Determination of glucose content by means of visible micro-Raman spectroscopy and interval partial least square multivariate analysis

Micro-Raman spectroscopy and interval Partial Least Square (iPLS) multivariate analysis have been used for determining glucose concentration in various commercial sport drinks. By employing a visible excitation light (633 nm), micro-Raman spectra in the 600-1600 cm^-1 wavenumber shift region have been recorded, showing well defined and separated vibrational fingerprints of the various contained sugars (glucose, fructose and sucrose). Glucose content was quantified by using the iPLS analysis based on a model built by employing aqueous glucose solutions as reference samples. The estimated glucose concentrations are in good agreement with the values obtained by using a biochemical assay. These results represent a significant step towards the development of a fast, simple, cost-effective Raman-based method for glucose quantification in products of food and beverage industry, alternative to expensive, time-, sample- and chemicals-consuming biochemical assays currently used in production and quality control processes.