Rapid identification and quantification of diquat in biological fluids within 30 s using a portable Raman spectrometer

Rapid detection of diquat (DQ) is essential in clinical diagnosis and rescue. Here, we developed a fast, simple-yet-practical detection strategy for the reliable identification and quantification of DQ in biological fluids. Based on surface-enhanced Raman spectroscopy (SERS), point-of-care detection was realized under the acidic condition with gold nanoparticles as the substrate. Under optimal experimental conditions, the detection limits of the strategy were 17.5 ppb and 1.99 ppm in human urine and gastric juice, respectively. High specificity and selectivity of the SERS strategy were demonstrated using common pesticides and coexisting biological sub-stances. The method was also used to detect biofluids from 5 patients and urine samples from 10 healthy vol-unteers. The results were in high agreement with spectrophotometric and clinical liquid chromatography-mass spectrometry methods. The volume of urine samples required for this technique is merely 20 mu L, and no prep-aration of the samples is required. Compared to traditional methods used in clinical settings, SERS-based methods are capable of real-time measurements that accurately provide rapid detection and response in non-laboratory settings, with great potential for on-site and point-of-care testing.

Automated summary

In this study, a fast and simple detection strategy for diquat (DQ) in biological fluids was developed using surface-enhanced Raman spectroscopy (SERS). The method achieved point-of-care detection under acidic conditions with gold nanoparticles as the substrate. The strategy demonstrated high specificity and selectivity, and was validated using clinical methods. Compared to traditional clinical methods, SERS-based methods offer real-time measurements and have great potential for on-site and point-of-care testing.