106 results about "Capillary electrochromatography" patented technology

The present invention provides an on-chip packed reactor bed design that allows for an effective exchange of packing materials such as beads at a miniaturized level. In accordance with the present invention, there is provided a method of concentrating an analyte within a microfluidic analysis system, comprising the steps of: a) providing a main channel having a trapping zone suitable for trapping packing material; b) providing a slurry of a reagent treated packing material prepared in a solution having a predetermined composition of a solvent; c) inducing a flow of said packing material into said trapping zone through a flow channel connected to said trapping zone so as to load said trapping zone and form a packed bed of said packing material; d) and flowing a sample containing analytes through said packed bed, said reagent acting to concentrate at least some of said analytes within said trapping zone. The present invention extends the function of microfluidic analysis systems to new applications including on-chip solid phase extraction (SPE) and on-chip capillary electrochromatography (CEC). The design can be further extended to include integrated packed bed immuno- or enzyme reactors.

The present invention provides an on-chip packed reactor bed design that allows for an effective exchange of packing materials such as beads at a miniaturized level. The present invention extends the function of microfluidic analysis systems to new applications including on-chip solid phase extraction (SPE) and on-chip capillary electrochromatography (CEC). The design can be further extended to include integrated packed bed immuno- or enzyme reactors.

The present invention provides an on-chip packed reactor bed design that allows for an effective exchange of packing materials such as beads at a miniaturized level. The present invention extends the function of microfluidic analysis systems to new applications including on-chip solid phase extraction (SPE) and on-chip capillary electrochromatography (CEC). The design can be further extended to include integrated packed bed immuno- or enzyme reactors. The system comprises two weirs (6, 7) in a channel to trap packing material (12). The packing material might be introduced through a side channel to the chamber formed between the two weirs (6, 7). A plug is positioned in the side channel to close it.

An on-chip packed reactor bed design is disclosed that allows for an effective exchange of packing materials such as beads at a miniaturized level. Also disclosed is a method of treating a sample within a microfluidic analysis system, comprising: providing a main channel having a trapping zone; providing a slurry of a reagent treated packing material; inducing a flow of said packing material into said trapping zone through a flow channel connected to said trapping zone to load said trapping zone and form a packed bed of said packing material; and flowing a sample containing analytes through said packed bed, said reagent treating the sample. The present invention extends the function of microfluidic analysis systems to new applications including on-chip solid phase extraction (SPE) and on-chip capillary electrochromatography (CEC). The design can be further extended to include integrated packed bed immuno- or enzyme reactors.

The subject invention concerns zirconia-based hybrid organic-inorganic sol-gel coating for optional use as a stationary phase in capillary microextraction (CME), gas chromatographic (GC), high performance liquid chromatography (HPLC), capillary electrophoresis (CE), capillary electrochromatography (CEC) and related analytical techniques. Sol-gel chemistry is employed to chemically bind a hydroxy-terminated silicone polymer (polydimethyldiphenylsiloxane, PDMDPS) to a sol-gel zirconia network. In one embodiment, a fused silica capillary is filled with a properly designed sol solution to allow for the sol-gel reactions to take place within the capillary. In the course of this process, a layer of the evolving hybrid organic-inorganic sol-gel polymer becomes chemically bonded to the silanol groups on the inner capillary walls. The unbonded part of the sol solution is expelled from the capillary under helium pressure, leaving behind a chemically bonded sol-gel zirconia —PDMDPS coating on the inner walls of the capillary. Polycyclic aromatic hydrocarbons, ketones, and aldehydes are efficiently extracted and preconcentrated from dilute aqueous samples followed by GC separation of the extracted analytes.

The present invention provides for a column for use in capillary electrochromatography including a tube, wherein the tube includes an inner surface having a positively or negatively charged, chemically-bonded stationary coating thereon. The present invention further provides for a method of making a column for use in capillary electrochromatography, including a tube, wherein the tube includes an inner surface having a positively or negatively charged chemically-bonded stationary coating thereon, wherein the steps include filling the column with a sol-gel solution, maintaining the sol-gel solution within the column, and forcing the sol-gel solution out of the column with an inert gas. Further, the present invention provides for a method of analytical separation with a column including an inner layer having a positively charged chemically-bonded stationary coating thereon that reverses the direction of electroosmotic flow in the column compared with a column without the positive surface charge. Additionally, the present invention provides for a method of using a column including an inner layer of positively charged chemically-bonded stationary coating thereon by introducing a sample into the column operating under reversed electroosmotic flow due to positively charged chemically-bonded stationary coating.

