Abstract: A method was developed for the rapid and sensitive detection of histidine using silver dendrimers as a substrate for surface-enhanced Raman spectroscopy in combination with azo-coupling reaction. The azo-coupling reaction of 3-aminobenzylamine, 3-anilinosulfonic acid or 2-fluoro-4-mercaptoaniline (2-F-PATP) with histidine was investigated. The Raman spectra of the resulting products revealed that 2-F-PATP gave the best Raman fingerprint for histidine, with a limit of detection (LOD) of 10-21 mol/L. The characteristic peaks (at 1 387 and 1 432 cm-1) of the azo-coupling product of histidine were selected for quantitative analysis, and the intensity of the characteristic peaks in the Raman spectra showed a linear relationship with histidine concentration in a certain range, with correlation coefficients (R2) of 0.975 61 and 0.968 84, respectively. This method can be used for the determination of bovine serum albumin, human serum albumin, α-lactalbumin and apple juice. The proposed method is sensitive and simple to use, and has good application potential.

Key words: surface-enhanced Raman spectroscopy; silver dendritic; azo-coupling reaction; histidine