Solvent programmer

LC-MS is now a nature technology and operation of an LC-MS system is no longer the realm of an MS specialist. The proper choice of the LC-MS mode to be used in a specific situation depends on analyte class, sample type and problem (detection, confirmation, identification). On-line LC-MS is used more for specialised applications than for general polymer or rubber compound analysis. This derives from the fact that LC-MS method development (column, solvent system, solvent programme, ionisation mode) is rather time consuming. LC-MS (in particular with API interface) enables analysis of a wide range of polar and nonvolatile compounds which cannot be analysed by GC (icf. Scheme 7.7). 

D, detector W, waste T1 and T2, oven COM, computer Pro, solvent programmer Pri, printer INT, integrator or recorder. 

Liquid chromatographic separations were performed on a Waters Model ALC/GPC 204 liquid chromatograph equipped with two model 6000 pumps, a model 660 solvent programmer, and a model 440 dual UV absorbance detector. 

HPLC and Isolation of Mutagenic Fractions. Analytical and semipreparative reverse-phase HPLC separations were performed by using a water-to-acetonitrile linear gradient (J2). Separations were carried out on a Hewlett Packard Model 10084 B equipped with an automatic sampling device, a solvent programmer, a variable absorbance detector, and an automatically steered fraction collector. The instrument was fitted with a 3.9-mm X 30-cm prepacked analytical column of 10-/zm silica particles bonded with octadecylsilane (Bondapack-Cis) for analytical scale. For semipreparative scale separations, the HPLC was fitted with a 7.8-mm X 30-cm prepacked column packed with 10-/xm silica particles bonded with octadecylsilane. Samples for HPLC were injected at volumes of 20 /xL (flow rate 1 mL/min) and 80 /zL (flow rate 4 mL/min), and the absorption was measured at 254 nm. Fractions... 

Instrumentation. The HPLC equipment consisted of two Model 740 solvent delivery systems combined with a Model 744 solvent programmer, Model 714 pressure monitor and a Model 755 sample injector (all from Spectra-Physics, Santa Clara, CA). The column used was 25 cm x 3 mm i.d. stainless steel tube packed with either Spherisorb silica 5 y or Spherisorb ODS 5 y. Detection was made with a Schoeffel Instrument Corporation (Westwood, NJ) Model SF 770 spectromonitor. Peak areas were measured by the cut and weight method. Radioactivity was measured by direct measurement in a Searle Model 1185 Automatic Gamma System. 

Figure 6. Effect of pH on anion exchange of IAA, Column — Vydac AX — TP (10p.m) 3.9 mm ID X 20 cm, flow = 2.0 cm3 min1, mobile phase = 0.1 m, Naff2P04 — Na HPO( buffer. Pump = Waters Associates 6000A, solvent programmer, Waters Associates 600.

Liquid Chromatograph. The liquid chromatograph was comprised of a Waters 660 Solvent Programmer, two Waters 6000A pumps, a Waters U6-K Injector and a Waters 440 absorbance detector (254 nm). Whatman micro-capillary tubing (0.007" ID) was used to transfer the HPLC column effluent from the 254 nm absorption detector to the fluorescence detector. 

Solvent System 78% Methanol/22% Water to 95% Methanol/5% Water Time Twenty (20) Minutes Gradient Concave (Curve 8 on Model 660 Solvent Programmer)... 

Instrumentation was a Waters Associates HPLC system including two Model 6000A pumps, a Model 440 UV detector fixed at 254 nm, a Model 660 solvent programmer and a Model U6K injector, A Vydac 201 TP reverse phase column (10 micron C—18 packing, 4,6 mm ID x 25 cm) was used throughout. 

Fig. 5. Elution profiles obtained for the tryptic digest peptides of hemoglobin A using three distinct gradient shapes (number 3,6, and 8 on the Waters M660 solvent programmer). In each case, two /u-Bondapak C, columns were connected in series, a flow of 1.7 ml/min was used, and a 30-min linear gradient was generated from solvent A (0.phosphoric acid, pH 2.2) and solvent B (SOOt acetonitrile-0.1% phosphoric acid, pH 2.2). Reprinted with permission from Bishop et al. (5. ). Copyright by Marcel Dekker, Inc., New York.

The radio-HPLC equipment considered of 2 Waters model 6000 A pumps, a Waters 660 solvent programmer, a Waters U6K injector, a Varian Varichrom UV-VIS spectrophotometric detector, a FMI LB 5031 scintillation cocktail pump, a Berthold Radioactivity Monitor LB 504 fitted out with an 800-pl flow-cell and a Spectra-Physics SP 4100 computing integrator. Dried extracts were dissolved in minimal amounts of dimethylsulphoxide for injection. 

Minute consumption of developing solvent Programmable operating system. 

Mobile phase solvent A—acetonitrile solvent B—2mM KH2PO4. Equipment gradient system with solvent programmer and variable wavelength detector. 

Fig. 9. Waters Model 660 solvent programmer, a, a = solvent reservoirs, b, b = dual-head pumps, c, c = pressure sensors, d = solvent programming manifold, e = high-pressure noise filter, f = to column.

The Spectra Physics Chromatronix Model 744 solvent programmer similarly uses... 

On the DuPont Model 830 gradient elution accessory, Micromeritics Model 7OD0 gradient system, Perkin-Elmer Model 601 gradient system, Spectra-Physics Chromatronix Model 744 solvent programmer, Waters Model 660 sol vent prograimer,... 

A Waters Associates ALC/GPC-2 4i( instrument with 6000A solvent delivery system, 660 solvent programmer, 71 OB WISP auto-injection system and a Perkin Elmer LC75 variable UV absorbance detector was used for the HPLC analyses. All analyses were run... 

Use the solvent programmer to establish the initial solvent running conditions, then initiate the run according to the specifications for respective punfication steps (see Sections 3.2.2., 3.2.3., and 3.2.4.). 

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