Reston stable isotope lab (RSIL): reference caps

Photo of silver capsules containing reference water used for the calibration of stable hydrogen and oxygen measurements. This reference material is intended for calibration of stable hydrogen (δ²H) and oxygen (δ¹⁸O) measurements of unknown water or hydrogen- or oxygen-bearing substances with a TC/EA (thermal conversion/elemental analyzer) and an isotope-ratio mass spectrometer by quantifying drift with time and isotope-ratio-scale contraction. These capsults contain 0.15 or 0.25 µL of VSMOW2 (Vienna Standard Mean Ocean Water 2) or SLAP2 (Standard Light Antarctic Precipitation 2) reference water sealed in a silver tube.