Embodiments of the present specification provide methods and systems for clearing a detector of contaminants or any other undesirable substances that may affect operation of detector. The methods and systems enable a clear-down mode to clear the detector after an alarm is detected during sampling by the detector. The clear-down mode may be enabled immediately upon detecting a substance of interest. Further, the clear-down mode is effective to increase and direct all air flow through the detector in order to maximally purge contaminants from the detector.

Embodiments of the present specification provide methods and systems for clearing a detector of contaminants or any other undesirable substances that may affect operation of detector. The methods and systems enable a clear-down mode to clear the detector after an alarm is detected during sampling by the detector. The clear-down mode may be enabled immediately upon detecting a substance of interest. Further, the clear-down mode is effective to increase and direct all air flow through the detector in order to maximally purge contaminants from the detector.

A liquid chromatography having an on-line cleaning function, comprising a first flow channel (L3), a second flow channel (L21), an analysis flow channel (L22) and waste liquid flow channels, further comprising a cleaning flow channel (L25), a direction switch valve (V1) and a multi-flow channel switch valve (V2), etc. The liquid chromatography changes the flow path of the liquid by changing the communication relationship between the two-position switch valves, thus realizes the on-line cleaning function for a first chromatographic column (C1), a middle chromatographic column (C2), a filter or a protector (B2) respectively, and realize the simultaneous on-line cleaning function for the first chromatographic column (C1) and the middle chromatographic column (C2).

A liquid chromatography having an on-line cleaning function, comprising a first flow channel (L3), a second flow channel (L21), an analysis flow channel (L22) and waste liquid flow channels, further comprising a cleaning flow channel (L25), a direction switch valve (V1) and a multi-flow channel switch valve (V2), etc. The liquid chromatography changes the flow path of the liquid by changing the communication relationship between the two-position switch valves, thus realizes the on-line cleaning function for a first chromatographic column (C1), a middle chromatographic column (C2), a filter or a protector (B2) respectively, and realize the simultaneous on-line cleaning function for the first chromatographic column (C1) and the middle chromatographic column (C2).

A preparative purification apparatus capable of adjusting a mixing ratio of a mobile phase and an elution solvent contained in a solution to be collected. A liquid feeding unit which feeds an elution solvent to an inlet of a trap column; a flow path switching unit which selectively connects an outlet of the trap column to one of a waste liquid flow path or a recovery flow path; a liquid feed amount measurement unit; and a flow path control unit which performs a control such that the flow path switching unit is connected to the recovery flow path when the amount of the elution solvent fed to the trap column reaches a predetermined initial waste liquid amount, and thereafter, the flow path switching unit is connected to the waste liquid flow path at a timing of reaching a predetermined solution recovery amount.

A preparative purification apparatus capable of adjusting a mixing ratio of a mobile phase and an elution solvent contained in a solution to be collected. A liquid feeding unit which feeds an elution solvent to an inlet of a trap column; a flow path switching unit which selectively connects an outlet of the trap column to one of a waste liquid flow path or a recovery flow path; a liquid feed amount measurement unit; and a flow path control unit which performs a control such that the flow path switching unit is connected to the recovery flow path when the amount of the elution solvent fed to the trap column reaches a predetermined initial waste liquid amount, and thereafter, the flow path switching unit is connected to the waste liquid flow path at a timing of reaching a predetermined solution recovery amount.

Disclosed is an organic carbon detector that can be used with a liquid chromatography equipment such as a size exclusion chromatography. The organic carbon detector contains a carbon oxidization subsystem and a stripping and CO.sub.2 detection subsystem arranged and detachably connected with each other in said order. The carbon oxidization subsystem contains a microfluidic agent injection module (1), an inorganic carbon removal module (2), a microfluidic ultraviolet oxidation module (3) and a vacuum pumping system (4), configured to remove inorganic carbons and oxidize organic carbons. The stripping and CO.sub.2 detection subsystem contains a stripping module (7) and a CO.sub.2 detector (12), using a carrier gas to transfer the organic carbon converted gas to the CO.sub.2 detector (12). Also disclosed is a method of using the organic carbon detector in water quality monitoring.

Disclosed is an organic carbon detector that can be used with a liquid chromatography equipment such as a size exclusion chromatography. The organic carbon detector contains a carbon oxidization subsystem and a stripping and CO.sub.2 detection subsystem arranged and detachably connected with each other in said order. The carbon oxidization subsystem contains a microfluidic agent injection module (1), an inorganic carbon removal module (2), a microfluidic ultraviolet oxidation module (3) and a vacuum pumping system (4), configured to remove inorganic carbons and oxidize organic carbons. The stripping and CO.sub.2 detection subsystem contains a stripping module (7) and a CO.sub.2 detector (12), using a carrier gas to transfer the organic carbon converted gas to the CO.sub.2 detector (12). Also disclosed is a method of using the organic carbon detector in water quality monitoring.

Systems and methods for concentrating an analyte preparatory to analysis thereof include processing the effluent of an analyte concentrator to produce an eluent for eluting an analyte retained in the same or separate concentrator, and systems implementing the same. The analyte concentrator system connects the effluent outlet of an analyte concentrator column to an eluent generation module such that the substantially analyte-free effluent discharged from the analyte concentrator column passes fluidly into the eluent generation module. Eluent generated from the substantially analyte-free effluent in the eluent generation module is likewise substantially free of the analyte. The systems and methods can minimize and/or (substantially) eliminate background signal during analysis of the concentrated analyte.

Systems and methods for concentrating an analyte preparatory to analysis thereof include processing the effluent of an analyte concentrator to produce an eluent for eluting an analyte retained in the same or separate concentrator, and systems implementing the same. The analyte concentrator system connects the effluent outlet of an analyte concentrator column to an eluent generation module such that the substantially analyte-free effluent discharged from the analyte concentrator column passes fluidly into the eluent generation module. Eluent generated from the substantially analyte-free effluent in the eluent generation module is likewise substantially free of the analyte. The systems and methods can minimize and/or (substantially) eliminate background signal during analysis of the concentrated analyte.