Photochemical vapor generation coupled with solution cathode glow discharge optical emission spectrometry for the highly sensitive determination of Co, Fe, and Ni

Abstract

Abstract：This study presents a sensitivity-enhanced method for the determination of Co, Fe and Ni individually based on the integration of photochemical vapor generation (PVG) with solution cathode glow discharge -optical emission spectrometry (SCGD-OES). In this approach, the chemical vapor of the target elements is generated in a PVG unit and subsequently transported to a SCGD-OES system for further analysis, thereby enhancing analytical sensitivity through improved sampling efficiency. Key parameters of both the PVG and SCGD systems were systematically optimized to achieve optimal analytical performance, including formic acid concentration, irradiation time, argon flow rate for the PVG process, as well as discharge current and discharge gap for the SCGD excitation. Under the optimized conditions, the corresponding limits of detection (LODs) for Co, Fe, and Ni are 2, 3, and 0.2 μg L -1 , respectively, representing improvements of 49 to 640 times compared with the non-coupled PVG method. The linear correlation coefficients (R 2 ) exceed 0.999 across the investigated concentration ranges, and the relative standard deviation (RSD) was less than 5% (n=9). Moreover, the accuracy and applicability of the established method were further validated through recovery tests using the GBW08608 (water) certified reference material (CRM) and spiked river water samples.