High temperature hydrothermal fluids are collected by the Deep-sea Autonomous and automated Fluid Sampler (DEAFS). The instrument is deployed at the footstep of the Montsegur edifice. The site, named Montserrat, expels hydrothermal fluid at 312°C which were collected beforehand by gas-tight fluid sampler manipulated and triggered by the hydraulic arm of the submarine vehicle (ROV Victor). Several chemical analyses are performed aboard the research vessel: such as salinity and d20/20 by refractometer, pH and Eh by electrode (pH standard 4.01 and 7; Eh standard solution at -220mV), H2S and total S concentrations measured by electrode (AquaMS, amperometric method) at measured pH value. Two i-button temperature sensors have been encapsulated in a titanium housing and attached on the instrument. The sensors have been sequenced for temperature measurement every 12h. The DEAFS has performed a full sample collection sequence starting on the 23/06/2022 till the 25/04/2023. Regional Node: EMSO-Azores, Lucky Strike Hydrothermal Field Vent field : Montserrat at the base of Montsegur Latitude : 37º17.2744’N Longitude : 32º16.5461’W Depth : 1699 m