Automated sampling

The quahty of an analytical result also depends on the vaUdity of the sample utilized and the method chosen for data analysis. There are articles describiag Sampling and automated sample preparation (see Automated instrumentation) as well as articles emphasizing data treatment (see Chemometrics Computer technology), data iaterpretation (see Databases Imaging technology), and the communication of data within the laboratory or process system (see Expert systems Laboratory information managet nt systems). 

W. Haasnoot, M. E. Ploum, R. J. A. Paulussen, R. Schilt and F. A. Huf, Rapid determination of clenbuterol residues in urine by high perfoi mance liquid cliromatography with on-line automated sample processing using immunoaffinity chromatography , 7. Chromatogr. 519 323-335 (1990). 

I. Fener, V. Pichon, M-C. Hennion and D. Barcelo, Automated sample preparation with exti action columns by means of anti-isoproturon immunosorbents foi the determination of phenylurea herbicides in water followed by liquid chi omatography-diode aixay detection and liquid cliromatogi aphy-atmospheric pressure chemical ionization mass spectrometiy , 7. Chromatogr. 777 91-98 (1997). 

K. Ki onkvist, M. Gustavsson, A.-K. Wendel and H. Jaegfeldt, Automated sample preparation foi the determination of budesonide in plasma samples by liquid chi omatography and tandem mass specti ometi y , 7. Chromatogr. A 823 401-409 (1998). 

Multiple cryogenic traps between the pre-column and the analytical column were developed in 1993 by Ragunathan et al. (23). These authors found that a multiple trap configuration provided the necessary resolution and automated sampling for simultaneous GC/IR and GC/MS determination of very complex mixtures. A... 

E. A. Hogendoom, G. R. van der Hoff and P. van Zoonen, Automated sample clean-up and fractionation of organochlorine pesticides and polychlorinated biphenyls in human milk using NP-HPEC with column-switching , J. High Resolut. Chromatogr. 12 784-789 (1989). 

The measurement of extreme log P/log D values (generally accepted to be below -3 and above 4) requires a disproportionate volume ratio of the aqueous and solvent phases, making it difficult to sample a reasonable amount for the concentration determination and automated sampling almost impossible. 

An exeuaple of a nodular apparatus for capillary electrophoretic separation methods, is shown in Figure 4.43 [637-639,681-684]. It Offers a choice of automated sample introduction methods with on-column detection and has a... 

Dutton, J., Hodgkinson, A. J., Hutchinson, G., and Roberts, N. B., Evaluation of a new method for the analysis of free catecholamines in plasma using automated sample trace enrichment with dialysis and HPLC, Clin. Chem., 45, 394, 1999. 

Miniaturized columns have provided a decisive advantage in speed. Uracil, phenol, and benzyl alcohol were separated in 20 seconds by CEC in an 18 mm column with a propyl reversed phase.29 A19 cm electrophoretic channel was etched into a glass wafer, filled with a y-cyclodextrin buffer, and used to resolve chiral amino acids from a meteorite in 4 minutes.30 A 6 cm channel equipped with a syringe pump to automate sample derivatization was used to separate amino acids modified with fluorescein isothiocyanate.31 Nanovials have been used to perform tryptic digests on the 15 nL scale for subsequent separation on capillary Electrophoresis.32 A microcolumn has also been used to generate fractions representing time-points of digestion from a 40 pL sample.33 A disposable nanoelectrospray emitter has been... 

Major advantages of LVI methods are higher sensitivity (compare the 100-1000 iL volume in LVI to the maximum injection volume of about 1 iL in conventional splitless or on-column injection), elimination of sample preparation steps (such as solvent evaporation) and use in hyphenated techniques (e.g. SPE-GC, LC-GC, GC-MS), which gives opportunities for greater automation, faster sample throughput, better data quality, improved quantitation, lower cost per analysis and fewer samples re-analysed. At-column is a very good reference technique for rapid LVI. Characteristics of LVI methods are summarised in Tables 4.19 and 4.20. Han-kemeier [100] has discussed automated sample preparation and LVI for GC with spectrometric detection. 

High efficiency (automated sample injection carousel)... 

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