Rapid SERS inspection of carcinogenic aromatic amines in textiles by using liquid interfacial assembled Au array

Wide uses of azo dyes produce a great risk of high residuals of carcinogenic aromatic amines, and hence it is important to rapidly analyze these carcinogenic compounds in the textile products to guarantee product safety. In the present work, a surface enhanced Raman spectroscopic (SERS) method was developed for rapid detection of carcinogenic aromatic amines in textiles. In this method, target aromatic amines are extracted from textiles, and then gold nanoparticles are added to the organic extractant, which assemble into closely packed Au array at liquid interface in situ. Finally, fingerprint SERS signals of the target aromatic amines are detected on the generated Au array on the basis of strong chemical interaction between the aromatic amines and the Au surface. The proposed method provided good reproducibility with a relative standard deviation of 3.5% for ten parallel tests of benzidine. It was applied to analyze 70 textile products. To strengthen the spectroscopic data processing, a cluster analysis model was established with 50 samples to automatically identify the spectra based on the good signal reproducibility. The other 20 samples were used as test sets to validate this model. It was found that all the positive samples were successfully identified with false positive rate of 20%. With the addition of the Artificial Intelligence step, the reliability of the discriminant results can be ensured.

A functional Au array SERS chip for the fast inspection of pesticides in conjunction with surface extraction and coordination transferring

The fast inspection of the pesticide residues on fruits and vegetables requires the development of facile, sensitive and accurate methods. Surface enhanced Raman scattering (SERS) is a promising way to provide a fast inspection method, which requires significant improvements in the reproducibility and feasibility. In the present work, an SERS method was developed for the fast inspection of pesticides on fruit peels in conjunction with surface extraction and coordination transferring. In this new method, the residual pesticides were directly extracted from fruit peels with an appropriate extraction solution and then quantitatively transferred onto an organic solvent-compatible Au array SERS chip through the strong chemical interactions between the heteroatoms in the pesticides and the gold surface. The functional SERS chip was fabricated by the interfacial assembly of an Au array on a membrane, which produced dense and uniformly distributed SERS hot spots and enabled compatibility with random curvature surfaces and handheld Raman spectrometers. As a proof of concept, sulfur atoms containing thiram on apples were detected at a concentration as low as 5 ng cm-2 with good reproducibility (relative standard deviation lower than 10%). The strong interactions between the sulfur atoms and gold surface during the coordination transferring process were confirmed by the enhanced vibrations of the specified bands occurring in both the Raman and IR spectra. This surface extraction-coordination transferring-based method holds wide applicability for heteroatom-containing pesticides, as demonstrated by the detection of various S- and P-containing pesticides.

Rapid Surface Enhanced Raman Scattering (SERS) Detection of Sibutramine Hydrochloride in Pharmaceutical Capsules with a β-Cyclodextrin- Ag/Polyvivnyl Alcohol Hydrogel Substrate

Sibutramine hydrochloride (SH) is a banned weight-loss drug, but its illegal addition to health products is still rampant. This suggests a very urgent need for a fast and precise detection method for SH. Surface Enhanced Raman Scattering (SERS) is a promising candidate for this purpose, but the weak affinity between SH and bare metal limits its direct SERS detection. In the present work, β-cyclodextrin was capped in situ onto the surface of Ag nanoparticles to function as a scaffold to capture SH. The obtained Ag nanoparticles were encapsulated into polyvinyl alcohol (PVA) to fabricate a SERS active hydrogel with excellent reproducibility. A facile SERS strategy based on such substrate was proposed for trace SH quantification with a linear range of 7.0–150.0 µg·mL^–1, and a detection limit low to 3.0 µg·mL⁻¹. It was applied to analyze seven types of commercial slimming capsules with satisfactory results, showing good prospect for real applications.