Direct injection for high sample throughput capillary gas chromatographic-mass spectrometric bioanalysis

Area of Science:

• Analytical Chemistry
• Biochemistry
• Pharmacokinetics

Background:

• Temperature-programmed splitless injection capillary gas chromatography-mass spectrometry (GC-MS) is a common technique for quantitative bioanalysis.
• This method is associated with long analysis times, limiting sample throughput in high-volume laboratories.

Purpose of the Study:

• To investigate isothermal direct injection capillary GC-MS as a faster alternative for quantitative bioanalysis.
• To compare the performance of direct injection with the traditional splitless injection method.

Main Methods:

• Quantitative bioanalysis using capillary gas chromatography-mass spectrometry (GC-MS).
• Comparison of isothermal direct injection versus temperature-programmed splitless injection techniques.
• Analysis of spiked plasma samples to assess chromatographic quality, run time, sensitivity, and performance parameters.

Main Results:

• Direct injection achieved high-quality chromatography with significantly shorter run times compared to splitless injection.
• Sensitivity and overall performance parameters of direct injection were comparable or superior to splitless injection.
• The direct injection method demonstrated potential for increased sample throughput.

Conclusions:

• Isothermal direct injection capillary GC-MS is a viable and efficient alternative to splitless injection for quantitative bioanalysis.
• Replacing splitless injection with direct injection can significantly improve sample throughput in bioanalytical laboratories.
• Direct injection is recommended for trace-level GC-MS bioanalytical methods when feasible.