Label-free SERS for natural product provenance

Hughes, Juanita, Izake, Emad L., Lott, William B., & Ayoko, Godwin A. (2014) Label-free SERS for natural product provenance. In 24th Anniversary World Congress on Biosensors, 28-30 May 2014, Melbourne Convention and Exhibition Centre, Melbourne, VIC. (Unpublished)

Abstract

Introduction

Natural product provenance is important in the food, beverage and pharmaceutical industries, for consumer confidence and with health implications. Raman spectroscopy has powerful molecular fingerprint abilities. Surface Enhanced Raman Spectroscopy’s (SERS) sharp peaks allow distinction between minimally different molecules, so it should be suitable for this purpose.

Methods

Naturally caffeinated beverages with Guarana extract, coffee and Red Bull energy drink as a synthetic caffeinated beverage for comparison (20 µL ea.) were reacted 1:1 with Gold nanoparticles functionalised with anti-caffeine antibody (ab15221) (10 minutes), air dried and analysed in a micro-Raman instrument. The spectral data was processed using Principle Component Analysis (PCA).

Results

The PCA showed Guarana sourced caffeine varied significantly from synthetic caffeine (Red Bull) on component 1 (containing 76.4% of the variance in the data). See figure 1. The coffee containing beverages, and in particular Robert Timms (instant coffee) were very similar on component 1, but the barista espresso showed minor variance on component 1. Both coffee sourced caffeine samples varied with red Bull on component 2, (20% of variance).


Figure 1 PCA comparing a naturally caffeinated beverage containing Guarana with coffee.


Discussion

PCA is an unsupervised multivariate statistical method that determines patterns within data. Figure 1 shows Caffeine in Guarana is notably different to synthetic caffeine. Other researchers have revealed that caffeine in Guarana plants is complexed with tannins. Naturally sourced/ lightly processed caffeine (Monster Energy, Espresso) are more inherently different than synthetic (Red Bull) /highly processed (Robert Timms) caffeine, in figure 1, which is consistent with this finding and demonstrates this technique’s applicability. Guarana provenance is important because it is still largely hand produced and its demand is escalating with recognition of its benefits. This could be a powerful technique for Guarana provenance, and may extend to other industries where provenance / authentication are required, e.g. the wine or natural pharmaceuticals industries.

Impact and interest:

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ID Code: 72592
Item Type: Conference Item (Poster)
Refereed: Yes
Additional URLs:
Keywords: biosensors, label-free, SERS, Surface Enhanced Raman Spectroscopy, food provenance, chemometrics, Principle Component Analysis (PCA)
Subjects: Australian and New Zealand Standard Research Classification > MATHEMATICAL SCIENCES (010000) > STATISTICS (010400)
Australian and New Zealand Standard Research Classification > MATHEMATICAL SCIENCES (010000) > STATISTICS (010400) > Applied Statistics (010401)
Australian and New Zealand Standard Research Classification > CHEMICAL SCIENCE (030000)
Australian and New Zealand Standard Research Classification > CHEMICAL SCIENCE (030000) > ANALYTICAL CHEMISTRY (030100)
Australian and New Zealand Standard Research Classification > CHEMICAL SCIENCE (030000) > ANALYTICAL CHEMISTRY (030100) > Analytical Spectrometry (030101)
Australian and New Zealand Standard Research Classification > CHEMICAL SCIENCE (030000) > ANALYTICAL CHEMISTRY (030100) > Sensor Technology (Chemical aspects) (030107)
Divisions: Current > Schools > School of Chemistry, Physics & Mechanical Engineering
Current > Institutes > Institute of Health and Biomedical Innovation
Current > QUT Faculties and Divisions > Science & Engineering Faculty
Copyright Owner: Copyright 2014 The Author(s)
Deposited On: 05 Jun 2014 22:48
Last Modified: 05 Jun 2014 22:50

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