The recently acquired 253 mass spectrometer is specifically configured for triple oxygen isotope analysis, with narrow cups aligned for masses 32, 33, and 34. Two extraction lines are connected to this instrument. The first is a 'conventional' laser fluorination line for milligram-sized samples. It is equipped with a GC column to purify the O2 gas, which is then admitted into a dual inlet system for the highest possible precision. The second extraction line is a low-blank micro line that is for microgram-sized samples. Samples are admitted through a GasBench interface and run in continuous flow mode. Samples can be cut out of thick sections (100 micron thickness) using a 213 nm UV laser system.