O-phthalaldehyde assisted surface enhanced Raman spectroscopy selective determination of trace homocysteine in serum

High plasma homocysteine (Hcy) levels may indicate cardiovascular disease. However, sensitive and selective determination of Hcy remains a major challenge. Herein, we present a sensing strategy for Hcy by surface enhanced Raman scattering (SERS) method along with a specific reaction of o-phthalaldehyde (OPA) and Hcy. The obtained adduct 2-(1-carboxyl-3-thiopropyl)-1-isoindolinone (Hcy-OPA) can be directly detected by SERS using gold nanoparticles (Au NPs) as the substrate. The developed SERS method displays superior sensitivity (low detection limit of 2.50 × 10 −12 mol L −1 ) with a broad linear range (5.00 × 10 −10 −5.00 × 10 −6 mol L −1 ). As a proof of real application, it can be used to detect Hcy in bovine serum samples with a concentration as low as 5.00 × 10 −9 mol L −1 , which is free from the interference of the other amino acids and glutathione.