Ensuring sample quality and integrity is vital in so many different industries, helping to establish, for example, the authenticity, purity and safety of the food and drink we consume, the medication we rely on, and the various products used in agriculture for crop production. Aqsens has developed liquid fingerprinting, an innovative technology with the potential to revolutionize the way scientists establish the identity, composition and origins of a range of sample types in industries as diverse as oil and gas, pharma, food and beverage, and agrochemicals.
What is liquid fingerprinting?
Most people are familiar with the traditional definition of a fingerprint – the impression of a fingertip on any surface – but, in the world of science, the term fingerprint has an alternative meaning. To scientists, the word fingerprint can also refer to a trait or characteristic that is specific to a particular substance, enabling its place of origin or functionality to be determined, or to analytical evidence such as a chromatogram or mass spectrum which categorically establishes a sample’s identity. A more recent development from Aqsens is liquid fingerprinting, a rapid, straightforward time-resolved fluorescence (TRF) technique that can be used qualitatively or quantitatively, with many potential applications.
Liquid fingerprinting takes advantage of the long fluorescence lifetime – typically in the millisecond range – of a lanthanide-based dye. The dye is mixed with a sample in liquid format, and the sample-dye complex applied to an array of non-specific surface chemistries, each of which reacts differently. Some of the surface chemistries will interact with the sample-dye complex to protect and stabilize the dye or to enhance the fluorescent signal, while others will have the opposite effect and quench the signal. The benefit of using non-specific chemistries is that the array has the capability to interact with many compounds, yet only a limited number of sensors are required. This combination of multiple interactions generates a matrix of high and low TRF signals that is specific to the individual sample, allowing its unique fingerprint to be determined. A great deal of information can be acquired for each sample – far more than would be obtained using the same number of specific chemistries – making characterization easier. This is a big advantage compared to traditional analytical techniques such as Fourier transform infrared spectroscopy (FTIR). Liquid fingerprinting can, for example, distinguish between a fake drug containing the same constituents as the authentic product but in a different formulation, while the FTIR spectra of the two compounds may be so similar that they cannot be distinguished.
A variety of applications
Liquid fingerprinting has potential for a wide range of applications. Two particularly important uses – product authentication and quality control – are described below.
In addition to meeting stringent quality control requirements, the food and beverage industry has a need to detect adulterated and imitation products, ensuring the authenticity of all food and drink. For instance, a wine may be marketed as being a particular vintage or from a certain region, but how can you tell if this is really the case? Liquid fingerprinting may hold the key. By comparing, for example, the liquid fingerprint of a genuine Bordeaux wine with that of another wine, it is possible to establish whether or not the sample tested is authentic. If the fingerprints do not match, and the sample is actually a blend of different wines, then an indication of the percentage Bordeaux content can be obtained; a sample that is a close fingerprint match may contain 90 % Bordeaux wine, while a poor match may have just 50 %. This technique could equally well be applied to the determination of the authenticity of other alcoholic or soft drinks. In another experiment, a professional sommelier and a layman were asked to identify nine wines, simultaneously analyzing the same wines using liquid fingerprinting. The sommelier and the layman correctly identified most, but not all, of the wines; liquid fingerprinting, however, was 100 % correct, showing the effectiveness of the technique for this purpose.
A recently published study performed in collaboration with Alko Oy, Finland’s national alcoholic beverage retailing monopoly , has demonstrated how liquid fingerprinting can provide crucial information to support decision making in the quality control of both wine-making processes and the end product. The technique has also been successfully used to distinguish between some other types of beverage , for example identification of the source of bottled waters according to their ion content, an application that could potentially be used for process monitoring in the oil and gas industry, where the ion content of oil-field produced waters must be analyzed.
Wide-ranging possibilities for future applications
Although, to date, the majority of studies have been performed using wine, investigations into the use of liquid fingerprinting for other applications is ongoing. In addition to the applications described above, the technique has so far been used to distinguish between genuine pesticides and imitation products containing the same active ingredient; between authentic drugs and fake counterparts comprising the same constituents but in a completely different formulation; and to identify spices, such as curry powder, where one of the more expensive ingredients has been omitted from the end product. In the future, there may also be potential for liquid fingerprinting to be applied to anti-doping control in sport. The possibilities are simply endless.
Contact us if you would like to learn more about the possibilities within your industry.
J.J. Siivonen, P.I. Väisänen, S.A. Tiittanen, M.M. Lehmusto, P. Lehtonen, E. Patrikainen, T. Teimonen, N. Törnkvist, P. Mundill, P. Hänninen and H. Härmä.Novel non-specific liquid fingerprint technology for wine analysis: a feasibility study. Australian Journal of Grape and Wine Research, 20: 172–177.
 Pekka E. Hänninen, Joonas J. Siivonen, Pave I. Väisänen, Satu A. Tiittanen, Mirva M. Lehmusto,Timo Teimonen, Niklas Törnkvist, Mari A. Sandell, Antti J. Knaapila, Paul Mundill,and Harri J. Härmä. Fuzzy Liquid Analysis by an Array of Nonspecifically Interacting Reagents: The Taste of Fluorescence. J. Am. Chem. Soc2013, 135 (20), pp 7422–7425.