Development of a Computer Controlled Trace Metal Preconcentrator. 1. System Description and Design.
RHODE ISLAND UNIV KINGSTON GRADUATE SCHOOL OF OCEANOGRAPHY
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This report describes the design principles, detailed circuit diagram, and software for a multiple sample automated preconcentrator MSAP. The MSAP is designed to accept up to 12 samples of seawater. It can be expanded to a 24-sample system without major modification of the circuit design. The overall system includes sample bottles containing approximately 250 ml of seawater that flows through a chromatographic cartridge which extracts dissolved transition and heavy metals. The metals that are loaded on the cartridge are eluted with about 7 ml of a 2 N HC1-0.1 N HN03 mixture. The acid medium with the metals is injected into a graphite furnace for analysis. Nearly all components of the flow system are constructed on Teflon to avoid contamination. Provisions are made to wash the extraction cartridge at appropriate times and to precondition it between samples. Fluid flow through the system is controlled by nitrogen gas pressure at 5-15 psi using a series of two-way and three-way solenoid valves that are controlled by a CBM 4016 microcomputer. The system will be described in terms of a typical operation cycle. The system consists of 12 sample modules, three types of cartridge elution media, and the nitrogen pressure system.
- Physical and Dynamic Oceanography
- Computer Programming and Software
- Test Facilities, Equipment and Methods