The invention relates to a preparation method of a novel open tubular capillary electrochromatographic column for fixing hydroxyapatite as a stationary phase by adopting a bio-ore physical-chemical method. The hydroxyapatite is used as an inorganic material, and is short of active groups, thereby being difficultly fixed on the wall of a capillary tube for capillary electrochromatographic separation. The preparation method comprises the steps of: introducing a pre-oxidized dopamine solution into a preprocessed capillary tube, forming a polydopamine coating on the inner wall of the capillary tube; and introducing a 1.5-time simulated body fluid into the capillary tube modified by polydopamine, placing the capillary tube in a water bath kettle being 37 DEG C for incubation for two weeks, and growing a hydroxyapatite crystal with a nano structure on the inner wall of the capillary tube. The preparation method provided by the invention is simple in process, easy to operate and low in cost; and the whole preparation process is carried out in a water solution without polluting the environment. A hydroxyapatite open tubular column prepared by adopting the preparation method has a good separation effect on a neutral compound, an alkali compound and an acidic compound.

The present invention provides an on-chip packed reactor bed design that allows for an effective exchange of packing materials such as beads at a miniaturized level. The present invention extends the function of microfluidic analysis systems to new applications including on-chip solid phase extraction (SPE) and on-chip capillary electrochromatography (CEC). The design can be further extended to include integrated packed bed immuno- or enzyme reactors.

Spectroscopic chemical analysis methods and apparatus are disclosed which employ deep ultraviolet (e.g. in the 200 nm to 300 nm spectral range) electron beam pumped wide bandgap semiconductor lasers, incoherent wide bandgap semiconductor light emitting devices, and hollow cathode metal ion lasers to perform non-contact, non-invasive detection of unknown chemical analytes. These deep ultraviolet sources enable dramatic size, weight and power consumption reductions of chemical analysis instruments. Chemical analysis instruments employed in some embodiments include capillary and gel plane electrophoresis, capillary electrochromatography, high performance liquid chromatography, flow cytometry, flow cells for liquids and aerosols, and surface detection instruments. In some embodiments, Raman spectroscopic detection methods and apparatus use ultra-narrow-band angle tuning filters, acousto-optic tuning filters, and temperature tuned filters to enable ultra-miniature analyzers for chemical identification. In some embodiments Raman analysis is conducted along with photoluminescence spectroscopy (i.e. fluorescence and / or phosphorescence spectroscopy) to provide high levels of sensitivity and specificity in the same instrument.

The invention is a laser-inducing-fluorescence detector. It includes: a piece of inching equipment to plant and ajdust the position of sample holder; an aided light source to adjust the light path; an observation mirror for adjusting the light path; an exciting light source as its working light source made up of the laser, the reference photoelectric diode and light-reducing board and the dichroiscope; a group of optical lenses in imagine and focus the working light source, made up of the focus lens, the imagining lens, the light-filtering piece and the light diaphragm; and a photoelectric signal converter to receive and output the detecting signal. The invention is based on the common-focus mode to get the high-efficiency imagining system and it can be used in the separating-analysis technique such as Micro-HPLC, CE, CEC and so on.

The invention provides a preparation method for a novel ionic liquid silica gel capillary monolithic column stationary phase. The novel ionic liquid silica gel capillary monolithic column stationary phase is prepared by a sol-gel and gold nanoparticle surface functionalization technology. According to the characteristic that the gold nanoparticles have strong affinity on a ligand containing sulfydryl, amino and cyan and the excellent properties of the gold nanoparticles, the ionic liquid and the silica gel monolithic column, the prepared ionic liquid silica gel capillary monolithic column hasthe advantages of high selectivity, high column efficiency, simplicity in preparation, wide application rang and the like. An electropositive imidazole ring and an analyte have various kinds of interactions comprising a hydrophobic interaction, an ion exchange interaction, a pi-pi interaction, a dipolar interaction and a weak hydrophilic interaction and also have multiple action mechanisms such as a hydrogen bond action and the like. Therefore, the preparation method can be applied to separation analysis on hydrophobic neutral compounds, alkaline organic compounds, polar compounds and inorganic anions. The ionic liquid silica gel capillary monolithic column stationary phase can serve as a capillary electrochromatography or capillary liquid chromatography fixed phase and has good application potential in the field of separation science.

