A critical comparison of constant and pulsed flow systems exploiting gas diffusion

作者：Silva Claudineia Rodrigues; Henriquez Camelia; Frizzarin Rejane Mara; Guidetti Zagatto Elias Ayres; Cerda Victor

来源：Talanta, 2016, 148: 596-601.

DOI：10.1016/j.talanta.2015.09.064

• Gas diffusion
• Flow analysis
• Pulsed flow
• Constant flow

Considering the beneficial aspects arising from the implementation of pulsed flows in flow analysis, and the relevance of in-line gas diffusion as an analyte separation/concentration step, influence of flow pattern in flow systems with in-line gas diffusion was critically investigated. To this end, constant or pulsed flows delivered by syringe or solenoid pumps were exploited. For each flow pattern, two variants involving different interaction times of the donor with the acceptor streams were studied. In the first one, both the acceptor and donor streams were continuously flowing, whereas in the second one, the acceptor was stopped during the gas diffusion step. Four different volatile species (ammonia, ethanol, carbon dioxide and hydrogen sulfide) were selected as models. For the flow patterns and variants studied, the efficiencies of mass transport in the gas diffusion process were compared, and sensitivity, repeatability, sampling frequency and recorded peak shape were evaluated. Analysis of the results revealed that sensitivity is strongly dependent on the implemented variant, and that flow pattern is an important feature in flow systems with in-line gas diffusion.

• 出版日期2016-2-1