Particulate cysteine and glutathione in the western North Pacific

This repository contains data on particulate cysteine and glutathione distributions in the western North Pacific, collected during the KH-22-7 and KH-23-2 cruises onboard R/V Hakuho Maru from June to September 2022 (legs 1 and 2) and from June to July 2023 (leg 3). Sampling was carried out along the GEOTRACES meridional transect GP22. Samples were collected from the upper 100 m and at the chlorophyll maximum layer using acid-cleaned Niskin X sampling bottles (Obata et al., 2017) mounted on a Conductivity-Temperature-Depth (CTD) carousel, under trace-metal clean conditions in accordance with the GEOTRACES protocol.  Particulate samples were collected byfiltering through GF/F filters (0.7 µm pore size) using an acid-cleaned polycarbonate filtration unit (Sartorius), under gentle negative pressure to prevent cell rupture. The filters were then placed in sample tubes containing a DTPA extraction buffer and stored at -20°C until analysis. Cysteine and glutathione in the samples were derivatized using monobromobimane, separated using high performance liquid chromatography, and detected using a fluorescence detector.