Development of a new device for CO2 microdiffusion analysis of fluid samples from volcanic areas without using a fixative

Abstract We propose a new reaction device for the microdiffusion analysis of CO 2 in fluid samples from volcanic areas to improve the conventional analysis procedure, which requires a fixative and good handling skills. To accomplish this, a small resin reaction cell for the sample solution and acid (initiator for CO 2 liberation) was devised and placed in a commercially available air-tight glass container with a Petri dish to form a microdiffusion analysis unit. The analysis was based on the principles of the conventional manual titration method that uses Ba(OH) 2 as the CO 2 absorbent. Using the new device, 99.5% recovery, with a relative standard deviation of 4.5% (n = 8), was achieved in a test analysis for 0.03 mmol of CO 2 liberated from a Na 2 CO 3 solution as a simulated sample. The analytical performance of the new device was almost comparable to that of conventional units under the experimental conditions of this study. Applying this new device for analyzing fluid samples from volcanic areas will contribute to enhancing the performance by reducing the possibility of CO 2 contamination and by simplifying the process by eliminating the need for preparatory cleaning for fixative application. Graphical Abstract