The invention relates to a preparation method for a grapheme open-tube electric chromatographic column, and relates to the preparation method for a novel capillary electric chromatographic column. In the method, a conductive polymer polyaniline assisted polydopamine bonded graphite oxide is used as a fixed phase. The conductive polymer polyaniline is bonded to the inner wall of a capillary to serve as an underlying material, so that the specific surface area of the capillary is increased, the modification time and the modification frequency of dopamine are remarkably reduced, and the modification degree of the polydopamine is improved; and therefore, the reaction of the graphite oxide is facilitated. The preparation method is easy to operate and low in cost; the overall preparation process is performed in aqueous solution, and an organic solvent or a toxic reagent is not used; the environment is not polluted; each prepared coating has the high stability; the service life of the capillary column is long; according to the grapheme open-tube electric chromatographic column prepared by using the preparation method, the chromatographic performance of the grapheme open-tube column is remarkably improved, and the effect on separating the homologs of benzene is better compared with that of a polydopamine bonded graphite oxide open-tube.

The present invention provides for a column for use in capillary electrochromatography including a tube, wherein the tube includes an inner surface having a positively or negatively charged, chemically-bonded stationary coating thereon. The present invention further provides for a method of making a column for use in capillary electrochromatography, including a tube, wherein the tube includes an inner surface having a positively or negatively charged chemically-bonded stationary coating thereon, wherein the steps include filling the column with a sol-gel solution, maintaining the sol-gel solution within the column, and forcing the sol-gel solution out of the column with an inert gas. Further, the present invention provides for a method of analytical separation with a column including an inner layer having a positively charged chemically-bonded stationary coating thereon that reverses the direction of electroosmotic flow in the column compared with a column without the positive surface charge. Additionally, the present invention provides for a method of using a column including an inner layer of positively charged chemically-bonded stationary coating thereon by introducing a sample into the column operating under reversed electroosmotic flow due to positively charged chemically-bonded stationary coating.

The invention relates to a preparation method of a capillary electro-chromatography column taking beta-cyclodextrin as a bonded stationary phase and an application in a chiral drug separation, and can effectively solve the problems of the capillary electro-chromatography column preparation and the chiral drug separation. The solved technical proposal comprises the following steps: (1) preparing six-bit mono substituted P-toluenesulfonyl-beta-cyclodextrin, (2) preparing six-bit mono substituted ammoniated-beta-cyclodextrin, (3) preparing silylated silica gel, (4) preparing a beta-cyclodextrin bonded silica gel chiral stationary phase, and (5) preparing a capillary packing column. The preparation method is low in cost, low in toxicity and low in environment pollution, and is an innovation of the preparation method of the capillary electro-chromatography column taking the beta-cyclodextrin as the bonded stationary phase and the application in the chiral drug separation.

The invention relates to a chromatographic analysis technology, in particular to the application of bi-phenylene hybrid silica-gel monolithic column of bridge-bond organic-inorganic hybridization periodically meso-pore separation material in a chromatogram. The specified preparation method of bi-phenylene hybrid silica-gel material adopts a sol-gel method of acid-base catalysis. Under the condition of acid catalysis, hydrolysis reaction is carried out to a monomer, and an alkaline catalyst is added to carry out polycondensation reaction. The reaction rates of the hydrolysis reaction and the polycondensation reaction of the monomer are controlled by controlling and changing the pH value of a reaction system in the reaction process and the hydrolysis reaction and the polycondensation reaction of the monomer are effectively completely separated by the two-step catalysis method so as to obtain monolithic or particle material with uniform frame structure, suitable aperture and periodic meso-pores. Therefore, the chromatographic analysis technology meets the demands of separation, improves processing technology of the internal wall of quartz capillary, obtains stable monolithic separation material, is capable of separating acid, neutral and alkai compounds under the model of capillary electrochromatography, and shows that the material has excellent separation efficiency and separative selectivity.

