Colloidal gold clusters formation and chemometrics for direct SERS determination of bioanalytes in complex media

EDUARDO A. CORONADO

SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY.

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2020 vol. 224 p. 117380 - 117380

1386-1425

n this work, we report the sensitive and selective sensing of the purine bases adenine and guanine in the urine matrix by using surface-enhanced Raman spectroscopy (SERS) and a colloidal SERS substrate. To identify suitable conditions for quantitative analysis, the pH dependence of spectra of adenine, guanine, urine simulant, and their mixtures was studied on gold nanoparticles suspension. Interestingly, although the urine matrix promotes the analytes signal suppression and overlapping bands, it can also cause an improvement in the repeatability of the SERS measurements. This effect was associated with the relatively controlled formation of small-sized gold clusters and it was investigated both experimentally and theoretically. Furthermore, a correlation constrained multivariate curve resolution-alternating least squares (MCR-ALS) method was developed to resolve overlapping SERS bands and to quantify physiologically relevant (micromolar) concentrations of the bioanalytics. The perform