Indirect laser-induced fluorescence detection for capillary electrophoresis using a violet diode laser

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Separation Science

Background:

• Indirect laser-induced fluorescence (LIF) is a sensitive detection method.
• Capillary electrophoresis (CE) is a powerful separation technique.
• Detection of chemical warfare agent (CWA) degradation products is crucial for security.

Purpose of the Study:

• To evaluate the use of a violet (415 nm) diode laser for indirect LIF detection in CE.
• To determine the detection limits for inorganic anions and CWA degradation products.
• To compare the performance with existing detection methods.

Main Methods:

• Capillary electrophoresis separations were performed using a violet diode laser for indirect LIF detection.
• Inorganic anions were detected using 8-hydroxypyrene-1,3,6-trisulfonic acid as the indirect probe.
• CWA degradation products were detected using tetrakis(4-sulfophenyl)porphine as the indirect probe.

Main Results:

• Submicromolar detection limits (40-80 ppb) were achieved for inorganic anions in 2-min separations.
• Detection limits of 0.1 microM (9 ppb) were achieved for CWA degradation products, an order of magnitude better than indirect UV detection.
• Excellent baseline stability was observed with dynamic reserve (DR) values > 1000, 15 times better than unstabilized HeCd laser.

Conclusions:

• Violet diode laser indirect LIF is a highly sensitive and stable detection method for CE.
• This technique provides significant improvements in detection limits for CWA degradation products.
• The method is suitable for rapid analysis of both inorganic anions and CWA degradation products.