开放光程傅里叶变换红外光谱（OP-FTIR）可以实现快速、 灵活、 定量化地探测气体, 但相较于气体池抽取气体的方式, OP-FTIR的信号微弱, 对气体的探测能力受到制约, 为提高其对气体的探测能力, 以自然状态的气体流动为扰动对测得的气体红外光谱数据进行二维相关分析。 以乙醇气体和两种白酒挥发物作为验证对象, 用OP-FTIR方法测得乙醇气体以及泸州特酿和汾酒挥发物的红外吸收光谱。 未经处理的乙醇气体红外吸收光谱图中, 并没有观察到明显的乙醇特征峰, 对该红外吸收光谱数据进行二维相关分析, 其二维相关同步谱图中对角线上（1 050, 1 050 cm-1）处有明显的自相关峰, 该自相关峰来自于乙醇, 结果验证了: 结合二维相关红外光谱, 提高了OP-FTIR方法对气体的探测能力。 对不同浓度乙醇气体的红外吸收光谱数据进行二维同步相关处理, 发现二维相关同步谱图中以1 050 cm-1 为中心的自相关峰强度随着乙醇气体浓度的增加而增强, 说明基于二维相关光谱的OP-FTIR气体探测方法具有一定的定量分析能力。 用OP-FTIR方法探测泸州特酿和汾酒的挥发物时, 在820～1 480 cm-1波段探测挥发物中的乙醇气体, 气体含量通过二维相关同步谱图中对角线上（1 050, 1 050 cm-1）处的自相关峰强度来衡量, 结果显示泸州特酿挥发物中的乙醇气体含量高于汾酒; 在1 700～1 820和1 400～1 600 cm-1波段探测挥发物中的香气物质, 通过对比泸州特酿和汾酒挥发物的二维相关异步谱图, 发现泸州特酿比汾酒挥发物二维相关异步谱图中有更多的交叉峰, 说明泸州特酿挥发物表现出更丰富的香气物质信息, 这一区别可以用来鉴别泸州特酿和汾酒挥发物。 研究证明, 基于二维相关红外光谱的OP-FTIR气体探测方法, 提高了OP-FTIR方法探测气体的能力, 且具有一定的定量分析能力, 同时, 用于不同挥发物的鉴别也值得进一步研究。

Open-Path Fourier Transform infrared spectroscopy (OP-FTIR) enables fast, flexible, and quantitative detection of gas, but OP-FTIR signal is weak compared to gas pool extraction methods, and its ability to detect gas is restricted. In order to improve its detecting capacity of gas, two-dimensional correlation analysis is performed on the measured infrared spectrum data of the gas with natural gas flow disturbance. The ethanol gas and two kinds of Chinese spirits’ volatiles were used as the verification objects. The infrared absorption spectra of ethanol gas and the volatiles of Luzhouteniang and Fenjiu were measured by OP-FTIR method. In the untreated infrared absorption spectrum of ethanol gas, no obvious characteristic peak of ethanol was observed. The two-dimensional correlation analysis of the infrared absorption spectrum data showed that there was an obvious autopeak centered at 1 050 cm-1 in the two-dimensional correlation synchronous spectrum, and the autopeak came from ethanol. The results verified that the gas detection ability of the OP-FTIR method which is combined with two-dimensional correlation infrared spectroscopy was improved. The infrared absorption spectrum data of different concentrations of ethanol gas were processed by synchronous two-dimensional correlation. It was found that the autopeak intensity centered at 1 050 cm-1 in the two-dimensional correlation synchronous spectrum increased with the increase of ethanol gas concentration, indicating that OP-FTIR gas detection method based on two-dimensional correlation spectrum has a certain quantitative analysis capability. When detecting the volatiles of Luzhouteniang and Fenjiu by OP-FTIR method, the ethanol gas in the volatile matter was detected in the region of 820～1 480 cm-1, and the gas content was measured by the intensity of the auto peak at (1 050, 1 050 cm-1) in the two-dimensional correlation synchronous spectrum. The results showed that the ethanol gas content in the volatiles of the Luzhouteniang is higher than that in Fenjiu; the aroma components in the volatile matter were detected by the region of 1 700～1 820 and 1 400～1 600 cm-1, by comparing the two-dimensional asynchronous spectrum of the volatiles of the Luzhouteniang and Fenjiu, it found that there are more cross peaks in the two-dimensional asynchronous spectrum of the volatiles of Luzhouteniang, so Luzhouteniang showed more abundant aroma substances information compared to the volatiles of Fenjiu, this difference can be used to identify the volatiles of Fenjiu and Luzhouteniang. The research proved that the OP-FTIR gas detection method based on two-dimensional correlation infrared spectroscopy realized the improvement of the gas detection ability of OP-FTIR method, and has certain quantitative analysis ability. At the same time, combined with two-dimensional correlation infrared spectroscopy, OP-FTIR also has further research significance for identifying different volatile matter.