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A new miniaturized liquid extraction cartridge equipped with a functional porous polytetrafluoroethylene membrane was developed for the determination of formaldehyde in gaseous samples. The functional polytetrafluoroethylene membrane allows gas to pass through while repelling both water‐based and organic‐based liquids. A derivatization reagent for formaldehyde, 2,4‐dinitrophenylhydrazine, was placed in the cartridge and gaseous samples are collected through the cartridge at 20 ml/min for 30 min. Formaldehyde in the gaseous sample is captured as the corresponding 2,4‐dinitrophenylhydrazine hydrazone, and an aliquot of the sample collection solution can be directly subjected to high‐performance liquid chromatographic analysis. The limit of quantification for the developed method was 5 ng/L formaldehyde in gas with a sampling volume of 600 ml. Proof‐of‐concept for formaldehyde determination in an aqueous sample was demonstrated using the developed cartridge in a purge‐and‐trap extraction setup. [ABSTRACT FROM AUTHOR]

Gaseous hydrogen selenide (H2Se) generated by the addition of sodium tetrahydroborate (NaBH4) into an acidic aqueous sample was collected using an aqueous ammonia solution. The selenium (Se) concentration was determined using graphite furnace atomic absorption spectrometry (AAS). Several experimental conditions, such as the type of the collection solution, volume of NaBH4 and hydrochloric acid, and collection time, were optimized. In addition, the effect of coexisting ions was quantitatively evaluated and eliminated. The limit of detection for Se in a standard water sample was 1.3 ng/mL. The additional recovery of spiked Se in tap water and river water samples ranged from 98 ± 2.4 to 100 ± 2.2%. The proposed method facilitates simple and sensitive analysis for Se in water samples without H2Se gas generator for AAS. [ABSTRACT FROM AUTHOR]