Rheodyne system

As previously described, Eq. 6 contains two constants characteristic of the system and the sample, feo and S, which can be determined by two chromatographic mns differing only in tc. These two values allow to calculate log fe using Eq. 4. However, because there is no empirical solution, values of log few and S have to be computed by iteration. Such procedures are included in several commercially available LC software packages, such as Drylab (Rheodyne, CA, USA), Chromsword (Merck, Darmstadt, Germany), ACD/LC simulator (Advanced Chemical Development, Toronto, Canada) or Osiris (Datalys, Grenoble, Erance). This approach was comprehensively described and successfully applied for accurate log P determination of several solutes with diverse chemical structures [9, 12, 43, 50]. 

The equipment consisted of two Waters (Waters Corp. Milford, MA) M-45 pumps, a Waters 481 UV detector, a six-port Valeo sampling valve (A2L6P) with 0.08" holes in the valve body and rotor, a Rheodyne Model 7413 injection valve with a 1-pl loop, a valve interface box, and a Digital Equipment LSI-11/23-based microcomputer system. The microcomputer was used to control all valves, collect raw data from the UV detector, integrate the chromatogram, and store and plot results. 

The equipment used in this application included two Waters M-45 pumps, a Waters 481 UV detector with microbore cell, an air-actuated Rheodyne 7413 injection valve with a 1-pl injection loop, an air-actuated Valeo four-port sampling valve (A2CI4UW2) with no groove in the injection entry ports, an air-actuated Valeo three-port switching valve (AC3W), and a Digital Equipment LSI-11/23 microcomputer. The LC system was located in a purged cabinet suitable for use in Class I, division 2 areas. The cabinet was in a heated room about 40 feet from the reactor column. The two Valeo valves were mounted next to the reactor column, while the microcomputer was located in the control room. 

Electrospray (ES) mass spectrometry was carried out with a Fisons platform quadrupole mass specfrometer coupled fo a VG Masslynx data system. The samples were introduced into the source by direct injection via a valve loop system. Loop injection was accomplished with a Rheodyne 7125 injector valve, placing a 10-pl loop in the acetoni-trile/water stream. 

Apparatus Pumping systems used in these studies for high-performance columns were a Varian 8500 syringe pump and a Varian 5000 isocratic pump. An Altex IlOA was employed for the con-trolled-pore glass (CPG) columns. Waters Associates model 401 refractometers were used on all instruments. Stagnant mobile phase was kept in the reference side of the refractometer. Samples were injected with a Rheodyne 70-10 injection valve using a 20yl loop (lOOyl for CPG columns). 

SEC System, Data Processing, and Chromatography Procedures. The SEC/LALLS system contained a Model IlOA pump (Altex), Model 7125 injector (Rheodyne), KMX-6 Low-Angle Laser Light Scattering Photometer (LDC/Milton Roy), and a Model 98.00... 

The assay was performed with a HPLC-system consisting of a Spectra-Physics (Spectra Physics, San Jose, CA 95134, USA) model SP8700 solvent delivery system used at a flow rate of l.Oml.min", a Kratos (Kratos Analytical Instruments, Ramsey, NJ 07446, USA) model 757 UV-detector, wavelength 260 nm, range 0.005 aufs, rise-time 1 second. Injections of extracts into a Zymark (Zymark Corporation Inc., Hopkinton, MA 01748, USA) Z 310 HPLC-injection station, equipped with an electrically controlled Rheodyne valve and a 20 pi sample loop, were performed by a Zymate II robot system. The Zymark Z 310 Analytical Instrument Interface was used to control the HPLC-injection station. 

This simple HPLC system needs only a pump (e.g., Model 515, Wates), an injector (e.g., Model 7725i, Rheodyne), a precolumn (e.g., Spherisorb C8 40x4.6 mm... 

Chromatography conditions. HPLC was performed using a Milton Roy HPLC system (Riviera, FL, USA), consisting of a Constametric 3000 Series isocratic pump, a Rheodyne injector (Rheodyne L.P., Cotati, CA, USA), and a... 

The continuous-stream flow-injection system (Figure 2) consisted of a gravity-feed electrolyte reservoir, a sample injection valve (Rheodyne, Model 50) fitted with a 30 /xL-sample loop, and a flow-through electrochemical detector cell. The channel diameter of the Teflon tubing for the stream was 0.8 mm. The tubing length from injector to detector was 10 cm. 

FIGURE 3-4. Effect of bandspreading upon performance. Same as Figure 3-3, except with a column and system having much lower dispersion 2 mm ID x 100 mm column 200 /xL/min flow rate and a 2 /xL sample. (Reproduced with permission of Rheodyne.)... 

Before each experiment, the jacketed stainless steel (Top Industrie, Dommarie-Les-Lys, France) reactor is opened. A precise amount of substrates and water (Table 2) are introduced within the reactor. After sealing, pressurization is achieved by pumping liquid carbon dioxide (Minipump, Dosapro-Milton Roy, Pont-St-Pierre, France) to the desired final pressure (12.5 MPa). The reactor is then isolated from the C02 circuit. Then 20 mg of lipozyme TM of various diameter distributions (Table 1) is introduced in the reactor with an original system, giving the zero time of the reaction and the stirring is switched on. A 6-way UPLC valve (Rheodyne 7125) permits to withdrawn 50 pi samples for analysis without depressurization. 

