Research undertaken at the University of Lincoln, UK, which has since been applied in the area of fuel fraud detection, has been detailed to the scientific community in an academic journal.

The ground-breaking core technology, to develop a stable silver colloid (silver nanoparticles which remain suspended indefinitely in solution), was developed and patented in the University’s forensic laboratories by Professor Peter White.

He subsequently used this material to develop a novel Surface Enhanced Raman Scattering (SERS) spectroscopic method together with a portable instrument to detect and combat fuel fraud.

Professor White’s colloid research work, which was patented in 2007, has been acknowledged as the first time a stable and reproducible silver colloid has been produced.

Following the discovery, batches were monitored for a year to ensure they met all the demands required for a commercially available SERS reagent (a substance or compound that is added to a system in order to bring about a chemical reaction). These include having an acceptable shelf-life, good batch-to-batch reproducibility, a high enhancement factor and commercially viable cost. The properties of this colloid also open up other potential chemical and medical applications.

Details of this underpinning research have now been published in the Journal of Raman Spectroscopy.

Professor White said: “I saw the potential for Raman spectroscopy in forensic science and published and patented a number of novel applications including the development of SERS active markers more than 12 years ago. However, these required a stable silver colloid to become commercially acceptable applications. To resolve this problem I knew we had to change the charge of the colloid surface for it to remain stable and in 2007 we finally had our Eureka moment. Up until this point nobody had been able to produce a silver colloid that was stable enough for commercial use. It was a first for the UK and was a definitive piece of research”.

Governments often tax or subsidise fuel products to generate revenues, or stimulate their economies, and both of these practices are subject to fraud. Fuel marking has been shown to be effective in controlling illegal activity.

After retiring from the University, Professor White developed the SERS fuel fraud application for DeCipher Pte Ltd, which now uses this technology for measuring markers in fuel to identify and control malpractices and combat fuel smugglers on a global scale. The SERS instruments used are portable, give high specificity and sensitivity for fuel markers and the analysis is quick, clear and decisive. This has significant advantages over existing systems and is believed to be the first commercial and forensic application of SERS.

The technology is based on detection and measuring the fuel markers with lasers. The secret of the project’s success is in linking these molecules to silver nano-particles to get a 10-100 million times increase in sensitivity. The stability of the colloid is critical to the process and DeCipher is licensed to use the University’s patented colloid technology. To ensure its lead in this market, DeCipher continues to sponsor collaborative postgraduate research projects with the University of Lincoln.

Professor White, who was Professor of Forensic Science at the University of Lincoln until his retirement in 2009, began his career as an Organic Research Chemist with Glaxo Laboratories in 1968.

He then joined the Metropolitan Police Forensic Science Laboratory, working in a research group which had a worldwide reputation for developing new analytical methods to solve casework-related problems. He developed one of the first multi-wavelength high-performance liquid chromatography (HPLC) detectors and new methods for the trace analysis of dyes, with many still in use now.

After 15 years Professor White joined and became the Director of the Forensic Science Unit at the University of Strathclyde, where he introduced and developed the technique of Raman spectroscopy for the analysis of trace materials of forensic interest. For his contributions to the advancement of forensic and analytical chemistry he was awarded Fellowship of the Royal Society of Chemistry in 1995.

In 2003, he was appointed the Professor of Forensic Science at the University of Lincoln where he continued to pursue his Raman research interests, in particular the development of a stable silver colloid.

Professor White was appointed a Fellow of the Forensic Science Society in 2007 and in 2009 took early retirement to set up his own Forensic and Analytical Chemistry Consultancy, “ReForensics”.

In addition to being retained as the R&D Consultant for DeCipher Pte Ltd, Professor White is also working on other counterfeit detection projects in the Middle East and Denmark. He is also a Guest Professor at the Technical University of Denmark.

The paper ‘Preparation and characterisation of a stable silver colloid for SER(R)S spectroscopy’ is published in the Journal of Raman Spectroscopy Volume 45, pages 32-40 DOI: 10.1002/jrs.4412