The invention relates to a multidimensional chromatography combination separation device, which comprises a pressurized capillary electrochromatography unit. The pressurized capillary electrochromatography unit comprises a mobile phase driving device, an injection valve, a capillary chromatographic column and a buffer solution bottle which are connected mutually and sequentially, a high-voltage power supply connected in parallel with the capillary chromatographic column, and a detector connected on the capillary chromatographic column. The separation device also comprises a capillary ion-exchange chromatography unit. The capillary ion-exchange chromatography unit comprises a mobile phase driving device, an injection valve and a capillary ion-exchange chromatography column which are connected mutually and sequentially. The capillary ion-exchange chromatography column is connected with an injection port of the injection valve of the pressurized capillary electrochromatography unit. The multidimensional chromatography combination separation device has the advantages of high separation efficiency, large peak capacity, small sample dosage, low raw material cost and low pollution, has more excellent peak capacity and separation capacity than the conventional one-dimensional chromatography, pressurized capillary electrochromatography, two-dimensional liquid chromatography and the like, and is more suitable for analysis of the complex sample.

The invention belongs to the technical field of chromatographic columns, particularly relates to a mesoporous material coating based open-tubular capillary chromatographic column as well as a preparation method and an application thereof. The preparation method provided by the invention comprises the following steps: dissolving a surfactant into a certain amount of ethanol; then, adding a certainamount of silicon sources and functionalized silicon sources into the ethanol; and finally, adding a little bit of water and hydrochloric acid into the ethanol, then heating and stirring the obtainedmixture for a considerable period at an appropriate temperature so as to obtain a sol. Through changing the type and application amount of the surfactant, the mesoporous material structure is changedfrom a one-dimensional structure to a three-dimensional structure, and the hole diameter (2nm-10nm) is adjustable. After the sol is coated on the inner wall of an open tubular column (quartz capillary with an inner diameter of 10-50 microns), an acid solution of alcohols is fed into the open tubular column so as to remove the surfactant. The obtained open tubular column is used for CEC (capillaryelectro-chromatography) and CLC (capillary liquid chromatography) separable aromatics and chiral compounds, and the like.

The invention discloses a cation type chitosan bonded and modified capillary electrochromatography open tubular column and a manufacturing method thereof. The open tubular column is manufactured by adopting the modifying technologies of silanizing the inner surface of a capillary, modifying aldehyde groups of the capillary wall, polycondensating and bonding chitosan amine aldehyde, crosslinking chitosan molecules, and the like. In the invention, cation type chitosan is bonded in the manufactured capillary open tubular column, and the used cation type chitosan is carboxymethyl chitosan. The cation type chitosan bonded and modified capillary electrochromatography open tubular column has the advantages of firm functional coating chemical bonding, stable quality, double action modes of cathode / anode electroosmotic flows, good separation effect on alkaline protein molecules and active alkaloid and good repeatability, and is suitable for separating and analyzing capillary electrochromatography of positive charge type substances.

An apparatus for analyzing a mixture of sample substances comprises a fluid-guiding structure wherein the sample substances are moving essentially in one dimension along the structure and are subject to at least two separation mechanisms, such as capillary electrochromatography (CEC) and capillary zone electrophoresis using high voltage. The signals from a detection means are supplied to a signal processing means, which derives a parameter therefrom which in turn is used to derive improved measuring results for each of the separation results associated with the various separation mechanisms, respectively. The apparatus can be used for protein analysis, for example in combination with a mass spectrometer.

The invention discloses a preparation method of graphene-modified capillary-column chromatography. Oxidized graphene groups are deposited on the inner wall of a capillary through cationic polyelectrolyte by using a layer by layer self-assembling method, so that the defects of complex chemical bonding method and short service life of a dynamically-coated column and the like are overcome. Raw materials are easily obtained; the method is simple, convenient and stable; and the prepared capillary-column chromatography is longer in service life.

The invention discloses a preparation method of a capillary electrochromatography column filled with fiber, comprising the following steps: one end of the fiber is inserted into the capillary, fluid is conveyed into the connection end of the fiber and the capillary for lubrication, the other end of the capillary is connected with a vacuum pump, vacuum is imposed and the fiber is pumped into the capillary. The adopted lubricate fluid is polar solvents, such as methanol, acetone and water and the like; the filled fiber is silica fiber or glass fiber or fiber with bonding functional groups on the surface, the diameter of the fiber is 5 to 450 Mum and the length thereof is 1cm to 50 cm; the capillary forming the capillary electrochromatography column is a fused silica capillary or polyether ketone capillary or metal capillary or capillary with bonding functional groups on the internal surface and the inner diameter of the capillary is 10 to 500 mum. The method of the invention has simple operation, and the needed material is easy to obtain and can fill the fiber into the capillary electrochromatography column conveniently.

