Screening-confirmation approach for urinary alpelisib by silver-nanorod enabled portable SERS platform and LC-MS validation.

Abstract

Alpelisib, a selective PI3Kα inhibitor, benefits from reliable quantitative measurements to support exposure assessment and dose individualization. Here, we report a portable surface-enhanced Raman spectroscopy (SERS) workflow for rapid urinary screening and quantification of alpelisib using shaped-controlled silver nanoparticles, with silver nanorods selected as the substrate providing the highest SERS response among spherical, cubic, and rod-like morphologies. Key substrate-preparation and instrumental parameters were systematically optimized using a portable 785-nm Raman device, and the analytical figures of merit were thoroughly assessed in urine following a sample clean-up by protein precipitation and liquid-liquid extraction. Under optimized conditions, the diagnostic band at 993 cm⁻¹ was adopted for quantification, and the method provided a linear response from 7.93 to 113.26 µM (R² = 0.9993), with limits of detection and quantification of 2.28 µM and 7.61 µM, respectively. Precision was suitable for a rapid SERS workflow (repeatability and reproducibility RSD ≤ 8.71% and ≤ 8.25%, respectively), with accuracy close to 100% across quality-control levels. A selectivity assessment was performed in urine using an equimolar alpelisib mixture with representative pharmaceutical interferents, and the method reliability was further supported by LC-MS benchmarking, with no statistically significant differences between SERS and LC-MS results for calibration and QC samples at the 95% confidence level (two-tailed t-test). An apparent enhancement factor up to 10³ was estimated for the 993 cm⁻¹ band under the selected conditions, consistent with a predominantly electromagnetic enhancement mechanism with a plausible interfacial chemical contribution. Finally, method sustainability was discussed using the AGREE metric (overall score 0.74/1.00) as a diagnostic tool to identify improvement hotspots. Overall, this portable SERS approach provides a practical, low-instrumentation option for rapid urinary screening and quantification of alpelisib, complementary to LC-MS-based methods for comprehensive bioanalysis.