Techniques for toxic metal detection and speciation in aqueous matrices

A system comprising:

• a vessel to receive an aqueous matrix;
• a source of an oxidizer;
• a source of an acid;
• a measurement subsystem operable to measure concentration of a first form of a target metal;
• a processing subsystem that is to selectively introduce a selected one of oxidizer or acid, from a respective one of the source of the oxidizer and the source of the acid, to a second form of the target metal, the selected one of an oxidizer or an acid operable to convert the second form of the target metal to the first form of the target metal;
• a transfer subsystem to selectively transfer at least the target metal from samples of the aqueous matrix (1) from the vessel to the measurement subsystem, (2) from the vessel to the processing subsystem, and (3) from the processing subsystem to the measurement subsystem;
• and
• a control subsystem to control the transfer subsystem, the processing subsystem, and the measurement subsystem, so as to (a) measure a first concentration of the first form of the target metal in a first one of the samples for which the second form of the target metal has not been converted to the first form of the target metal by introduction of the selected one of an oxidizer or an acid, (b) measure a second concentration of the first form of the target metal in a second one of the samples for which the second form of the target metal has been converted to the first form of the target metal by introduction of the selected one of an oxidizer or an acid, and (c) calculate a third concentration of the second form of the target metal in the aqueous matrix based on a relationship between the first concentration and the second concentration.

A method of operating a system, the system having a vessel to receive an aqueous matrix, a source of at least one of an oxidizer or an acid, a measurement subsystem, a processing subsystem, and a control subsystem, the method comprising:

• causing the processing subsystem to selectively introduce, from the source, the at least one of an oxidizer or an acid to a second form of the target metal, the at least one of an oxidizer or an acid operable to convert the second form of the target metal to the first form of the target metal;
• causing the transfer subsystem to selectively transfer at least the target metal from samples of the aqueous matrix (1) from the vessel to the measurement subsystem, (2) from the vessel to the processing subsystem, and (3) from the processing subsystem to the measurement subsystem;
• and
• causing the control subsystem to control the transfer subsystem, the processing subsystem, and the measurement subsystem, so as to (a) measure a first concentration of the first form of the target metal in a first one of the samples for which the second form of the target metal has not been converted to the first form of the target metal by introduction of the at least one of an oxidizer or an acid, (b) measure a second concentration of the first form of the target metal in a second one of the samples for which the second form of the target metal has been converted to the first form of the target metal by introduction of the at least one of an oxidizer or an acid, and (c) calculate a third concentration of the second form of the target metal in the aqueous matrix based on a relationship between the first concentration and the second concentration.