Paper swab based SERS detection of non-permitted colourants from dals and vegetables using a portable spectrometer

Kumar, Aditya and Santhanam, Venugopal (2019) Paper swab based SERS detection of non-permitted colourants from dals and vegetables using a portable spectrometer. In: ANALYTICA CHIMICA ACTA, 1090 . pp. 106-113.

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Abstract

Rising concern about the use of non-permitted colourants, in common food items such as dals and green vegetables sold in Indian markets, have led to a demand for low-cost point-of-use chemical analysis tools. Conventional food-analysis techniques involving tedious sample preparation protocols are not suited for in-field applications. Surface Enhanced Raman Spectroscopy (SERS) is an analytical technique that is well-suited for point-of-use chemical analysis with molecular level detection capability, which can also serve as a quality assurance tool for businesses. Effective and rapid signal collection from a large-area sample within a field-setting using disposable, low-cost SERS substrates is a key challenge in implementing such a solution. Herein, we demonstrate the use of inkjet-printed thin films comprising of robust nanostructuredsilver as flexible, paper-based SERS (P-SERS) swabs for the direct detection of Metanil Yellow (MY) from toor dal (yellow split pigeon peas) samples and Malachite Green (MG) from green peas and green chillies. The macroscopic uniformity of these thin-films in combination with a portable Raman spectrometer equipped with orbital raster scanning (ORST) technology for signal collection results in an unprecedented precision (RSD similar to 1.6%) upon characterizing samples saturated with Rhodamine-6G (R6G), a standard Raman probe. As several food-cleansing products have appeared in the marketplace, the adulterant removal efficacy of some commercially available `washes' as well as products such as `ozoniser', which was determined by SERS characterization of swabs before and after use, is also reported.

Item Type:	Journal Article
Publication:	ANALYTICA CHIMICA ACTA
Publisher:	ELSEVIER
Additional Information:	copyright of this article belong to ELSEVIER
Keywords:	Inkjet printed SERS swab; Food adulteration; Portable Raman spectrometer; Surface enhanced Raman spectroscopy
Department/Centre:	Division of Mechanical Sciences > Chemical Engineering
Date Deposited:	05 Dec 2019 10:22
Last Modified:	05 Dec 2019 10:22
URI:	http://eprints.iisc.ac.in/id/eprint/63881

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