A Simple Distance Paper-Based Analytical Device for the Screening of Lead in Food Matrices

Abstract

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−1 (R2 = 0.974) of Pb. Although, the limit of detection (LOD) of this platform was rather high, at 12.3 µg·mL−1, a series of standard additions (8.0, 9.0, and 10.0 µg·mL−1) can be used to interpret the cutoff of Pb concentrations at higher or lower than 2 µg·mL−1. 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) (n = 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.

Distance-based detection of paracetamol in microfluidic paper-based analytical devices for forensic application

“…Cate et al 30 pioneered this technique; they developed a μPAD to measure glucose, nickel, and glutathione using three different chemical detectors: enzymatic reactions, metal complexation, and nanoparticle aggregation, respectively. This technique is versatile and finds applications in clinical analysis and areas such as food quality control, 31 separation, 28 and environmental analysis. 29,32 This technique has been particularly reported for the analysis of some target compounds such as iron, 29 copper, 29 aluminum, 33 nickel, 29 potassium, 34 calcium, 35 chloride, 36,37 ascorbic acid 38 and mercury, 39 where complexation reactions occur with their specific chromogen.…”

Development of a Paper-Based Analytical Method for the Selective Colorimetric Determination of Bismuth in Water Samples

“…Based on this trend, paper-based devices are considered highly desirable analytical platforms for portable and low-cost determinations that can be used with minimal resource and instrumentation requirements and deliver swift results [32]. Since their insertion as analytical devices in 2007 by Professor G. Whiteside's research team [33], many researchers have studied a significant number of devoted paper assays and developed several fully functional paper platforms to detect and identify a vast variety of environmental, biochemical and food analytes [34][35][36][37]. The main advantages of paper, in comparison with other materials such as silicone, plastics and glass, are that (a) it is readily available at low cost; (b) the high surface area to volume ratio, (c) the spontaneous; capillary force-driven flow of liquids without external energy sources; (d) the fibrous nature that allows reagents to be stored dry and reactivated upon rehydration; (e) the modification of the paper surface in such a way to favor the chemical detection of the analyte [38,39].…”

A paper-analytical device for detecting bisphenol-A in foods

“…27 Polyethyleneimine fixed on paper was used as microfluidic channels for capturing lead in the sample solution in the presence of carminic acid. They have demonstrated that this reaction could produce a red line in the channel, the length of which was proportional to the concentration of lead in the century egg, with a detection limit of 8 μg mL −1 29…”