测量气体样品的红外光谱时, 红外光谱仪器内的水汽和气体样品中所含的水汽会严重干扰气体的红外光谱。 为消除水汽的干扰, 通常作法是测量前必须将水分子(气态)彻底排除掉, 也就是使光谱仪器和气体样品保持干燥状态。 该研究提供一个新测量方法, 不需任何干燥预处理过程, 直接获得含水汽的丙酮气体的红外光谱。 经过几十次光谱扫描累加后, 观察并根据水汽谱的吸收峰性质(吸光率>0或吸光率<0), 向光谱仪样品室引入少量干燥氮气或少量潮湿空气, 在接下来的光谱扫描累加过程中, 水汽吸收峰将逐渐变小直至消失。 实验结果表明该方法去除水汽干扰峰简单高效。 新方法在0.5 cm-1光谱分辨率时效果非常好, 为气体的高分辨分析提供了有力工具。

Water vapor in the beam of a Fourier transform infrared (FTIR) spectrometer or/and in a gas cell is a major source of interference in the infrared measurement of a gas sample. In general, in order to eliminate the effect of water vapor, we have to completely remove these molecules before the measurement of any spectrum. Herein, we provide an approach to collect an IR spectrum of a gas (wet acetone) sample free from water vapor interference without any drying pretreatment. After dozens of scans, the air atmosphere in the sample compartment of the FTIR spectrometer will be slightly adjusted by small amounts of dry air or wet air (room air) depending on the property of water vapor lines (absorbance>0 or absorbance <0). Water vapor lines will then gradually disappear when the ensuing collection process is continued. The experiment results demonstrated that this method is a facile and very effective way to remove water vapor interference. Moreover, this method works still well for the measurement at 0.5 cm-1 resolution, typically used in the gas infrared measurement.