Rheodyne injection system

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. 

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 As in other types of laboratory, septum type injection systems in environmental laboratories have long been superseded. 

In the FIA system, peristaltic pnimp (ISMATEC ITC, Switzerland) 0.50 mm i.d. PFTE tubing was used to propel the samples and reagent solutions. Samples were injected into the carrier stream by a 7125 model stainless steel high pressure Rheodyne injection valve provided with a 20 )xL loop. The absorbance of the coloured complex formed (Xmax 415 nm) was measured with a UV-Visible spectrophotometer equip>p)ed with a flow-through micro cell (Spectra SYSTEM UV 3000 HR, Thermo Separation Products, USA), and connected to a compniter incorporated with a PCI000 software programme. 

As in the previous work, the flow injection system consisted of a Cole Parmer Mas-terflex peristaltic pump, Rheodyne 7125 injector, Bioanalytical System (BAS) TL-5A flow through electrochemical cell and either an IBM EC/230 or a BAS CV 37 potentiostat. These instruments respectively are designed for use with an electrochemical detector for liquid chromatography and for low current measurements such as with ultramicroelectrodes. A pulse dampener was also included in the flow system. 

High pressure liquid chromatography (HPLC) Waters (Mildford, MA) 6000A solvent delivery system, fitted with a Rheodyne injection valve and equipped with a Waters 484 tunable absorbance detector. 

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). 

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. 

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. 

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. 

Inc. System (two model 6000A pumps model 440 UV detector with a 254 filter model 680 gradient controller model 746 data module and a RCM 8 X 10 cm Radial Compression Cartridge Holder) was used for high pressure liquid chromatography. Injections were made with a model 7125 Rheodyne injector. 

The extracts were analyzed using a liquid chromatography system, consisting of a Jasco (Tokyo, Japan) PU-980 pump, a Rheodyne (California, USA) injector (injection volume 20 pi) and a Chrompack (the Netiierlands) Chromsphere 100 mm x 3 mm I.D C18 column packed with 5 pm particles with... 

One system we used for this work was comprised of four 30-cm 100-A /x-Styragel columns (from Waters Associates) connected in series with a Rheodyne Model 7105 injector valve and a Varian 4200 syringe pump that maintained a constant flow of either 1 or 2 mL/min. At 1 mL/min the overall resolution efficiency was about 15,000 theoretical plates and the run time was about 50 min. By doubling the flow rate, the run time was cut in half with only a slight loss of column efficiency. The pressure required for a flow rate of 2 mL/min was usually about 1200 psi. Tetrahydrofuran (UV grade from Burdick and Jackson Laboratories) was used as the eluting solvent. The amount of sample solution injected into the system varied from 10 /xL to 500 /xL. 

The HPLC apparatus consisted of a three-head (120°) chromatographic pump (Merck LC 21B), connected to a Rheodyne 7126 injection valve (Sample loop 100 pi). A variable-wavelength UV-Visible detector (Merck-LC 313) and the gradient system were connected to an Epson QX-10 computer. The chromatographic signal was monitored, integrated and stored by the computer. These various components were obtained from Merck-Clevenot (Nogent-sur-Marne, France). 

Fig. 2. Flow diagram of the FI A system used. R reagent carrier solution (1x10 M Morin in ethanol water (4 96 v/ v) in 0.1 M HAc/ Ac buffer (pH 4.50)), P, Peristaltic pump, S Rheodyne sample injection valve, RC reaction coil (50 cm long, 0.5 mm i.d), D spectrophotometric detector Xmax = 415 nm), W waste, C computer, P printer.

The flow FFF systems are characterized by the use of a second pump to drive carrier across the channel thickness this setup provides the field that induces migration of sample toward the accumulation wall. The Flow I system was operated with an Isochrom EC pump (Spectra-Physics Inc., San Jose, CA) as the channel flow pump and a pulseless syringe pump (built in-house) as the cross-flow pump. Sample was injected via a Valeo injector (Valeo Instruments co., Houston, TX) with a 20-pL loop, and the eluted sample was detected at 254 nm with a UV-visible detector (UV-106, Linear Instruments, Reno, NV). The peripheral equipment employed in How II and ni consisted of a Kontron model 410 channel flow pump, a syringe pump serving as the cross-flow pump, a Rheodyne (Cotati, CA) model 7010 pneumatic-actuated injection valve, and a model 757 Spectroflow UV-vis detector from Applied Biosystems (Ramsey, NJ) operated at 254 nm. 

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