A liquid junction assembly for providing a flow connection between two tubular conduits. The assembly includes respective bodies configured to define elongated passages of respective first and second cross sections to receive and locate the respective tubular conduits, a plate with at least one hole therethrough of a third cross section smaller than the first and second cross sections, and a seat for the plate, defined in a face of one or both of the bodies. The bodies and the plate are assembled with the plate in the seat and the elongated passages and the hole aligned along a common axis.

The invention provides a process of controlling the impurities of clindamycin hydrochloride, comprising a step of purifying said clindamycin hydrochloride by two-phase high performance liquid chromatography, wherein the chromatographic conditions are as follows: the detection wavelength is 200-220 nm; the column temperature is 20-40° C.; the flow rate is 0.8-1 ml/min; Mobile phase A: 0.025 mol/L potassium dihydrogen phosphate solution; Mobile phase B: Acetonitrile; and gradient elution is performed. The method of controlling impurities of the invention can solve the problem of the interference by excipients and the problem of the separation of many impurities at the same time. It also provides an effective method for setting quality standard of impurities in such a formulation.

The present invention discloses a circulating multidimensional liquid chromatography and application thereof. The liquid chromatography comprises an infusion device, a sampling device, a collecting-resampling device, a chromatographic column switching device and a detecting device which are connected sequentially, wherein the collecting-resampling device comprises a collecting valve and a sample ring, and the collecting valve is connected with the sample ring; the sampling device is successively connected with the collecting valve and the chromatographic column switching device; the detecting device is also connected with the collecting valve; and the collecting valve is a three-slot three-position multi-way valve. The present invention adopts the three-slot three-position multi-way valve as the collecting valve, and the creative rotor flow path design can simultaneously satisfy the requirements of collection and resampling of the circulating multidimensional liquid chromatography, and greatly simplifies the hardware configuration.

A crescent PLOT column is disclosed, including a capillary column having an inlet, an outlet, a bore, and an inner surface surrounding the bore and extending between the inlet and the outlet. A layer of particles is localized on a radial portion of the inner surface. The layer of the particles includes a radial thickness decreasing from a center of the radial portion to a periphery of the radial portion, forming a crescent shape in a radial frame of reference. A method for preparing the crescent PLOT column is disclosed, including loading the capillary column with a fluid including a carrier and particles such that the fluid is contained within the capillary column. The capillary column and the fluid contained within the capillary column are subjected to a centrifugal force. The carrier is removed, and a layer of the particles is localized on the radial portion of the inner surface.

A gas chromatography guard column assembly is disclosed including a guard column having an inlet and an outlet. The guard column is disposed in a coil having a column coil aspect ratio of less than 15. A gas chromatography system is disclosed including an oven cavity, a heater assembly, an inlet, a guard column, an analytical column, and a detector. The guard column is in fluid communication with the inlet and is disposed in a guard column coil. The analytical column is in fluid communication with the guard column and is disposed in an analytical column coil. The detector is in fluid communication with the analytical column. The analytical column coil has an analytical column coil central axis aligned with a central axis of the heater assembly, and the guard column coil has a guard column coil central axis remote from the central axis of the heater assembly.

A device for separating one or more molecules of interest in a liquid specimen including a monolithic body defining a fractionation column. The column includes an inlet opening at a proximal end of the fractionation column; an outlet opening at a distal, opposite end of the fractionation column; a solid phase chamber positioned between the inlet opening and the outlet opening; a specimen introduction area adjacent a proximal end of the solid phase chamber; an analyte exit area adjacent a distal end of the solid phase chamber; an inlet chamber adjacent the inlet opening that tapers into the specimen introduction area; and an outlet chamber that extends from the analyte exit area to the outlet opening. A metered amount of solid phase packed within the solid phase chamber between a first porous frit and a second porous frit of the solid phase chamber.

A GC interface assembly for a heated transfer line of a gas chromatography interface probe, the heated transfer line comprising an inner tube and an outer tube, the GC interface assembly comprising: a GC fitting securable to said inner tube, the GC fitting comprising a first section comprising a substantially cylindrical projection for fluid connection to a GC source in use, and a second section having a larger radius than the first section in at least one direction, the second section being provided with at least one flat; and a GC end cap securable to an outer tube, the GC end cap comprising an aperture which slidably receives the second section of the GC fitting in use such that the GC fitting is substantially constrained to liner movement with respect to the GC end cap.

A GC fitting for an inner tube of a heated transfer line of a gas chromatography interface probe, the fitting comprising a first section comprising a substantially cylindrical projection for fluid connection to a GC source in use, and a second section having a larger radius than the first section in at least one direction, the second section being provided with at least one flat.

Provided is a supercritical fluid apparatus including: an analysis flow path through which a mobile phase flows; a back-pressure control valve provided at a downstream end of the analysis flow path to adjust pressure in the analysis flow path to a predetermined pressure; a small-diameter pipe connected to the outlet of the back-pressure control valve, having an inner diameter allowing internal pressure to be maintained at a pressure higher than the atmospheric pressure; a large-diameter pipe connected to a downstream end of the small-diameter pipe, having a larger inner diameter than the small-diameter pipe; and a large-diameter pipe heating part for heating the large-diameter pipe.

A new electrospray emitter capable of cone-jet mode spray for liquid flow-rates from sub-microliter/minute to 10's of microliters/minute is provided. The high efficiency of ionization and vaporization enabled by the disclosed spray emitter provides improved sensitivity for mass spectrometer detection. The disclosed spray emitter sprays consistently and robustly a liquid buffer having a large range of compositions of aqueous and organic solvents, and is not sensitive to the polarity of the electric field used to induce spray. The fluidic channel leading to the spray emitter opening does not have an internal taper rendering the spray emitter clog-resistant.