Sampling, automation fundamentals

Wells, D. A. and Lloyd, T. L., Automation of Sample Preparation for Pharmaceutical and Clinical Analysis, In Sampling and Sample Preparation for Field and Laboratory Fundamentals and New Directions in Sample Preparation, Pawliszyn, J., Ed., Vol. XXXVII, Elsevier Science, Amsterdam, Netherlands, pp. 837—868, 2002. 

Automated methods frequently exhibit remarkable performance not only in terms of sample throughput and cost, but in relation to the quality of results, especially in relation to repeatability and reproducibility. Several systems are currently available that enable simple automation of manual gestures these include automatic titra-tors, pH-meters with a circulating cell, etc., and involve approaches that are not fundamentally different to the corresponding manual method. These techniques are not, however, described in this chapter, nor are gas and liquid chromatography and capillary electrophoresis, automated techniques, that may be present but are not routinely used in oenological laboratories. 

As in any chromatography technique, one can break down the separation process to its two most fundamental aspects adsorption and elution. On a more practical level, the execution of an IMAC experiment involves hve discrete steps which can be readily automated column equilibration (charging of the gel), sample loading, removal of unbound material (washing), elution, and regeneration. 

An excellent feature of the NQR thermometer is that the thermometric property involved is a fundamental property of a substance, a unique frequency-temperature relationship that must be established only once and is always thereafter applicable for that substance. Thus, once the frequency-temperature relationship has been determined for a suitable sensor material, such as KClOg, that calibration will apply to all other samples of that material provided that the material has been prepared with consistent purity. This, then, eliminates the need to calibrate each thermometer individually as is required for most practical thermometers. Another advantage is that frequency can be easily and accurately measured and the thermometer can be easily made a part of an automated system for temperature monitoring and control. Through the use of standard frequency broadcasts by NBS, the accuracy of the frequency counter used in making measurements can be easily checked. 

The advances in sample fractionation methods, sample derivatization approaches, and the instrumentation of GC and GC/MS, in particular, are fundamental to metabolic profile research. Biological variation that is inherent to the samples of physiological fluids or tissues should not be obscured by an excessive imprecision of measurement techniques. Thus, reliable sampling and sample treatment procedures (including as much automation as is feasible) should precede the use of sophisticated GC and GC/MS techniques. 

The fundamental strategy was the same, but the process was automated. Each of the dideoxy nucleotides was tagged with a different fluorescent dye. The four separately reacted mixtures were combined and electrophoresced in a single lane using a robotically controlled sequencer, which can analyze 96 samples simultaneously. As each fragment reached the bottom of the electrophoresis lane, its dideoxy nucleotide was identified from its characteristic fluorescence. Automatic sequencers can sequence 5 x 10 bases per day compared to 3 x lO per year using the manual methods described in Fig. 8-21. 

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