A Rheodyne six-port valve is added in order to purge the system without crossing the extraction cell. 

Molecular weights were obtained by GPC in dichloromethane (1 mL/min) using a Waters pump model 6000, an injector (Rheodyne) and a refractive index detector (RID-6A Shimadzu), equipped with a PL gel 5)iim mixed-C linear column. The system was calibrated using polystyrene standards with low polydispersity. 

The sample is introduced into the system via an injection valve, but this - a much simpler and less expensive valve than that found in an hplc 75tem. We use a Rheodyne type 50 Teflon rotary valve, which will take a 3w rate of lOOml/min (Fig. 11.24). The pump and the column are -lanected to the red and white connectors respectively, whilst a sample load 33p (see below) is fitted to the black and yellow connectors. A Luer fitting. 3 attached to the blue connector, which is where the sample is introduced, ->ing a syringe. The green connector is a vent and should be positioned so jiat effluent from it can be collected in a beaker or flask. 

HPLC was performed using Waters 600S solvent delivery system (Waters, Milford, MA, U.S.A.). 2487 UV dual channel detector of Waters was used and injector (20 fit sample loop) from Rheodyne. The data acquisition system was Millenium (Waters). Water filtered 1 Milipore ultra-pure water system (Milipore, Bedford, MA, USA). The wavelength was fixed at 254 nm and the experiment was performed at room temperature. The size of the analytical colunm packed by C g was lS0X4.6mm (Spm) (Alltech, USA). The mobile phase of 0.75% TFA in water and acetonitrile were used in this experiment. The flow rates of the mobile phase were fixed at I ml/min. The constant volume of 0(d, was injected. This experiment was implemented at room temperature. The gradient mode was employed to isolate peptides. The complete gradient condition was listed in Table I. 

The analytical HPLC column used for analysis was packed in 300 x 3.9 nin stainless column with Lichrospher lOORP-18 packing(lS urn, Merck Co.). The HPLC used for analysis consists of a M930 Solvent Delivery Pump, a 486 detector (M 7200 Absorbance Detector) from Young-ln Scientific Co, and a Rheodyne injection valve (20 pi sample loop). Autochrowin (ver. 1.42, Young-ln Scientific Co.) connected to PC was used as data acquisition system. 

With the exception of on-line trace enrichment and/or derivatisation systems, the form of injection is almost exclusively by use of a sample loop with rotary valve (Rheodyne or similar). Normally the size of sample loop is used to decide sample size rather than injection volume. As in other types of laboratory, septum type injection systems in environmental laboratories have long been superseded. 

Analytical Detector, and a Rheodyne injector (SO-pL sample loop). The data acquisition system was a Chromate (Ver. 3.0 Interface Engineering, South Korea) installed in a PC. The flow rate of mobile phase was fixed at 4, 2, and 1 mL/min with CIM QA, QlOO, and HiTrap Q, respectively. The wavelength was fixed at 260 and 280 nm and the injection volume was fixed at 20 pL. The experiment was performed at room temperature. 

The HPLC system consisted of a Varian Model 5560 liquid chromatograph equipped with a constant-flow pump, a variable wavelength detector (Varian, Instrument Group/Walnut Creek, CA), a Rheodyne injector valve and an Alltech Spherisorb ODS column, 4.6 mm id x 25 cm (Alltech/Applied Science, IL). The mass spectrometer was a Finnigan Model 4600 quadrupole instrument with... 

Many different types are available from numerous manufacturers. Different brands must not be mixed They often differ in the angle of the ferrule and in their stop depth, from 0.1700 in = 4.32 mm (Rheodyne) to 0.0800 in = 2.03 mm (Valeo). Usually the thread is English not metric but the length of the thread is also not identical with all brands. If the stop depth is less than it should be there is an extra-column volume in the system if it is too long the capillary will be damaged or the column frit will be pushed into the chromatographic bed. 

The HPLC-PO-CL system (Fig. 2) consisted of two LC 9A liquid chromatographic pumps (Shimadzu, Kyoto, Japan), a Rheodyne 7125 injector (Cotati, CA, USA) with a 20- tL sample loop, an ultraviolet lamp, Toshiba GL-10 (10 W, 254 nm), a Chemcosorb 5-ODS-UH column (150 x 4.6 mm I.D.), CLD-lOA detector (Shimadzu), a Rikadenki R-61 recorder. PTFE tubing (6.0 m x 0.5 mm I.D., GL Sciences, Tokyo) coiled around the ultraviolet lamp as the on-line for the UV radiation reactor. 

The separation of DIB derivatives of morphine and IS were performed using an HPLC system (Shimadzu, Kyoto, Japan) consisting of two pumps (LC-lOATvp) with a system controller (PX-8010), a recorder (FBR-2), a FL detector (RF-550) set at Xex=355 nm and Xem=486 nm, and a Rheodyne 7125 injector (Cotati, CA, USA) with a 20-pL sample loop. In plasma analysis, the mobile phases used were a mixture of acetonitrile-0.1 M acetate buffer (pH5.4) (50 50, v/v, MPl) with a flow rate of 1.0 mL/min and acetonitrile (MP2). The separation program was set as follows the flow rate of MP2 was set at 0 mL/min from 0 to 29 min, rapidly... 

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