Line cleaning automation

An automated supercritical fluid extraction and in-line clean-up system has been developed for organochlorine and organophosphate pesticide residues contained in fats (Hopper, 1999). 

Ascalone, V. Flaminio, L. Automated high-performance liquid chromatography with column switching for on-line clean-up and analysis of diltiazem and metabolites in human plasma. J.Chromatogr., 1989, 495, 358-360 [plasma column-switching extracted metabolites LOD 2 ng/mL improved version of method in J.Chromatogr. 1987, 423, 239]... 

Conley, D.L. Benjamin, E.J. Automated high-performance liquid chromatographic column switching technique for the on-line clean-up and analysis of drugs in topical cream formulations. J.Chromatogr., 1983, 257, 337-344... 

Instrument-based extraction techniques such as supercritical fluid extraction (SEE) and pressurized liquid extraction (PEE) offer advantages because of their potential for automation, more selective isolation of residues through tuning of parameters, and on-line clean-up of samples. Their applications have been slowed by the limited number of commercially available instruments, additional extraction costs, and instrumental downtime. Although several applications have been developed using SEE and PEE, these techniques are not widely used in routine laboratories. 

Buttrick, P. (2006). Automated beer line cleaning. Brewer and Distiller, 2(8), 25-27. 

Uniformity of the rate of feed will be ensured by a constant-weight feeder density control may be automatically obtained through a measuring probe on the media-return line that adjusts delivery of the nec-essai y volume of media from the densifier or media thickener the viscosity can be controlled automatically by continuously testing a predetermined volume of return media and adjusting the divider under the drainage screen for media cleaning as needed pH control can be automated by conventional methods. 

J. A. Apffel, T. V. Alfredson and R. E. Majors, Automated on-line multi-dimensional high performance liquid chromatographic techniques for the clean-up and analysis of water-soluble samples , J. Chromatogr. 206 43-57 (1981). 

The most common (off-line) sample preparation procedures after protein precipitation are solid phase extraction and liquid-liquid extraction. Multiple vendors and available chemistries utilize 96-well plates for solid phase extraction systems and liquid-liquid extraction procedures. Both extraction process can prepare samples for HPLC/MS/MS assay. Jemal et al.110 compared liquid-liquid extraction in a 96-well plate to semi-automated solid phase extraction in a 96-well plate for a carboxylic acid containing analyte in a human plasma matrix and reported that both clean-up procedures worked well. Yang et al.111 112 described two validated methods for compounds in plasma using semi-automated 96-well plate solid phase extraction procedures. Zimmer et al.113 compared solid phase extraction and liquid-liquid extraction to a turbulent flow chromatography clean-up for two test compounds in plasma all three clean-up approaches led to HPLC/MS/MS assays that met GLP requirements. 

The Gilson Aspec automatic sample preparation system is a fully automated system for solid-phase extraction on disposable columns and online HPLC analysis. The Aspec system offers total automation and total control of the entire sample preparation process including clean-up and concentration. In addition, Aspec can automatically inject prepared samples into on-line HPLC systems. 

While automation of dissolution sampling is very convenient and laborsaving, errors often occur with these devices because the analysts tend to overlook problem areas. Sample lines are often a source of error for a variety of reasons unequal lengths, crimping, wear beyond limits, disconnection, carryover, mix-ups or crossing, and inadequate cleaning. 

Many complex (and expensive) automated multibath cleaning, rinsing and drying systems can be found in high volume production lines. For the chemical laboratory however a single small cleaning bath can be obtained at a very reasonable cost. 

In-line instruments or sensors are necessary components for automated processes. For ease of cleaning, sensors should be chosen that directly mount onto vessel nozzles or piping tees with minimum dead leg distances. Also, the instru-... 

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