Computer HPLC method

Procedures used vary from trial-and-error methods to more sophisticated approaches including the window diagram, the simplex method, the PRISMA method, chemometric method, or computer-assisted methods. Many of these procedures were originally developed for HPLC and were apphed to TLC with appropriate changes in methodology. In the majority of the procedures, a set of solvents is selected as components of the mobile phase and one of the mentioned procedures is then used to optimize their relative proportions. Chemometric methods make possible to choose the minimum number of chromatographic systems needed to perform the best separation. 

Introduction to HPLC, CLC-10 and HPLC Method Development, CLC-20, (Computer-based Instruction), Savant, Eullerton, CA, http //www.savant4training.com/savant2.htm. 

There is some disagreement within the AI community as to what qualifies a computer program to be called an "expert system". We use the term to describe a program which has the following characteristics 1) The program performs some task (e.g., HPLC methods design) which requires specialized human expertise. This human expertise often takes the form of heuristics (empirical rules of... 

The goal of ECAT is to provide assistance to the user of a chromatograph in the development of an HPLC method. To do this, one must specify the tasks performed in developing an analytical method. The computer performs these tasks by processing information. In ECAT we are calling the collection of information specific to a task a Module. The modules and information flow which will be needed for the completely implemented ECAT are shown in Figure 2. 

N. G. Mellish, Computer-assisted HPLC method development in a pharmaceutical laboratory, LC-GC, 9 845 (1990). 

Comparison of various modes and phase systems fim analytical HPLC 1.4.7 Computer-assisted optimisation of HPLC methods... 

A very interesting task would be automatic measurement of the product and the calculation of production rates. This would allow automatic optimization of the process by a computer program that varies all relevant parameters, probably by multiparameter analysis, to find the best production conditions. As long as there are no product sensors available, the main problem may be the time necessary for the measurement of an automatically taken sample. However, the use of HPLC methods can give accurate results within 20 min, and high-performance capillary electrophoresis (HPCE), with an analysis time of 5 min, could be introduced (Beckman PIACE 2(X)0, E. Wasserbauer, personal communication and James et al, 1994). Nonetheless, further development is necessary before these methods can be used routinely for automatic fermentation analysis. 

This chapter provides an overview of modern HPLC method development and discusses approaches for initial method development (column, detector, and mobile phase selection), method optimization to improve resolution, and emerging method development trends. The focus is on reversed-phase methods for quantitative analysis of small organic molecules since RPLC accounts for 60-80% of these applications. Several case studies on pharmaceutical impurity testing are presented to illustrate the method development process. For a detailed treatment of this subject and examples of other sample types, the reader is referred to the classic book on general HPLC method development by L. Snyder et al.1 and book chapters2,3 on pharmaceutical method development by H. Rasmussen et al. Other resources include computer-based training4 and training courses.5... 

Column and high performance liquid chromatography (HPLC) methods for measurement of solubility, octanol-water partition coefficient, and vapor pressure which are replacing the older equilibrium methods tend to underestimate aqueous solubility and vapor pressure and tend to overestimate the octanol-water partition coefficient. The standard deviation for both the equilibrium and dynamic systems are similar, but calibration between systems is necessary to insure that they agree. The range of errors for both types of measurement as mentioned in the literature are well within the range predicted by the computer-simulated error distributions generated in this report. The measurement error... 

Galushko, S. et ah, Chromsword Software for Automated and Computer-Assisted Development of HPLC Methods, in HPLC Made to... 

Snyder, L.R. and Wrisley, L. (2006) Computer-Facilitated HPLC Method Development Using DryLab Software, in HPLC Made to Measure, (Ed. S.Kromidas), Wiley-VCH, Weinheim. 

The fundamental components of any modern-day HPLC system are a solvent delivery system, a sample injector, a column, a detector, and a computer with the appropriate data acquisition and processing software. There are numerous HPLC methods described in the literature for isoflavones [13-25] and for the common anthocyanins, each method invokes different combinations of solvent systems, columns, and detectors. HPLC has been interfaced with a variety of detection methods such as ultraviolet/visible (UV/vis) spectrocopy and hquid chromatography-mass spectrometry (LC-MS) [21,22]. In this chapter, however, discussion is restricted to the most commonly used pairing in flavonoid analysis, that of a reverse-phase (RP-18) column and a UV/visible detector. 

Automation can generally lead to the elimination of errors and to time saving. Meanwhile, fuUy automated computer-aided method development and semi-automated optimization in HPLC have reached a remarkable level of maturity and sophistication. Through several real examples, Lloyd R. Snyder (Chapter 4.1) and Sergey Galushko (Chapter 4.2) describe the possibilities offered by the software packages DryLab and ChromSword , respectively. Michael Pf er (Chapter 4.3) compares the two software concepts from the point of view of the user, and presents a new software tool that also incorporates automatic colurrm selection. 

Computer-Facilitated HPLC Method Development Using DryLab Software... 

Computer simulation refers to the use of a computer for predictions of separation as a function of experimental conditions. In most cases, computer simulation requires two or more experimental runs with a given sample, in order to calibrate the computer prior to making predictions. Computer simulation can be used in H PLC method development to select optimum final conditions for the separation of a given sample, so that fewer actual experiments are required and better HPLC methods result Ideally, computer simulation should (a) allow for the simultaneous variation of as many as two experimental conditions that affect separation selectivity, (b) be applicable for both isocratic and gradient elution, and (c) be able to predict the further effect on separation of changes in flow rate, column dimensions and particle size. 

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