Trace-metal-clean protocols

As described by Sedwick et al. (this issue), a semicontinuous culture of the Ross Sea P. antarctica strain was successively diluted with low-iron (<0.2 nM dissolved Fe) filtered Ross Sea seawater, over a period of several weeks, using a rigorous trace-metal-clean protocol. Using this process, we obtained an inoculum culture of colonial P. antarctica in LI medium diluted 9,140-fold with filtered, low-iron (0.17 nM dissolved Fe) Ross Sea seawater, for which we calculate dissolved Fe and EDTA concentrations of 1.42 nM and 1.25 nM, respectively. Prior to commencing... 

Eleven days before commencing the experiment, 50 ml of this culture was diluted to 1 1 with 0.2 pm-filtered station B seawater in an acid-cleaned polycarbonate bottle, using a stringent trace-metal clean protocol. A peristaltic pump was used to transfer the Station B seawater from the 125-1 polyethylene barrel (in which it had been stored since collection) through acid-cleaned silicone tubing and an acid-rinsed... 

Establishing the protocol to standardize the cleaning of containers according to the sample, type of material and chemical characterization to be effected was seen as critical. The following procedure illustrates the protocol for the cleaning of LPDE bottles for the analysis of trace metals ... 

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