The invention relates to a method for detecting sulfonamide residues in eel by pressurized capillary electrochromatography, which is characterized in that the method comprises the following steps: extracting a sample by ethyl acetate, purifying the sample by a HLB solid-phase extraction column, and filtering the sample by a 0.22-micron filter membrane, performing analysis by pressurized capillary electrochromatography, performing detection at 270 nm with an ultraviolet detector by using a capillary electrochromatographic column with reversed-phase bonds and C18 as fillers as a detection column, wherein the mobile phase is acetonitrile and sodium dihydrogen phosphate (5 mmol / L, pH 6.0) with a ratio of 30:70 (V / V). The invention performs pretreatment of the sample by using a classic sample treatment method of liquid-liquid extraction combined with solid-phase extraction, and effectively reduces the content of impurities in fish flesh tissue and matrix interference; the capillary electrochromatography is adopted for analysis and detection, which has less organic reagent consumption; with the application of an external voltage, the retention time of 5 sulfonamides is reduced; the sensitivity is improved; 5 sulfonamides are separated and detected simultaneously; the method of the invention not only meets routine detection of eel sulfonamide residual quantities, but also is applicable to the detection of sulfonamides in other aquatic product samples.

The invention discloses a capillary electrochromatography enzyme microreactor based on functionalized graphene and a preparation method thereof. The preparation method comprises the following steps: (1) pretreating a capillary tube, namely pretreating a capillary tube with alkalis and acids; (2) preparing a graphene substrate based capillary electrochromatography, namely fixing graphene oxide or carboxyl graphene on the inner wall of the capillary tube so as to obtain the graphene substrate based capillary electrochromatography, or preferably fixing the graphene oxide or carboxyl graphene on the inner wall of a whole capillary tube; and (3) preparing an enzyme microreactor, namely introducing a protease solution into one end of the graphene substrate based capillary electrochromatography, performing incubation, and washing with a buffer solution, thereby obtaining the capillary electrochromatography enzyme microreactor based on functionalized graphene. The capillary electrochromatography enzyme microreactor based on functionalized graphene, which is disclosed by the invention, integrates biochemical reactions and separation, and furthermore is high in enzyme immobilization activity, high in separation efficiency for substrates, enzymolysis products and the like, and good in effect.

The invention provides a graphene oxide bonding capillary electrochromatography monolithic column. A preparing method of the graphene oxide bonding capillary electrochromatography monolithic column comprises the steps that GO and DMF are mixed and subjected to ultrasonic dispersion, then, pAS and DCC are added, reaction is conducted at the temperature of 40-80 DEG C under the argon protection condition in dark in a stirring mode for 12-48 h, reaction liquid is filtered, and pAS-GO is obtained; the pAS-GO is mixed with cyclohexanol and subjected to ultrasonic dispersion, then, styrene, DVB, methylbenzene, a radical initiator and AMPS are added, ultrasonic dispersion continues to be conducted, nitrogen is injected into the mixture, and reaction mixed liquid is obtained; the obtained reaction mixed liquid is introduced into a position of a preset stationary phase in a preprocessed capillary tube, then, the two ends of the capillary tube are sealed through silica gel, the capillary tube is put at the temperature of 40-100 DEG C to be subjected to curing reaction for 6-24 h, post-processing is conducted on the capillary tube, and the graphene oxide bonding capillary electrochromatography monolithic column is prepared. The reaction process is simple, the number of steps is small, reaction conditions are controllable, and the preparation effect is more ideal.

The invention relates to a method for detecting tripolycyanamide in an aquatic product via pressurized capillary electrochromatography, which comprises the steps of: 1) sample preparation; 2) sample pretreatment: centrifugal extraction of a sample by mixed solution of trichloroacetic acid with the mass concentration of 0.8-1.2 percent and acetonitrile at the volume ratio of (1.5-2.5):1, purification by an MCX (methoxycinnamate) solid-phase extraction column, and filtration by a filter film of 0.20-0.24mum for determination via the pressurized capillary electrochromatography; 3) preparation of standard tripolycyanamide solution; 4) analysis via the pressurized capillary electrochromatography; and 5) detection and analysis of the sample, quantitative analysis according to the retention time, and then quantitative analysis in an external marking method according to the peak area. The analytical method is efficient, accurate and highly sensitive, and the demands of drug detection of the tripolycyanamide in the daily aquatic product can be satisfied.

