Chromatographic hardware

Module 6, Column Diagnosis (COLDIAG). This module uses chromatographic parameters such as efficiency, asymmetry, retention time, selectivity and operating pressure, to detect failures of the column or other chromatographic hardware. Table II lists the types of column failure which the module can currently handle. Note that the module will also correctly diagnose some problems which are NOT column malfunctions but which might be interpreted as such by a user. 

The next step is column selection. Many factors contribute to the chromatographic results that are obtained on a given sample. Some of these are related to the instrument, and others are operational parameters. The column is in both ways important. The column as part of the chromatographic hardware is a design parameter which should be selected according to the needs of individual laboratories. Operational parameters, including column temperature and carrier flow rate, both of which may exercise profound influences on column behavior must be selected by the operator, considering the application as well as the characteristics of the column. 

Except for certain library routines used to drive the interface hardware and some system specific routines from the system library, all of the routines are written in a dialect of FORTRAN IV and they are sufficiently modular and portable to be adaptable to other combinations of computers and chromatographs. 

The Chem Master Workstation is a gas chromatography and gas chromatography-mass spectrometry data-processing system that speeds the flow of data through the laboratory and provides essential quality-assurance and quality-control review. It is a PC-based integrated hardware/ software system that converts gas chromatographic and gas chromatography-mass spectrometric data into reliable analytical reports. 

When using NMR as a detector for online separations, additional consideration must be given to how the sensitivity is affected by the movement of nuclei past the detector cell. Aside from the physical hardware setup, the chromatographic and spectroscopic parameters also play a role in the quality of the resulting data. Flow rate, solvent composition, and residence and acquisition times can be optimized to provide optimal results. NMR sensitivity and chromatographic resolution tend to have an inverse relationship with respect to online LC-NMR experiments. By slowing the flow rate, more scans can be acquired for a particular analyte in the flow cell, but... 

Note As is often the case, the HPLC system will be under computer control, which is likely to be part of a data-handling system. Since the data generated from the OQ hardware tests typically require chromatographic data handling, the data-handling software should be validated beforehand. The data-handlingfLC control software installation and IQ/OQ implementation, which are not addressed in this chapter, may take a considerable amount of time. This is often the case since this process typically involves an initial client/server implementation. 

The application of HPLC in routine environments, like pharmaceutical, food, or environmental analysis and particularly quality assurance, makes not only great demands on the robnstness of HPLC hardware, comprising pumps, column thermostats, and detection units, bnt in addition to the column reproducibility. Column reproducibility can be investigated at different levels of complexity Run-to-run reproducibility compares consecutive chromatographic runs, whereas long-term stability describes the column variance over several hundreds of injections. Column-to-column (batch-to-batch) reproducibility finally explores the match of independently fabricated chromatographic columns. Column characteristics that are routinely consulted for the determination of the robustness are retention, selectivity, column efficiency, and peak symmetry. 

The retention equation allows us to understand the first major difference between the CCC solute retention and the retention obtained with any other chromatographic technique. Usually, in chromatography, the same solute mixture separated on the same column and using the same mobile phase produces the same chromatogram. If it is not the case, it is a sign of column wearing or problems in the hardware (pump, detector, or injector). 

Qualification of equipment hardware (e.g., a spectrophotometer or liquid chromatograph). 

Supercritical fluid chromatography (SFC) is a relatively recently developed chromatographic technique. Because of its ability to deal with compounds that are either polar or of high molecular weight, much attention has recently focused on applications of SFC to the analysis of different analytes using a variety of fluids or fluid mixtures to provide differing solvent capabilities and select vities. As a result there is a large amount of research currently underway both in SFC method development and in hardware development. 

---