Terahertz Absorption Characteristics of Ammonium Salt Solution Based on Self-Sampling Microfluidic Chip

In this study, a sandwich terahertz microfluidic chip with high transmission to terahertz wave was designed. The terahertz transmission spectra of distilled water, 0.9 mol/L NH
4
Cl, (NH
4
)
2
SO
4
, (NH
4
)
2
CO
3
and CH
3
COONH
4
were measured by combining the chip with terahertz technology. The experimental results show that at the same concentration, the THz spectra of different ammonium salt solutions are obviously different, which indicates that the hydration process of ions has an effect on the hydrogen bond between water molecules, and is reflected in the terahertz transmission spectrum.