Instrumentation chromatography

As mentioned above, instrumentation designed for ion chromatography is constructed so that all wetted surfaces are composed of inert materials such as PEEK, KelE and Teflon. Eor short-term operation, it is possible to make use of standard HPLC equipment. But in this case it is 

In HPLC, where methods are nearly exclusively based on generic reversed phase columns, methods can generally be transferred from one column to another with minimal modification. In ion chromatography, such is rarely the case. Instead, methods for specific analyte ions are 

The second stationary phase architecture (electrostatic agglomerated films on nonporous substrates, EANPS) was one of the first types of 

FIGURE I Schematic diagram illustrating the construction of an anion exchange latex coated, surface-sulfonated, nonporous cross-linked polyethylvinylbenzene-divinylbenzene resin bead. 

Electrostatic Agglomerated Ultra-Wide-pore Substrates 

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To find explosives Gas analyzers, chromatography instruments, drift-spectrometers, neutron defectosopes, nuclear-magnetic and nuclear-quadrupole resonant instruments... 

The Waters pump was one of the first twin headed LC pumps to be produced and was probably the major factor in establishing Waters fine reputation in the field of liquid chromatography instrumentation. 

Foncanlt, A.P. and Chevolot, L., Connter-cnrrent chromatography instrumentation, solvent selection and some recent applications to natural product purification, J. Chromatogr. A, 808, 3, 1998. 

Validations fall into two types prospective and retrospective. In prospective validation (see flow chart in Figure 2) the validation is done in a sequential manner, involving installation qualification and operational qualification (IQ/OQ) of equipment (e.g., chromatography instrumentation or column hardware). Appropriate calibrations accompany the IQ/OQ. Process qualification, or PQ, involves formal review and approval of a PQ protocol, execution of this protocol, and issuance of a formal PQ report which includes data analysis and recommendations (i.e., approval/certification of the process). If the process is not approved, the report may recommend a redesign or redoing of the validation protocol and, in some cases, a return of the process to process development for further optimization. 

Tipler, A. (1993). Gas chromatography instrumentation, operation, and experimental considerations. In Gas Chromatography A Practical Approach, ed. Baugh, P.J., Oxford University Press, Oxford, pp. 15-70. 

FIGURE 10.21 An illustration of a mass spectrometer coupled to a chromatography instrument. 

For many years, the concept of the conductivity detector could not work, however. Ion chromatography experiments utilize solutions of high ion concentrations as the mobile phase. Thus, changes in conductivity due to eluting ions are not detectable above the already high conductivity of the mobile phase. This was true until the invention of so-called ion suppressors. Today, conductivity detectors are used extensively in HPLC ion chromatography instruments that also include suppressors. 

Although changes in temperature, whether of the laboratory or the oven, the injection port of a gas chromatography instrument, or any other con-... 

The solution behavior of poly(amic acids) was until recently, probably the least understood aspect of the soluble polyimide precursor. However, the advent of sophisticated laser light scattering and size exclusion chromatography instrumentation has allowed elucidation of the solution behavior of poly(amic adds). In the early days of polyimide chemistry, when most molecular weight characterization was based on viscosity determinations, a decrease in viscosity was associated with molecular weight degradation [15, 28, 29]. Upon combination of the two monomers an increase in the viscosity to the stoichiometric equivalence point is observed, followed by a decrease in the solution viscosity as a... 

Ion chromatography instruments have the same components as those found in HPLC (see Fig. 4.1). They can exist as individual components or as an integrated instrument. The components of the system are made out of inert materials because the mobile phase is composed of acids or alkaline entities that can be highly corrosive. Instruments that operate in the isocratic mode are used more often than those allowing gradient elution. 

An overview and discussion is given of literature methods published after 1989 devoted to the ion-interaction chromatographic determination of inorganic anions. Seventy references are quoted. Ion-interaction chromatography makes use of commercial reversed-phase stationary phase and conventional high-performance liquid chromatography instrumentation. The basis of the technique, the modification of the stationary phase surface, the choice of the ion-interaction reagent as well as the dependence of retention on the different variables involved are discussed. Examples of application in the fields of environmental, clinical and food chemistry are presented. The experimental conditions of stationary phase, of mobile phase composition as well as detection mode, detection limit and application are also summarized in tables. 1997 Elsevier Science B.V. 

Figure 3.1 Two-dimensional gas chromatography instrumental configurations (a) direct transfer heart-cut configuration (b) multiple parallel trap configuration (c) multiple parallel column configuration.

Since patent novelty is a somewhat abstract concept in the absence of context, it is helpful to consider another example. Gas liquid chromatography instruments... 

D. Later, B. Richter, et al., Capillary supercritical fluid chromatography instrumentation and applications, Am. Lab., (August 1986). 

There are two important methods in which ions or, less often, neutral compounds in solution (often containing formic acid) have their solvent molecules stripped by evaporation, with simultaneous ionization leaving behind the ions for mass analysis. Coupled with liquid chromatography instrumentation, these methods have become immensely popular. 

N. M. Djordjevic, P. W. J. Eowler, and F. Houdiere, High temperature and temperature programming in high-performance liquid chromatography instrumental considerations, 7. Microcol. Sep. 11 (1999), 403-413. 

Gas Chromatography instrument with detector interface only... 

High Performance Liquid Chromatography instruments with integral PC control system and local printer... 

HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY INSTRUMENTATION QUALIFICATION... 

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