Sample preparation automation

HPLC is extremely useful in monitoring and optimizing industrial processes. Conventional process monitors measure only bulk properties, such as the temperature and pressure of a reactor, while HPLC permits continuous realtime monitoring of consumption of starting materials, product composition, and impurity profile. There are a number of new initiatives relevant to HPLC for process monitoring, including sample preparation, automation, miniaturization, and specialized detectors. 

Sample preparation Automated SPE by ASPEC system. Condition a C18 Clean-Up SPE cartridge (CEC 18111, Worldwide Monitoring) with 2 mL MeOH then 2 mL water. 1 mL Plasma + 1 mL 400 ng/mL protriptyline in water, vortex, add to SPE cartridge, wash with 3 mL water, wash with 3 mL 750 mL/L methanol. Elute with three aliquots of 300 p-L 0.1 M ammonium acetate in MeOH. Add 0.5 mL 0.5 M NaOH and 4 mL 50 mL/L isopropanol in heptane to eluate, mix thoroughly. Allow 5 min for phase separation. Remove upper heptane phase and add it to 300 p,L 0.1 M phosphoric acid (pH 2.5), mix, separate, iiyect a 100 piL aliquot of the aqueous phase. 

Methods involving high resolution protein separation, paralleled sample preparation, automation of experimental processes and of database comparison, as well as powerful and specific visualisation tools need to be developed and integrated [138, 3]. 

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). 

Compatibility physieal influenee with tool ehemieal methods of sample preparation and the stage of determination based on any prineiple of an analytieal signal generation, the opportunity of automation of a sample preparation stage, eontrol, modeling of eonditions of analytieal proeess opens prospeets for their use in the analysis of food-stuffs, environment objeets, geologieal samples, ete. 

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). 

Although SFE and SFC share several common features, including the use of a superaitical fluid as the solvent and similar instrumentation, their goals are quite distinct. While SFE is used mainly for the sample preparation step (extraction), SFC is employed to isolate (chr-omatography) individual compounds present in complex samples (11 -15). Both techniques can be used in two different approaches off-line, in which the analytes and the solvent are either vented after analysis (SFC) or collected (SFE), or on-line coupled with a second technique, thus providing a multidimensional approach. Off-line methods are slow and susceptible to solute losses and contamination the on-line coupled system makes possible a deaease in the detection limits, with an improvement in quantification, while the use of valves for automation results in faster and more reproducible analyses (16). The off-line... 

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). 

R. Herraez-Heruandez, A. J. H. Eouter, N. C. van de Merbel and U. A. Th Brinkman, Automated on-line dialysis for sample preparation for gas cliromatogruphy determination of benzodiazepines in human plasma , 7. Pharm. Biomed. Anal. 14 1077-1087 (1996). 

Multidimensional liquid chromatography encompasses a variety of techniques used for seunple separation, cleanup and trace enrichment [12,279-289]. A characteristic feature of these methods is the use of two or more columns for the separation with either manual or automatic switching by a valve interface of fractions between columns. These techniques require only minor modification to existing equipment, and of equal importance, enable the sample preparation and separation procedures to be completely automated. 

The conventional analytical process is comprised of sampling — sample preparation —> analysis —> calculation —> approval of results — report — decision.93 The introduction of productivity measurements to focus attention on continuous improvement and improving the reliability of assays to eliminate re-analysis can aid in re-engineering the process for greater efficiency.93 Automation is another important aspect of improving efficiency.94 The rate-limiting steps in many industrial laboratories, however, may precede or... 

---