Stable Isotope Laboratory The University of Maine Stable Isotope Laboratory (SIL) has equipment for automated isotopic analysis of water, carbonates, inorganic sulfates, and organic material. These facilities include: Two Picarro L-2130-i laser cavity ring-down spectrometers for analysis of d18O (0.1‰ precision) and dD (0.1‰ precision) of water; Micromass Isoprime dual-inlet MS, with Eurovector elemental analyzer