Deuterium (also referred to as hydrogen-2, symbol D or 2H) is a natural, stable isotope of hydrogen with a nucleus containing one proton and one neutron. δD analysis, also referred to as an isotopic signature, is used in conjunction with δ18O analysis to determine the V-SMOW (Vienna Standard Mean Ocean Water) value of water (H2O) molecules. δD measurements can help inform ecology, hydrology, and paleontology studies.
Variations of δD and δ18O compositions in water are caused by isotope effects in the hydrological cycle due to isotope fractionation at all kind of phase transformation: evaporation, condensation, and others. Basically, the isotope fractionation is dependent of temperature. Therefore, δD and δ18O analysis from groundwater or ice core samples can be used to gain conclusions about the climatic conditions during groundwater recharge.
Picarro has designed and produced several isotope analyzers that precisely measure δD in water for laboratory and field studies.
Picarro L2130-i 同位素分析仪可实现水稳定同位素的高质量测量，适用于古气候学、水文学和海洋学等严苛应用。运用各种 Picarro 外围设备，可以对取自液体、气体和固体的水样品进行 δ18O 和 δD 高精度测量。
Picarro L2140-i 水同位素分析仪可同步测量固体、液体和气体中的 δ18O、δ17O 和 δD。此外，这款分析仪还可以亚 15 ppb (<0.015‰) 的精度测定 17O-盈余。将 17O-盈余的测量与 δ18O 和 δD的高精度测量相结合，地球科学家们能够增强我们对现今气候以及水圈与生物圈之间相互作用的理解，并帮助人们重建过往气候条件。