[Study on Detection of Prohibited Pigments in Drinks Using Paper-Based SERS Substrates].

In this paper, a novel paper-based Surface enhanced Raman spectroscopy (SERS) substrate with high sensitivity, good uniformity and popular price is developed via liquid/liquid interface self-assembly technique. Three pigment, rhodamine B, sunset yellow and chrysoidine were detected through paper-based SERS substrates using a portable Raman spectrometer. The structures of the three pigments were investigated and vibrational modes of characteristic peaks of three pigments were assigned. SERS spectra of rhodamine B, sunset yellow and chrysoidine in aqueous solution with different concentrations were detected respectively. Rhodamine B, sunset yellow and chrysoidine in drinks were also detected in drinks without any pretreatment. Within a certain range of concentrations, it meets certain function. For rhodamine B and sunset yellow, the relationship between concentration and Raman peak intensity is on an index curve, while for chrysoidine, the relationship is linear. In addition, high recoveries are achieved for detecting rhodamine B, sunset yellow and chrysoidine in drinks, which indicated our method is suited for semi-quantitative analysis for the concentration of rhodamine B, sunset yellow and chrysoidine in drinks. Surface-enhanced Raman spectroscopy provides an easy approach to fast and efficient detection for multiple pigments in drinks and can be used for quality control and market monitoring of drinks.

Fabrication of transparent SERS platform via interface self-assembly of gold nanorods and gel trapping technique for on-site real time detection.

A transparent SERS platform was fabricated via the gel-trapping method coupled with a liquid/liquid interface self-assembly technique. We employed gold nanorods as the building blocks for interface self-assembly because of their strong localized surface plasmons upon excitation by infrared radiation. Based on a "top cover" configuration, this transparent SERS platform endows high signal reproducibility for directly detecting liquid samples by confining the sample droplet into a regular shape. The Au NR PDMS platform was able to directly detect crystal violet in aqueous solutions down to 10 ppb level with high enhancement factor (0.87 × 10(5)) and signal uniformity (RSD = 3.9%). Furthermore, SERS-based anti-fungal agent detection on a fish scale was demonstrated by simply covering the fish scale with a tailored GNRs PDMS film. The experimental results clearly show that the Au NR PDMS SERS platform has great potential for on-site real time detection of contaminants in water as well as on curved surfaces.

[Detection of Cinnabars in Mongolian Medicines Using Raman Spectroscopy].

Cinnabar could soothe the nerves and the powder of cinnabar is always added in traditional Chinese medicine or mongolian medicines. The surface-enhanced Raman spectrum of cinnabar was identified using a portable Raman spectrometer and most structure vibration information was obtained. The results show that the Raman peaks of cinnabars were located at 253, 290, 343 cm(-1) and this three Raman characteristic peaks were selected for cinnabar identification. Meanwhile, the Raman spectra of several mongolian medicines were collected. The results showed that Raman signal of cinnabar could be observed in several mongolian medicines which contain cinnabar and Raman signal of cinnabar couldn't be detected in several mongolian medicines without cinnabar. In addition, the cinnabar in the oral ulcer powder was semi-quantitative analyzed and the limit of detection could reach to 10% of mass fraction. The relationship between the doped amount of cinnabar in the oral ulcer powder and the Raman intensity of characteristic peak was fitted and the correlation coefficient (r) was 0.995 9, which validated the accuracy of the result. This Raman analysis method for cinnabar detection is rapid, simple and accurate and it can be applied widely in mongolian medicines determination.