Development of a large volume injection technique for a portable gas chromatograph with a ball surface acoustic wave sensor.
Takamitsu Iwaya, Koya Yamawaki, Shingo Akao, Kentaro Shirai, Kazushi Yamanaka
The Review of scientific instruments February 1, 2026 DOI: 10.1063/5.0302681 (opens in new tab) via PubMed
Summary
AI-generated from the abstractA large volume injection technique was developed for portable gas chromatographs, enabling liquid sample analysis with volumes up to 50 μl without loss of analyte. Using a compact device with a spherical surface acoustic wave sensor, linear response to sample volume was confirmed with linear alkanes. For drug analysis, a detection limit of about 23 ng/ml for a hallucinogen simulant in urine was achieved, well below the 250 ng/ml cutoff for MDMA. A correlation between sensor response and retention index was also found, suggesting potential for quantitative analysis.
Study at a glance
| Characteristics | Experimental study Peer reviewed |
|---|---|
| Population | Linear alkanes with 7-13 carbons in pentane solvent; 1,2-methylenedioxybenzene in urine |
| Intervention | large volume injection technique |
| Key finding | A large volume injection technique for portable gas chromatographs achieved a detection limit of about 23 ng/ml for a hallucinogen simulant in urine, below the MDMA cutoff of 250 ng/ml. |
Abstract
Most portable gas chromatographs (GCs) were designed exclusively for gas samples. If they can handle liquid samples too, the range of application is expected to expand substantially. However, in general, the injection volume of liquid samples in GCs is limited to about 1 μl or less to prevent the loss of analytical precision and instrument contamination. Therefore, it is difficult to achieve sufficient sensitivity with the limited resources of the portable GCs. In this study, we developed a large volume injection (LVI) technique applicable to portable GCs, fabricated a compact LVI-GC using a spherical surface acoustic wave (SAW) sensor (the ball SAW sensor) as the detector, and confirmed its basic operation. Using a sample mixture of linear alkanes with 7-13 carbons in a pentane solvent, we evaluated measurement conditions without the loss of analyte in a sample volume range of ∼5-50 μl and confirmed the linearity of the response with respect to the sample volume. In addition, 1,2-methylenedioxybenzene, a simulant of a hallucinogen, 3,4-methylenedioxymethamphetamine (MDMA), was analyzed for an application in drug analysis in urine, and a detection limit of ∼23 ng/ml, well below the cutoff value of ∼250 ng/ml for MDMA, was achieved. Furthermore, we found a correlation between the response of the ball SAW sensor and the retention index and investigated the possibility of quantitative analysis using retention indices.