Dataset: Dissolved Trace Metals
Deployment: KM1128

Seawater sampling occurred during October 1-25 2011 onboard the R/V Kilo Moana during the METZYME expedition (Saito et al., 2014). Seawater samples for trace metal analyses were collected using a trace metal clean rosette consisting of X-Niskins on a trace metal clean (Amsteel) winch line. Following seawater collection, X-Niskins were brought into a fabricated shipboard class-100 clean room and pressurized with filtered high purity nitrogen gas. Seawater was filtered through 47mm 0.2 µm Supor membranes to remove the particulate fraction.

METZYME seawater was acidified to pH 1.8 using hydrochloric acid (Optima grade, Fisher Chemical). Seawater preconcentration was performed using an automated solid phase extraction system, seaFAST pico, run in offline concentration mode.  Following offline seaFAST preconcentration, the multi-element quantitative analysis was performed using an iCAP Q inductively coupled plasma-mass spectrometer (ICP-MS) (Thermo Scientific). Concentrations of Fe, Mn, Zn Ni and Cd were determined using a six-point external standard curve with a multi-element standard (SPEX CertiPrep), diluted to range from 1-10 ppb in 5% nitric acid. Indium standards (SPEX CertiPrep) were similarly added to these standard stocks, diluted to 1, 2, 3, 4 and 10ppb. Instrument injection blanks consisted of 5% nitric acid in Milli-Q. Standard curve R² values were ≥0.98 for the metals monitored.