An advanced commercial InfraRed Isotope Ratio (IR2) analyzer has been developed in Arrow Grand Technologies and the hollow waveguide (HWG) is used as the sample tube. By measuring the selected CO2 absorption peaks in the Mid- IR(MIR), the stable carbon isotope ratio, i.e. 13C, is obtained at a fast sampling rate. Combined with a GC and a combustor, it has been successfully employed to measure compound specific 13C isotope ratios in the field. By updating the single path HWG to 5-path HWG, we have also demonstrated its application for the environmental and health research. Here, the isotope ratio analyzer is minimized in size and weight to better fulfill the field deployment requirements. The size is reduced from 80cm*51cm*51cm to 74cm*33cm*46cm. After optimizing all subsystems, the minimized isotope ratio analyzer has a better performance. What’s more, the number of HWG paths can be selected to match the specific application. For instance, a 3-pass HWG is selected to conduct ultra-sensitive compound specific isotope analysis for mud gas logging, and a 5+1 pass HWG could measure isotope ratios of carbon with an ultra-broad CO2 concentration range of 300 ppm-47,500 ppm and a fast sample refresh and data processing rate up to 10Hz.