Research Progress on Stable Isotope Analysis Techniques of Hydrogen and Oxygen in Water and Their Influencing Factors

The application of hydrogen and oxygen stable isotope analysis of water in fields including hydrology, geology, and ecology was increasingly expanded. However, significant differences were observed in the analytical methods and effects of samples from different matrices. Compared with the traditional isotope ratio mass spectrometry （IRMS）, isotope ratio infrared spectroscopy （IRIS） was recognized as the preferred method for current hydrogen and oxygen stable isotope analysis of water due to its advantages of rapid analysis, low cost, and simple pretreatment. IRIS achieves precision comparable to IRMS in pure water or simple matrix samples, but significant decreases in analytical precision and accuracy were caused by volatile organic matters when complex samples including oilfield wastewater, landfill leachate, petroleum-contaminated site water, and plant/soil extracts were analyzed. A systematic review of stable isotope analysis techniques of hydrogen and oxygen in water （IRMS and IRIS） was conducted. Their advantages and disadvantages were compared, and the impacts of memory effect and matrix effect on analytical precision were summarized. The problems and countermeasures of high-salinity and high-organic-matter samples analyzed by IRIS technique were focused on, and prospects for future research directions were put forward. This review was intended to provide references for the selection of analytical methods for hydrogen and oxygen stable isotopes in water from different samples and the evaluation of isotope application effects （62 ref. cited）.