High-sensitivity determination of the degradation products of chemical warfare agents by capillary electrophoresis-indirect UV absorbance detection.
Capillary electrophoresis coupled with indirect UV absorbance detection was employed for the determination of the chemical warfare agent degradation products: methylphosphonic acid, ethyl methylphosphonate, isopropyl methylphosphonate, and pinacolyl methylphosphonate. Glutamic acid was used as a buffering agent at its isoelectric point (pH 3.22). In its zwitterionic form, glutamic acid does not act as a competing co-anion in the system, thus providing buffering capacity while maintaining high sensitivity. The indirect probe (phenylphosphonic acid) concentration was lowered to 1 mM from the 10 mM in previous literature studies, further enhancing sensitivity. Detection limits of 2 microM were achieved with hydrodynamic injection and up to 100-fold lower using electrokinetic injection. The increased buffering capacity of this system over previous methods led to migration time reproducibility RSD values of 0.18 to 0.22%. This represents a 10-fold improvement in reproducibility over previous studies with comparable or improved sensitivity.
Melanson
J E
JE
Department of Chemistry, University of Alberta, Edmonton, Canada.
Wong
B L
BL
Boulet
C A
CA
Lucy
C A
CA
D002021:Buffers; D002138:Calibration; D002619:Chemical Warfare Agents / Q000737:chemistry*; D019075:Electrophoresis, Capillary / Q000379:methods*; D006868:Hydrolysis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013056:Spectrophotometry, Ultraviolet
D002021:Buffers; D002619:Chemical Warfare Agents