Patent ID: 8105837

Claim:
A method for automatic assay of anionic detergents in seawater using an analytical apparatus comprising a flow system for buffer solution, a flow system for color developer solution, a flow system for reference solution, a flow system for samples, a sample valve and a flow system for analysis and detection, wherein the method comprises the following steps: (1) allowing a testing sample (S) to flow along the flow system for samples and into the flow system for analysis and detection, and allowing a reference solution (R ref ) to flow along the flow system for reference solution, then through the sample valve and into the flow system for analysis and detection where the testing sample (S) is mixed with the reference solution (R ref ) to form a first mixture of the testing sample (S) and the reference solution (R ref ), and allowing the first mixture to then flow into an optical flow cell so that a baseline is produced and mapped; (2) allowing the testing sample (S) to flow along the flow system for samples and into the flow system for analysis and detection, and allowing a buffer solution (R 1 ) to flow along the flow system for buffer solution and into the flow system for color developer solution where the buffer solution (R 1 ) is mixed with a color developer solution (R 2 ) to form a second mixture of the buffer solution (R 1 ) and the color developer solution (R 2 ), and allowing the second mixture to then flow through the sample valve and into the flow system for analysis and detection where the testing sample (S) is mixed with the second mixture to form a third mixture of the testing sample (S), the buffer solution (R 1 ) and the color developer solution (R 2 ), and allowing the third mixture to then flow into an optical flow cell so that a spectrogram of the testing sample (S) is produced and mapped; (3) repeating steps (1) and (2) with a series of standard samples having known concentrations of an anionic detergent instead of the testing sample (S) to obtain a series of spectrograms of the standard samples; and (4) comparing the spectrogram of the testing sample (S) with the series of spectrograms of the standard samples to determine the content of the anionic detergents in the testing sample (S); wherein the testing sample (S) is seawater, the buffer solution (R 1 ) is an aqueous solution of potassium biphthalate-hydrochloric acid, the color developer solution (R 2 ) is an aqueous solution of ethyl violet-polyvinyl alcohol, and the reference solution (R ref ) is deionized water.