Solid-phase extraction methods development

Hennion M., 1999. Solid-phase extraction Method development, sorbents, and coupling with liquid chromatography. J Chromatogr A 856 3. 

M.-C. Hennion, Solid-phase extraction method development, sorbents and coupling with liquid chromatography , J. Chromatogr. 856 3-54 (1999). 

TD Parker, DT Rossi, DS Wright. Design and evaluation of an automated solid-phase extraction method-development system for use with biological fluids. Anal Chem 68 2437-2441, 1996. 

DT Rossi. Automating solid-phase extraction method-development for biological fluids trends and applications in bioanalysis, LC-GC 17 S4—S8, 1999. 

Chen XH, Franke JP, Ensing K, Wijsbeek J, De Zeeuw RA. 1993. Pitfalls and solutions in the development of a fully automated solid-phase extraction method for drug screening purposes in plasma and whole blood. J Anal Toxicol 17 (7) 421-426. 

Nichkova, M. and M.R Marco. 2005. Development and evaluation of C18 and immunosorbent solid-phase extraction methods prior to immunochemical analysis of chlorophenols in human urine. Anal. Chim. Acta 533 67-82. 

An HPLC-DAD method was developed for the separation and the determination of flavonoid and phenolic antioxidants in commercial and freshly prepared cranberry juice.Two sample preparation procedures were used with and without hydrolysis of the glycoside forms of flavonoids carried out by the addition of HCl in the step prior to solid-phase extraction (SPE). The flavonoid and phenolic compounds were then fractionated into neutral and acidic groups via a solid-phase extraction method (Sep-Pak Cig), followed by a RP HPLC separation with gradient elution with water-methanol-acetic acid and a detection at 280 and 360 nm. A comparison of the chromatograms obtained for extracts prepared with and without hydrolysis showed that flavonoids and phenolic acids exist predominantly in combined forms such as glycosides and esters. In a freshly squeezed cranberry juice, for instance, 400 mg of total flavonoids and phenolics per liter of sample was found, 56% of which were flavonoids. Quercetin was the main flavonoid in the hydrolyzed products, where it accounted for about 75% of the total flavonoids, while it was absent in the unhydrolyzed products. 

Lindstrom, A., Albertsson, A.C. and Hakkarainen, M. (2004) Development of a solid-phase extraction method for simultaneous extraction of adipic acid, succinic acid and... 

A fourth experiment would be an evaluation of precision and recovery at one to four concentration levels (n — 6 to 24 plus a recovery standard), plus recovery of an internal standard (n — 3 plus recovery standard). Therefore, as a minimal method development exercise, 60—70 spiked samples would be prepared and extracted within 1 day. The experiments need to be performed sequentially because the results from each will impact how subsequent experiments are designed. Selectivity is assessed through the course of the method development. The analytical chemist with access to API LC/MS/MS will spend less time on solid-phase extraction selectivity development. 

Lopez, R. Aznar, M. Gacho, J. Ferreira, V. (2002). Determination of minor and trace volatile compounds in wine by solid-phase extraction and gas chromatography with mass spectrometric detection. Journal of Chromatography A 966,167-177 Lopez, R. Gracia-Moreno, E. Gacho, J. Ferrreira, V. (2011). Development of a mixed-mode solid phase extraction method and further gas chromatography mass spectrometry for the analysis of 3-alkyl-2-methoxypyrazines in wine. Journal of Chromatography A 1218, 842-848... 

Alcaraz, A., Hulsey, S.S., Haas, J.S., Riley, M.O., and Andresen, B.D., (September 1994) The Development of Solid Phase Extraction Methods for CW On-Site Sample Preparation In Support of the Cooperative On-Site Analysis Exercise (COSAX) Project , Report UCRL-ID-119316. 

Osman B, Ozer ET, Besirli N, Gucer S. Development and application of a solid phase extraction method for the determination of phthalates in artificial saliva using new synthesized microspheres. Polym test 2013 32 810-818. 

A method which uses supercritical fluid/solid phase extraction/supercritical fluid chromatography (SE/SPE/SEC) has been developed for the analysis of trace constituents in complex matrices (67). By using this technique, extraction and clean-up are accomplished in one step using unmodified SC CO2. This step is monitored by a photodiode-array detector which allows fractionation. Eigure 10.14 shows a schematic representation of the SE/SPE/SEC set-up. This system allowed selective retention of the sample matrices while eluting and depositing the analytes of interest in the cryogenic trap. Application to the analysis of pesticides from lipid sample matrices have been reported. In this case, the lipids were completely separated from the pesticides. 

Insufficient testing is one of the major causes of method failure. The amount of data needed to publish a new procedure in a peer-reviewed journal and the procedural detail supplied therein are often insufficient to allow a different user to validate a method rapidly. The developer should evaluate if the method will work using chemicals, reagents, solid-phase extraction columns, analytical columns, and equipment from various vendors. Separate lots of specific supplies within a vendor should be evaluated to determine if lot-to-lot variation significantly impacts method performance. Sufficient numbers of samples should be assayed to estimate the lifetime of the analytical column and to determine the effects of long-term use on the equipment. 

The method developer should identify critical points in the method. Frequently, the Youden test may be used to determine if temperature, time, flow rate for solid-phase extraction, weight, volume, and other variables in the method are critical. The developer needs to identify if it is acceptable to take a break during a procedure, length of the break, and steps that need to be completed quickly. Because of differences in background and training between analysts, method developers should not assume that other analysts will perform a technique in the same way as in the developer s laboratory. Often analysts will have different interpretations of simple terms such as shake , slow , complete , and fast . 

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