, with ranges of 5-100 µg·mL ( = 0.974) of Pb. Although, the limit of detection (LOD) of this platform was rather high, at 12.3 µg·mL, a series of standard additions (8.0, 9.0, and 10.0 µg·mL) can be used to interpret the cutoff of Pb concentrations at higher or lower than 2 µg·mL. The presence of common metal ions such as calcium, magnesium, nickel, and zinc did not interfere with the color distance readout. The validity of the developed dPAD was demonstrated by its applicability to screen the contamination of Pb in century egg samples. The results obtained from the dPAD are in accordance with the concentration measured by atomic absorption spectroscopy (AAS) ( = 9). In conclusion, this proposed dPAD, combined with the standard addition method, could be applied for screening Pb contamination in food matrices. This platform is, therefore, potentially applicable for field measurements of Pb in developing countries, because it is cheap and rapid, and it requires no significant laborious instruments.
本文提出了一种用于检测食品中铅（Pb）的简单快速的基于纸张的分析装置（dPAD）。该测定原理基于在食品样品中，胭脂红酸（CA）与聚乙烯亚胺（PEI）与 Pb 之间的竞争结合。在与样品和 CA 的混合物反应之前，纸通道先用 PEI 进行预固定。Pb 可以与 CA 强烈结合；因此，由于与 PEI 结合的游离 CA 量减少，红色颜色在流动通道上的沉积长度变短。dPAD 表现出良好的线性相关性，Pb 的范围为 5-100 µg·mL（ = 0.974）。尽管该平台的检测限（LOD）相对较高，为 12.3 µg·mL，但可以使用一系列标准添加物（8.0、9.0 和 10.0 µg·mL）来解释 Pb 浓度高于或低于 2 µg·mL 的截止值。常见金属离子（如钙、镁、镍和锌）的存在不会干扰颜色距离读数。该开发的 dPAD 的有效性通过其在皮蛋样品中检测 Pb 污染的适用性得到了证明。dPAD 获得的结果与原子吸收光谱法（AAS）测量的浓度相符（ = 9）。总之，这种提出的 dPAD 结合标准添加方法可用于筛选食品基质中的 Pb 污染。由于其价格低廉、快速，并且不需要复杂的仪器，因此该平台非常适合发展中国家的 Pb 现场测量。
