PMID- 17676757
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20071025
LR  - 20070831
IS  - 0003-2700 (Print)
IS  - 0003-2700 (Linking)
VI  - 79
IP  - 17
DP  - 2007 Sep 1
TI  - Electrophoretic effects of the adsorption of anionic surfactants to 
      poly(dimethylsiloxane)-coated capillaries.
PG  - 6675-81
AB  - Poly(dimethylsiloxane) (PDMS) is one of the most convenient materials to 
      construct capillary electrophoresis microchips. Even though PDMS has many 
      advantages, its use is often limited by its hydrophobicity. Although it is 
      well-known that the surface properties of PDMS can be modified by anionic 
      surfactants, very little is known regarding the driving forces or the 
      electrophoretic consequences of the adsorption of anionic surfactants. In this 
      work, the adsorption of alkyl surfactants on PDMS was studied by performing 
      electroosmotic flow (microEOF) measurements. In order to mimic the behavior of 
      PDMS microchannels, fused-silica capillaries were coated with PDMS and used for 
      the microEOF measurements. This approach allowed using standard CE 
      instrumentation and provided significant advantages over similar experiments 
      performed on microchips. The change in the microEOF in the presence of 
      surfactants was correlated to the surfactant adsorbed amount which, plotted 
      versus surfactant concentration, gives an adsorption isotherm. The adsorption 
      isotherms were obtained using alkyl surfactants with different chain lengths and 
      head groups. According to our results, the interaction of alkyl surfactants with 
      the PDMS surface is determined by a combination of hydrophobic and electrostatic 
      interactions, where the former is more significant than the latter. The affinity 
      of each surfactant for the PDMS surface was calculated by fitting the adsorption 
      profiles with a Langmuir equation and, in the case of single-charged surfactants, 
      correlated to the corresponding cmc value.
FAU - Mora, Maria F
AU  - Mora MF
AD  - Department of Chemistry, The University of Texas at San Antonio, San Antonio, TX 
      78249, USA.
FAU - Giacomelli, Carla E
AU  - Giacomelli CE
FAU - Garcia, Carlos D
AU  - Garcia CD
LA  - eng
PT  - Journal Article
DEP - 20070803
PL  - United States
TA  - Anal Chem
JT  - Analytical chemistry
JID - 0370536
EDAT- 2007/08/07 09:00
MHDA- 2007/08/07 09:01
CRDT- 2007/08/07 09:00
PHST- 2007/08/07 09:00 [pubmed]
PHST- 2007/08/07 09:01 [medline]
PHST- 2007/08/07 09:00 [entrez]
AID - 10.1021/ac070953g [doi]
PST - ppublish
SO  - Anal Chem. 2007 Sep 1;79(17):6675-81. doi: 10.1021/ac070953g. Epub 2007 Aug 3.