XAS spectroscopy, sulfur, and the brew within blood cells from Ascidia ceratodes

Sulfur within living Ascidia ceratodes blood cells was speciated using K-edge X-ray absorption spectroscopy (XAS). This study marks the first use of K-edge XAS to determine vacuolar pH and cytosolic emf. Functionality included: thiol-disulfide (~ 12%), sulfate mono- and diesters (~ 36%), and 5-8% mono- and dibenzothiophene, thiadiazine, and epi-sulfide.