Chromatographic Behavior of Cationic and Nonionic Surfactants on Silica Gel Impregnated with Paraffin Oil Using Aqueous Formamide Mobile Phase Systems
Ali Mohammad* and Shumaila Khatoon
Analytical Research Laboratory, Department of Applied Chemistry, Faculty
of Engineering and Technology,
Aligarh Muslim University, Aligarh-202002 (INDIA)
* Corresponding author: E-mail:
mohammadali4u@rediffmail.com
Abstract
The migration behavior of cationic and nonionic surfactants on silica gel
impregnated with paraffin oil, tertiary butyl phosphate and silicon oil using
aqueous dimethyl formamide (DMF) was examined. The mobility of surfactants at
different concentration levels of DMF in double distilled water was investigated
on silica gel impregnated with 1% paraffin oil. The most suitable mobile phase
for the mutual separation of cationic and nonionic surfactants was the mixture
of DMF and double distilled water in 6:4 ratios. The separation of
cetylpyridinium chloride (CPC) from Brij-35 was successfully achieved on silica
gel impregnated with 1% paraffin oil. The mobility pattern of cationic as well
as nonionic surfactants on silica gel impregnated with (1, 3, 5, 7 and 10%)
paraffin oil, 1% tertiary butyl phosphate and 1% silicon oil was examined. The
solvent effect on the RF values of surfactants, with protic solvent (DMF
and tetrahydrofuran i.e. THF) and aprotic (Dimethylsulfoxide i.e. DMSO) was
performed on silica gel impregnated with 1% paraffin oil. The migration behavior
of surfactants on stationary phases (alumina, kieselguhr and cellulose)
impregnated with 1% paraffin oil was also studied. The results show reasonable
reproducibility (RF values differ by a factor of 10%). The limits of
detection of CPC and BJ-35 were 0.73 and 0.75 μg respectively. To widen the
applicability of the method, separation of CPC and BJ-35 from a sample of fabric
softener was also investigated. The influence of metal cations as well as
anionic impurities in the separation of CPC and Brij-35 was also examined.
Keywords: TLC, silica gel, paraffin oil, surfactants, dimethyl formamide