Patent ID: 7923259

Claim:
A method for sampling one or more analytes of a soil sample, comprising: (a) extracting the one or more analytes from the soil sample to generate a liquid sample; (b) passing the liquid sample through one or more pre-concentration chromatographic columns, thereby retaining said one or more analytes on the one or more pre-concentration chromatographic columns and concentrating said one or more analytes; (c) delivering a solvent to the one or more pre-concentration chromatographic columns, thereby eluting said one or more analytes from the one or more pre- concentration chromatographic columns to give an eluate; (d) passing the eluate through one or more analytical chromatographic columns, thereby separating said one or more analytes; and (e) analyzing the separated one or more analytes in a variable wavelength detector and then a photo-assisted electrochemical detector, wherein the two detectors function in-line together, and wherein the lower limit of detection of the one or more analytes achieved electrochemically is about 10 to about 1000 times less than those achieved by the variable wavelength detector.