Research on the FAIMS System Based on Multijet DBD Ion Source and Background Noise Suppression

This study designs and constructs a dielectric barrier discharge (DBD)-field asymmetric ion mobility spectrometry (FAIMS) system. An innovative approach is adopted to fabricate a multi-channel DBD ion source using 3D printing technology. The printing material itself served as the discharge medium, enabling the simultaneous generation of four plasma jets, effectively enhancing the ionization efficiency. By optimizing the inlet positions of nitrogen and helium gases, the background ion signal intensity was reduced from 356.3 pA to 0, effectively eliminating the system background noise. Under the optimal working conditions, namely when the four-stream ion source operates at a helium gas flow rate of 0.5 L/min, a discharge voltage of -5.1 kV, and a nitrogen gas flow rate of 1.2 L/min, the detection sensitivity of FAIMS was significantly improved compared to the single-stream source. The nonlinear coefficient α curve characteristics of the FAIMS spectrum were utilized to distinguish different samples. As a validation of the application prospect, exhaled gas samples from diabetic patients and healthy volunteers were collected and analyzed. The results showed that the characteristic signal intensity of acetone in the exhaled gas of diabetic patients was higher than that of healthy controls, and when the blood glucose level was 2.5 mmol/L higher, the signal intensity was approximately 0.25 times higher. This preliminary study proves the potential of this system in non-invasive screening of diabetes.