Validation of Diffusion Tube Method for Calibrating Portable Metal Oxide Semiconductor, Photo-Ionized, and Interference-Enhanced Reflection Volatile Organic Compound Detectors

摘要

The diffusion tube method is a technique for generating single-or multi-component volatile organic compound (VOC) gases. Previously, we verified that standard cylinder gases are effective in preparing calibration gases for portable VOC detectors. In this study, we investigated the validity of the diffusion tube method for evaluating portable VOC detectors, such as metal-oxide semiconductor (MOx) detector, photo-ionized detector (PID), and interference-enhanced reflection (IER) detector. The deviations between gas concentrations evaluated by the VOC detectors when the calibration gas generated by the diffusion tube method was compared with that of the same composition generated by the standard gas cylinder method were 2.7%, -0.30%, and 8.3% for the MOx, PID, and IER detectors, respectively. These deviations, which are far below the acceptable tolerance level of the detectors (around ±20%), verify that the diffusion tube method is an effective calibration method for the three detectors.