Automated cartridge

M Hedenmo, BM Eriksson. On-line solid-phase extraction with automated cartridge exchange for liquid chromatographic determination of lipophilic antioxidants in plasma. J Chromatogr 692 161—166, 1995. 

The automation of the use of disposable cartridges for solid-liquid extraction connected directly with a liquid chromatograph poses major techical problems which are, however, lessened by robotics. Although several partly automatic systems have been described [23-26], there is only one really completely automated system, which was reported recently [27]. It is an automated cartridge exchange module combined with a low-cost purge pump, a solvent selec-... 

Carbohydration and polyethylene glycol linkers were combined with chemoselective conjugation to optimize the pharmacokinetics of the peptides investigated. Oxime formation was successfully adopted for chemoselective F-labeling of an aminooxy-modified affibody (Namavari et al. 2008) and a suitable derivative of the hormone leptin (Flavell et al. 2008). Recently, the [ F]FBA synthesis was automated and yielded [ F]FBA after 45 min in radiochemical yields of 54% and radiochemical purity of >99% after automated cartridge purification (Speranza et al. 2009). 

Solid phase extraction (SPE) is a very simple, rapid and reproducible cleanup technique that is now widely accepted as an alternative to the time-consuming liquid-liquid extractions. Additionally, SPE uses relatively small volumes of solvents, and is easy to automate. It is available in a number of different formats, including cartridges, disks, loose material, well plates or SPME using film-coated capillaries. SPE can be considered as an extraction technique when used for isolation and concentration or a cleanup technique when used to remove co-extractives from solvent extracts. The use of SPE for cleanup is discussed later. 

ASPEC Automated sample preparation with extraction cartridges... 

Sample preconcentration was performed by means of an automated on-line SPE sample processor Prospekt-2 (Spark Holland, Emmen, The Netherlands). Oasis HLB cartridges (Waters, Barcelona, Spain) were used to preconcentrate cannabi-noids present in the water samples whereas isolation of the rest of the compounds was done in PLRPs cartridges (Spark Holland). Before extraction, influent samples were diluted with HPLC water (1 9, v/v) to reduce matrix interferences and to fit some analyte concentrations, e.g., cocaine (CO) and benzoylecgonine (BE), within the linear calibration range. A sample volume of 5 mL was spiked with the internal standard mixture (at 20 ng/L) in order to correct for potential losses during the analytical procedure, as well as for matrix effects. Elution of the analytes to the LC system was done with the chromatographic mobile phase. 

Syringe-barrel cartridges, disk-holders, plastic pipette-tips, well plates vacuum manifolds for semiautomatic batch processing fully automated autosamplers, xyz liquid handlers and robot-controlled work stations. 

Application of SPE to sample clean-up started in 1977 with the introduction of disposable cartridges packed with silica-based bonded phase sorbents. The solid phase extraction term was devised in 1982. The most commonly cited advantages of SPE over liquid-liquid extraction (LLE) as practiced on a macroscale include the reduced time and labor requirements, use of much lower volumes of solvents, minimal risk of emulsion formation, selectivity achievable when desired, wide choices of sorbents, and amenability to automation. The principle of operation consists of four steps (1) conditioning of the sorbent with a solvent and water or buffer, (2) loading of the sample in an aqueous or aqueous low organic medium, (3) washing away unwanted components with a suitable combination of solvents, and (4) elution of the desired compound with an appropriate organic solvent. 

Commercially available fully automated online SPE systems include Prospekt, Prospekt-2, and Symbiosis systems (Spark Holland, the Netherlands) and Merck s OSP-2 (Darmstadt). Figure 10.2 shows a Symbiosis (Kuklenyik et al. 2005) two-cartridge, single analytical column online SPE... 

Automated online SPE LC systems are used extensively for environmental assays. Trays of SPE cartridges and autosampler can be used in the field. Water samples are preconcentrated trays of SPE cartridges loaded with analytes are brought to the laboratory and mounted onto an online SPE LC/ MS/MS system for analysis. Prospekt and Symbiosis systems were used for monitoring herbicides and transformation products (Hogenboom et al. 1998,1999a and b Lopez-Roldan et al. 2004 Kato et al. 2003 Lacorte and Barcelo 1995 Ferrer and Barcelo 1999,2001 Riediker et al. 2002), phenols... 

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