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 x 10-12 mol L-1) with a broad linear range (5.00 x 10- 10 -5.00 x 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 x 10-9 mol L-1, which is free from the interference of the other amino acids and glutathione.

Automated summary

We propose a sensing strategy for Hcy using surface enhanced Raman scattering (SERS) method and the 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. This developed SERS method shows superior sensitivity with a low detection limit and a broad linear range, and it can detect Hcy in bovine serum samples without interference from other amino acids and glutathione.