The capillary gap sampler, a new microfluidic platform for direct coupling of automated solid-phase microextraction...

Area of Science:

• Analytical Chemistry
• Biochemistry

Background:

• Solid-phase microextraction (SPME) coupled with mass spectrometry (MS) is a powerful analytical technique.
• Existing methods can be time-consuming and require larger sample volumes.

Purpose of the Study:

• To introduce a new technology for rapid, automated coupling of SPME and MS.
• To evaluate the performance of a capillary gap sampler for automated SPME and direct analyte delivery to MS.

Main Methods:

• Development and optimization of a capillary gap sampler for automated SPME.
• Coupling the sampler to a mass spectrometer for direct analysis.
• Systematic optimization for stability, reusability, and repeatability.
• Analysis of diazepam, oxazepam, and nordiazepam in human plasma.

Main Results:

• The capillary gap sampler enables quick, automated, and site-specific extraction from low-volume samples.
• High stability, reusability, and repeatability were achieved.
• Successful extraction of benzodiazepines from human plasma with a limit of detection of 0.3 μg/mL.
• A linear dynamic range from 1 to 1000 ng/mL was established for the analytes.
• Relative standard deviation for 20 extractions ranged from 11% to 17%, indicating acceptable repeatability.

Conclusions:

• The capillary gap sampler offers significant advantages for automated SPME-MS analysis.
• The technology is suitable for analyzing benzodiazepines in human plasma within the therapeutic range.
• The method is robust, repeatable, and efficient for trace-level analysis.