Determination of Extractable Organic Chlorine and Bromine by Probe Injection Dual-Microplasma Atomic Emission Spectrometry

Abstract

A probe injection dual-microplasma spectrometer is evaluated as a low-cost alternative for the determination of extractable organic chlorine and bromine (EOCl and EOBr). The system consists of two 350 kHz plasmas sustained in the same stream of helium and a probe for sample application in the interplasma region. The sample was applied with a microsyringe into a small cup on the sample probe. Subsequently, the extraction solvent was gently evaporated, and the sample cup was pushed into the interplasma region. The first plasma was in direct contact with the sample probe and served to rapidly vaporize the sample material. The vaporized sample was then transferred to the second plasma, where atomic emission was measured for the determination of EOCl and EOBr. For both Cl and Br, 120 pg detection limits and 1000:1 halogen-to-carbon selectivities were obtained, and responses were linear over 3 orders of magnitude.

Needle electrode-based microplasma formed in a cavity chamber for optical emission spectrometric detection of volatile organic compounds through a filter paper sampling

“…Further increasing the power supply usually increases the emission background, which in turn influences the emission measurement. Except for the emission bands at 309.2 nm and 589.2 nm, the C2 and CH emission bands for trichloromethane are hardly observed in the spectrum, which may be attributed to the relatively low power of the microplasma that can hardly break the CHCl3 molecule [14]. In general, the CH emission increases with an increasing number of H atoms in the molecule.…”

“…Currently the main drawback of conventional microplasma devices for VOC detection is the limited life time caused by the cathode sputtering and the fluctuation of the discharge zone due to the disturbance from the substrates, the deposition on the configurations, and the parasitic capacitance [6,13]. Another problem in using a traditional microplasma detector is that they always suffer from overheating due to the direct contact between the microplasmas and the substrates [14]. The heat from the plasma region would increase the temperature of the probe or sample mount, with subsequent losses of volatile sample constituents.…”