A miniature lab-on-valve atomic fluorescence spectrometer integrating a dielectric barrier discharge atomizer demonstrated for arsenic analysis

Abstract

A miniaturized atomic fluorescence spectrometer (AFS) incorporating a dielectric barrier discharge (DBD) atomizer was developed in a lab-on-valve (LOV) configuration. The entire system integrates hydride generation, gas–liquid separation, in-situatomization and fluorescence detection. The hydride isolated from the gas–liquid separation chamber was swept by an argon flow into the atomization chamber, where free atoms of the analyte, i.e., arsenic, were formed in the DBD discharge area, which were afterwards immediately transported into the detection chamber to undergo excitation by an incident light from a hollow cathode lamp and the fluorescence was monitored using a side-on photomultiplier with its receiving window directly adhered onto one side of the detection chamber. Some important aspects concerning the performance of the entire system, i.e., the configurations of the atomization and detection chambers, the parameters governing the atomization process and the chemical and flow variables were investigated. When employing a 500 μl sample volume, a detection limit of 0.03 μg l⁻¹(As) was derived within a linear range of 0.10–5.00 μg l⁻¹. The detection limit of the present system is at the same level as that obtained by using a commercial AFS system. A sampling frequency of 80 h⁻¹ was obtained along with an RSD value of 2.8% at the level of 2.0 μg l⁻¹ As. The system was applied to the determination of arsenic in two certified reference materials, i.e., GBW10010 (rice) and GBW09101 (human hair), achieving satisfactory results.