Automated online SPE

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 systems have been applied to various phases of drug discovery. McLoughlin et al. (1997) utilized the Prospekt system in pharmacokinetic animal studies for rapid drug candidate screening. Up to 10 compounds were simultaneously monitored. The lower limits of detection were... 

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... 

Barrett Y.C. et al., 2005. Automated online SPE LC-MS/MS method to quantitate 6-beta-hydroxycortisol and cortisol in human urine. J Chromatogr B 821 159. 

Calderoli S. et al., 2003. LC-MS-MS determination of brostallicin in human plasma following automated online SPE. J Pharm BiomedAnal 32 601. 

Papadopouluo-Mourkidou E. et al., 2001. Use of an automated online SPE-HPLC method to monitor caffeine and selected aniline and phenol compounds in aquatic systems of Macedonia-Thrace, Greece. Frese-nius J Anal Chem 371 491. 

Selected data published by Patsias and Papadopoulou-Mourkidou [114] illustrate sorption s dependence on sample volume (Figure 2.36). Their research pursues development of an automated online SPE-HPLC methodology for analysis of substituted anilines and phenols. Recovery (%) was measured for numerous compounds on various polymeric sorbents, but the only data presented here are those in which a styrene-divinylbenzene polymeric sorbent was used for analysis of aniline, phenol, 4-nitroaniline, and 4-nitrophenol. Aqueous sample volumes of 5, 10, 25, 50, 75, 100, 125, and 150 mL were acidified to pH 3 before SPE. 

K. Stoob, EI.P. Singer, C.W. Goetz, M. Ruff, S.R. Mueller, Fully automated online SPE-LC-MS-MS. Quantification of sulfonamide antibiotics, neutral and acidic pesticides at low concentrations in surface waters, J. Chromatogr. A, 1097 (2005) 138. 

Hidalgo, C., Sancho, J. V., Roig-Navarro, A., and Hernandez, F., Rapid-determination of carbaryl and 1-naphthol at ppt levels in environmental water samples by automated online SPE-LC-DAD FD, Chromatographia, 47, 596-600, 1998. 

Analysis of pesticides in water was performed by fully automated online solid-phase extraction-liquid chromatography-tandem mass spectrometry (SPE-LC-MS/ MS) [25, 31]. These pesticides (a total of 22 belonging to the classes of triazines, OP, chloroacetanilides, phenylureas, thiocarbamates, acid herbicides, and anilides) were selected on the basis of previously published studies [20, 25], information gathered from the water authorities, and known use in rice crops. 

The feasibility of online SPE LC/MS/MS has been tested since the introduction of thermospray ionization. In an early research paper by Lant and Oxford (1987), a prototype online SPE LC/MS system was set up and successfully applied for the measurement of labetalol, a hypertension drug and a- and /J-adrenergic receptor, in plasma. This system was set up by coupling an advanced automated sample processor (AASP, Varian, Walton-on-Thames, UK) with a reversed-phase column, a ten-port switching valve, and an MS equipped with thermospray interface (Vestec, Houston, Texas) (Blakley et al. 1980, Blakley and Vestal 1983). 

About the analysis of pesticides, water samples were collected in amber glass bottles and transported to the laboratory under cooled conditions (4°C). Upon reception, samples were filtered (0.4-pm membrane filters) and then stored at —20°C in the dark until analysis. Analysis was performed by a fully automated multiresidue analytical method based on online SPE-LC-MS/MS [27]. 

Adaptation of SPE for automated online extraction prior to HPLC analysis 327... 

Different developed analytical method are discussed in this chapter related to the determination of illicit substances in blood (either whole blood, plasma, or serum), OF, urine, and hair. These methods take into consideration the particular chemical and physical composition of the matrix and applies each time a suitable pretreatment to remove interfering and matrix effect, to maximize recoveries and to achieve a suitable enrichment if necessary. For liquid matrices the applications of the most common techniques are considered from simple PPT to SPE and LLE the results of recent works from literature are reported and new trends as online SPE, pSPE, automated LLE (SLE) or MAE are examined. Several stationary phases have been shown to be suitable for determination of illicit drugs Cl8, pentafluorophenyl, strong cation-exchange, and HILIC columns. The trend toward fast chromatography is investigated, both UHPLC and HPLC with appropriate arrangements moreover, results obtained with different ion sources, ESI, A PCI, and APPI are compared. 

An important feature and advantage of on-line SPE, compared with off-line SPE, is direct elution of the analyte from the SPE cartridge into the mobile phase of the LC system. The time-consuming off-line steps of evaporation, reconstitution, and preparation for injection are eliminated and make the online SPE more efficient and fully automated. Since the entire volume of eluate is analyzed, maximum sensitivity for detection is obtained. Some other advantages of this on-line approach include ... 

A fully automated method, based on online SPE-LC-MS/MS analysis, has been developed for the determination of some most relevant endocrine disrupting chemicals in water samples. 

Online application of SPE methodology in combination with GC originated from coupled LC-GC, where small volumes from the EC eluent were transferred through a modified GC autosampler. Benefits are in the automation of SPE procedures. In online SPE trace-enrichment techniques the extraction cartridges are called precolumns. In this approach, small columns (1 to... 

In an online SPE configuration, extraction is done in a solid phase packed in a precolumn placed at the loop of a six-port switching valve. This method is easily automated, and preconcentration and chromatographic analysis can be done in the same run. It allows high throughput analysis, timesaving, improved precision, and accuracy. Its disadvantages are systematic errors and recovery error. It can be used in combination with GC or LC. ... 

In recent years, fully automated analysis of contaminants in water by the online coupling of SPE to EC or GC instmmentation has received increasing attention. Besides allowing rapid analysis, in online SPE there is reduced handing of samples and the consumption of organic solvents is also reduced. In addition, the total amount of analytes extracted is introduced into the chromatograph and, consequently, sample volume can be drastically reduced. 

Online SPE-LC can be easily automated by using commercially available devices as Prospekt (from Spark Holland) or OSP-2 (Merck), which have the capability to switch to a fresh disposable precolumn for every sample. These systems improve the productivity since the next sample is automatically prepared while the previous sample is being analyzed. 

In comparison to automated online trace enrichment on precolumns (SPE-LC), one of the most favorable aspects of automated sample processing using LC-LC is the utilization of the separation power of the first column (C-1). In fact, the application range of the LC-LC technique will be determined by the separation power of the first column low resolution favors multiresidue methods, while high resolution leads to methods for single analytes or a group of compounds with fairly similar properties. 

Multidimensional chromatography is one of the best options to prevent unwanted coelutions of analytes with other matrix components present in a variety of complex samples, and also to incorporate automated online sample preparation in the analytical process. Nowadays, well-developed methodologies already exist using multidimensional modes as LC-LC or SPE-LC in combination with spectroscopic or electrochemical detection for the selective and sensitive determination of many analytes, mainly in the biomedical, pharmaceutical, environmental, and food fields. 

A typical approach in environmental analysis is an integrated system called SAMOS, which enables the automated, vmattended analysis of filtered 100 ml sinface water samples by means of online SPE and subsequent gradient-LC-UV detection. Any... 

For solid-phase extraction, the offline procedure, based on sample pretreatment on disposable SPE cartridges, and a totally automated online procedure, based on column switching, have been developed. The column switching procedure involves the use of a polystyrene-divinylbenzene column for sample concentration and cleanup. 

---