Back to Search Start Over

A dynamic liquid–liquid interfacial pressure detector for the rapid analysis of surfactants in a flowing organic liquid

Authors :
Jaroon Jakmunee
Yuthapong Udnan
Sumalee Tanikkul
Bryan J. Prazen
Robert E. Synovec
Kate Grudpan
Narong Lenghor
Bethany A. Staggemeier
Mazen L. Hamad
Source :
Talanta. 65:722-729
Publication Year :
2005
Publisher :
Elsevier BV, 2005.

Abstract

Design and development of a dynamic interfacial pressure detector (DIPD) is reported. The DIPD measures the differential pressure as a function of time across the liquid-liquid interface of organic liquid drops (i.e., n-hexane) that repeatedly grow in water at the end of a capillary tip. Using a calibration technique based on the Young-Laplace equation, the differential pressure signal is converted, in real-time, to a relative interfacial pressure. This allows the DIPD to monitor the interfacial tension of surface active species at liquid-liquid interfaces in flow-based analytical techniques, such as flow injection analysis (FIA), sequential injection analysis (SIA) and high performance liquid chromatography (HPLC). The DIPD is similar in principle to the dynamic surface tension detector (DSTD), which monitors the surface tension at the air-liquid interface. In this report, the interfacial pressure at the hexane-water interface was monitored as analytes in the hexane phase diffused to and arranged at the hexane-water interface. The DIPD was combined with FIA to analytically measure the interfacial properties of cholesterol and Brij((R))30 at the hexane-water interface. Results show that both cholesterol and Brij((R))30 exhibit a dynamic interfacial pressure signal during hexane drop growth. A calibration curve demonstrates that the relative interfacial pressure of cholesterol in hexane increases as the cholesterol concentration increases from 100 to 10,000mugml(-1). An example of the utility of the DIPD as a selective detector for a chromatographic separation of interface-active species is also presented in the analysis of cholesterol in egg yolk by normal-phase HPLC-DIPD.

Details

ISSN :
00399140
Volume :
65
Database :
OpenAIRE
Journal :
Talanta
Accession number :
edsair.doi.dedup.....1118ff0786205ae288c2685ea435d30b
Full Text :
https://doi.org/10.1016/j.talanta.2004.07.040