The invention discloses a preparation method of a carbon-titanium dioxide chromatography stationary phase with a shell-core structure and an application, relating to the preparation method of the stationary phase and the application. The preparation method can solve the problems that as the density of metal oxide microspheres is higher, the chromatography stationary phase taking a metal oxide as a matrix is very difficult to fill out a chromatographic column with high column efficiency through the homogenization method. The method comprises the following steps: adding prepared carbon spheres into TiO2 sol, carrying out ultrasonic treatment, standing, carrying out centrifugation, and then obtaining the carbon-titanium dioxide chromatography stationary phase with the shell-core structure which is used in capillary electrochromatography and high-performance liquid chromatography under the condition of N2 protection. The carbon spheres are taken as the matrix, and the carbon spheres have uniform particle size distribution, good appearance, large specific surface area and high strength. TiO2 high-performance particles are enriched on the surface of the obtained carbon-titanium dioxide chromatography stationary phase with the shell-core structure, and the carbon-titanium dioxide chromatography stationary phase has high surface activity and is resistant to high temperature and extreme pH; and the carbon-titanium dioxide chromatography stationary phase is used in the high-temperature high-performance liquid chromatography separation technology, and has good separation effect, high efficiency and strong repeatability.

The invention relates to a device and a method for preparing a chromatographic column made of a magnetic filling material. In the preparation method, magnetic materials or magnetic materials with a shell-core structure are used as a substrate of a chromatographic fixed phase to prepare the chromatographic fixed phase by surface modification, and the chromatographic fixed phase can be used for separation of a capillary electrochromatography, a liquid phase chromatography or a gas phase chromatography; for the filling materials with a bigger grain size, the pneumatic and slurry pole assembling methods and other pole assembling methods are adopted to complete the pole assembly, and an electromagnetic gun device designed in the invention is further used for tamping; and for the fixed phase with the smaller grain size or nanometer grain size, the electric filling method is used for filling, and the electromagnetic gun device is further used for tamping. The invention has the advantages that: the filling device is convenient in use, simple in structure and easy to configure and operate; and the chromatographic column fixed phase of the magnetic filling materials prepared by the method is uniform and dense and has a high chromatographic column efficiency.

The present invention provides a pressurized capillary electrochromatography electrochemical detection device comprising a liquid storage tank of mobile phase, a high pressure pump used for carrying the mobile phase and providing liquid to a separation capillary electroosmotic chromatography connected to a detection cell through a microflow controller in which a sample can be input, a high voltage power supply which both ends are applied respectively to a liquid intake terminal of the capillary electrochromatography and a detection cell connected to an electrochemical detector which output terminal signals are connected to a computer through a signal gathering analysis meter. By combining the capillary electrochromatography separation technology and the electrochemical detection technology, the present invention is capable of separating, quickly and efficiently, and detecting, with a high sensitivity, species having electrochemical activity.

The invention relates to the field of analytical instrument research, and particularly relates to a detection method of a high-sensitivity laser-induced fluorescence detection device suitable for detection on a capillary column. The high-sensitivity laser-induced fluorescence detection device is characterized in that laser light is emitted from a laser, is filtered by a laser light filter, reflected by a dichroscope placed at a 45-degree angle relative to a horizontal plane and focused by an objective lens and finally enters a channel of a circular capillary tube from a position horizontally deviating from the center of the capillary tube by a certain distance so as to excite a component to be tested in the channel to generate fluorescence, and the fluorescence generated by excitation is collected by the objective lens, passes through the dichroscope, a focusing lens, a spatial filtering micropore and a fluorescence light filter respectively and finally enters a photoelectric detection device. The detection method not only is suitable for micro-column separation systems of capillary electrophoresis, capillary chromatography, capillary electrochromatography and the like, but also can be applied to analytic systems for flow injection analysis, sequence injection analysis, microfluidic liquid drop analysis, flow cytometry and the like based on circular capillary flow cells.