M. Fillet et al., Separation of nonsteroidal anti-inflammatory drugs by capillary electrophoresis using nonaqueous electrolytes, ELECTROPHOR, 20(9), 1999, pp. 1907-1915
The aim of the present work was to investigate the separation of nonsteroid
al antiinflammatory drugs (NSAIDs: niflumic acid, flufenamic acid, piroxica
m, alclofenac, tiaprofenic acid, flurbiprofen, suprofen, ketoprofen, naprox
en, indomethacin, carprofen, indoprofen, sulindac) in capillary electrophor
esis (CE) using completely nonaqueous systems. The influence of different p
arameters such as nature and proportion of organic solvent (methanol, aceto
nitrile, 2-propanol), apparent pH (ranging from 7 to 9) and temperature (ra
nging from 25 to 40 degrees C) on selectivity and migration times were stud
ied systematically in an uncoated fused-silica capillary. A nonaqueous elec
trolyte made of 50 mM ammonium acetate -13.75 mM ammonia in methanol proved
to resolve 11 NSAIDs at 25 degrees C and 13 NSAIDs at 36 degrees C, both w
ithin 13 min and without a modifier besides the methanol itself. The same b
uffer containing 30% acetonitrile provides a satisfactory separation for 13
NSAIDs within 14 min at 25 degrees C.