Sensitive and Selective Detection of New Red Colorant Based on Surface-Enhanced Raman Spectroscopy Using Molecularly Imprinted Hydrogels

Abstract

A polyacrylamide-based molecularly imprinted hydrogel (MIH) doped with positively charged gold nanoparticles (Au NPs) has been synthesized via a free radical polymerization of acrylamide (AM) aqueous solution containing positively charged Au NPs as a Raman active substrate, New Red colorant as a template molecule, N,N’-methylenebis(acrylamide) as a crosslinking agent, and potassium persulfate as an initiator. The Au NPs-doped MIHs were subsequently explored as a Raman active substrate for the sensitive and selective detection of New Red colorant via surface-enhanced Raman spectroscopy (SERS). The logarithmic intensity of the characteristic peak of New Red at 1572 cm−1 was proportional to the logarithmic concentration of New Red with a detection linear range of 1.64 × 10−6 to 1.64 × 10−4 M and a limit of detection (LOD) of 1.64 × 10−7 M. The recoveries ranged from 86.3% to 100.6% with a relative standard deviation (RSD) in the range of 2.3% to 7.7%. The RSD and recovery rates for the detection of New Red spiked in a sports drink sample were 1.8% to 7.7% and 91.0% to 97.1%, respectively. These results showed that SERS combined with MIHs as Raman active substrates could provide a sensitive, selective, and effective approach for the detection of the New Red colorant in beverage matrix.

Improved food additive analysis by ever-increasing nanotechnology

“…In addition, the organic molecule β-cyclodextrin can also be used to modify the electrode to enhance the electrochemical detection in soft drinks due to its good adsorption capacity [ 36 , 53 ]. Although the most commonly used method for detecting colorants in soft drinks is to modify the working electrode with nanotechnology, in recent years, some methods other than electrochemical sensing have been reported to better detect colorants in soft drinks [ 54 – 57 ]. Among them, surface enhanced Raman spectroscopy (SERS) as a highly sensitive nanotechnology can also be used to detect colorants in soft drinks.…”

Ultra-high SERS detection of consumable coloring agents using plasmonic gold nanostars with high aspect-ratio spikes

“…Synthetic azo colorant pigment molecules are illegally used as color additives because of their advantages of low price, excellent tinting, and improved stability for beverages, drinks, candies, and other food additives. [1][2][3][4] However, these pigment molecules are serious threats to human health because of their cytotoxicity, carcinogenicity, and hypersensitivity effects as they can decompose into carcinogenic amine materials. 2,[5][6][7] Therefore, there remains an urgent need for an analytical technique to prevent this food fraud which can offer a sensitive, rapid, and effective detection of these pigment molecules.…”

Synthesis of Molecularly Imprinted Polymer via Emulsion Polymerization for Application in Solanesol Separation

“…In 1972, Wulff et al successfully prepared an MIP for the first time [4]. Today, molecular imprinting technology is widely used in solid-phase extraction [5,6], chromatographic separation [7,8], bionic sensing [9], membrane separation [10], the food industry [11,12], natural drug separation [13], medicine [14], and environmental monitoring [15], among other applications. The methods of the synthesis of MIPs include bulk polymerization, solution polymerization, dispersion polymerization, suspension polymerization, and emulsion polymerization.…”