The present disclosure relates to a method of synthesizing cyclosporine derivatives. The method includes: providing a precursor fluid of the cyclosporine derivative, an alkaline fluid and a ClCH.sub.2OCOCl solution; premixing the precursor fluid and the alkaline fluid to obtain a premixed solution; feeding the premixed solution into a first reaction chamber, reacting to prepare a first reaction liquid; feeding the first reaction liquid into a second reaction chamber, reacting the first reaction liquid with a CO.sub.2 fluid to prepare a second reaction liquid; and reacting the second reaction liquid with the ClCH.sub.2OCOCl solution.

The present disclosure relates to a method of synthesizing cyclosporine derivatives. The method includes: providing a precursor fluid of the cyclosporine derivative, an alkaline fluid and a ClCH.sub.2OCOCl solution; premixing the precursor fluid and the alkaline fluid to obtain a premixed solution; feeding the premixed solution into a first reaction chamber, reacting to prepare a first reaction liquid; feeding the first reaction liquid into a second reaction chamber, reacting the first reaction liquid with a CO.sub.2 fluid to prepare a second reaction liquid; and reacting the second reaction liquid with the ClCH.sub.2OCOCl solution.

A concentrator includes a casing, a separation membrane that sections an inner space of the casing to form a flow path in the casing, a first supplier that supplies a first liquid from a first position of the casing to the flow path such that the first liquid flows along the separation membrane in a first direction, a second supplier that supplies a second liquid from a second position of the casing to the flow path such that the second liquid flows along the separation membrane in a second direction opposite to the first direction, and a third supplier that supplies a third liquid including a target component having a size that does not allow permeation of the target component through the separation membrane from a third position of the casing to the flow path.

A method of analyzing a polymer resin comprising: providing a polymer resin sample having two or more polymer components; subjecting the sample to aTREF analysis to yield aTREF elution trace by contacting the sample with aTREF solvent to form sample solution; introducing sample solution into aTREF column and allowing elution of polymer components at different elution rates along the column; eluting from the aTREF column an aTREF eluent comprising the polymer components eluting at different rates; and subjecting the aTREF eluent to IR detection to yield the aTREF elution trace; identifying the components of the sample to yield identified components by comparing the elution trace with an identification library that comprises a plurality of known polymer aTREF elution traces correlated with known polymer components characterized by identifying parameters (density, SCB, crystallization temperature, MI, HLMI, MWD); and quantifying each of the identified components to yield quantified polymer components via chemometric analysis.

A method of analyzing a polymer resin comprising: providing a polymer resin sample having two or more polymer components; subjecting the sample to aTREF analysis to yield aTREF elution trace by contacting the sample with aTREF solvent to form sample solution; introducing sample solution into aTREF column and allowing elution of polymer components at different elution rates along the column; eluting from the aTREF column an aTREF eluent comprising the polymer components eluting at different rates; and subjecting the aTREF eluent to IR detection to yield the aTREF elution trace; identifying the components of the sample to yield identified components by comparing the elution trace with an identification library that comprises a plurality of known polymer aTREF elution traces correlated with known polymer components characterized by identifying parameters (density, SCB, crystallization temperature, MI, HLMI, MWD); and quantifying each of the identified components to yield quantified polymer components via chemometric analysis.

A liquid chromatograph includes: a concentration column for capturing a target component; an analysis column for separating the target component from other components; first passage-switching units for switching between the state of forming a passage through which a sample-introduction mobile phase containing the liquid sample is fed to the concentration column, and the state of forming a passage through which an eluant for eluting the target component captured in the concentration column is fed to the concentration column; a storage unit for storing the eluant; and a second passage-switching unit for switching between the state of forming a passage through which an analysis mobile phase is fed to the analysis column and a passage through which the eluant from the concentration column is fed to the storage unit, and the state of forming a passage through which analysis mobile phase is fed to the analysis column via the storage unit.

Disclosed herein is a method for analyzing the concentration of a fluorescent compound in the plasma of a patient. The method includes collecting a sample of plasma from a patient, diluting the sample with a solvent and analyzing the diluted sample by HPLC. The sample does not need to be dried down during sample preparation nor is an internal standard required.

Disclosed herein is a method for analyzing the concentration of a fluorescent compound in the plasma of a patient. The method includes collecting a sample of plasma from a patient, diluting the sample with a solvent and analyzing the diluted sample by HPLC. The sample does not need to be dried down during sample preparation nor is an internal standard required.

Ion chromatography may be used for measuring the concentration of metal ions in various streams of a vinyl acetate production process. For example, a method may comprise: reacting ethylene, oxygen, and acetic acid in the presence of a catalyst and optionally a catalyst promotor like sodium acetate and/or potassium acetate to yield a crude vinyl acetate stream; measuring a concentration of a metal ion of the crude vinyl acetate stream and/or a stream downstream thereof with an ion chromatograph, wherein the metal ion is selected from the group consisting of Group I metal ions, Group II metal ions, transition metal ions, and any combination thereof.

Ion chromatography may be used for measuring the concentration of metal ions in various streams of a vinyl acetate production process. For example, a method may comprise: reacting ethylene, oxygen, and acetic acid in the presence of a catalyst and optionally a catalyst promotor like sodium acetate and/or potassium acetate to yield a crude vinyl acetate stream; measuring a concentration of a metal ion of the crude vinyl acetate stream and/or a stream downstream thereof with an ion chromatograph, wherein the metal ion is selected from the group consisting of Group I metal ions, Group II metal ions, transition metal ions, and any combination thereof.