Extractive derivatization

C. L. Hsu and R. R. Walters, Assay of the enantiomers of ibutilide and artilide using solid-phase extraction, derivatization and achhal-cliiral column-switcliing high-performance liquid cliromatography , J. Chromatogr. B 667 115-128 (1995). 

For most of the methods mentioned above the method uncertainty - important for the expression of material homogeneity, better inhomogeneity - is influenced by different analytical steps such as digestion, and/or extraction, derivatization, separation etc., that are often required to achieve the final result. This consequently increases the method uncertainty. 

Munch DJ, Munch JW, Pawlecki AM (1995) EPA Method 552.2. Determination of haloacetic acids and dalapon in drinking water by liquid-liquid extraction, derivatization and gas chromatography with electron capture detection. U.S. EPA, Cincinnati, OH, Available at http //www.caslab.com/EPA-Methods/PDF/552 2.pdf... 

Oximes, hydroxamic acids and related species are often used as reagents in inorganic analytical chemistry for precipitation, gravimetric and volumetric determinations as well as for preconcentration, extraction, derivatizations and subsequent determination of analyte using instrumental techniques. A brief review of analytical chemistry in general and of these species in particular follows. 

Avoidance of errors in sample preparation (extraction, derivatization) could be minimized by rigorous training of laboratory personnel, including appreciation of the patient behind each anonymous test tube. An environment free of noise and distractions is required to minimize the risk of serial solvent extractions being pooled in the wrong tube redundant labeling of glassware and step-by-step checklists are also critical elements of error prevention and detection. 

Analytes can be separated from complex matrices by sample preparation techniques that include liquid extraction, supercritical fluid extraction, and solid-phase extraction. Dilute ionic analytes can be preconcentrated by adsorption onto an ion-exchange resin. Nonionic analytes can be concentrated by solid-phase extraction. Derivatization transforms the analyte into a more easily detected or separated form. 

Spectroscopic techniques have received increased attention for the study of natural organic matter (NOM) over the past decades (Hatcher et al., 2001 Abbt-Braun et al., 2004). Such techniques allow the determination of molecular speciation in many cases without the need for extractions, derivatization, or hydrolysis. Spectroscopy is generally less selective in nature than for example chemical extraction techniques, even of chemically or thermally recalcitrant compounds (Frimmel et al., 2002 Haberstroh et al., 2006), though important restrictions for specific bonds apply for some spectroscopic techniques. Equally important are the potentials to investigate the spatial relationships between NOM and mineral phases, surface properties and alteration, and micro-scale heterogeneity within NOM. With improved capabilities and access to synchrotron facilities, worldwide efforts in applying an entire range of powerful spectroscopic tools have proliferated in all areas of science. 

Metals Extraction, derivatization, concentration, speciation UV-VIS molecular absorption spectrophotometry, ion chromatography... 

D. Chambers, Extractive derivatization of primary amines and beta-aminoalcohols with aromatic aldehydes to form Schiff base or oxa-zolidine products for analysis by electron capture gas chromatography, Diss. Abstr. Int. b. 44(7) 2148, (1984). 

Fig. 16 Variable internal standard responses due to multiple sample processing steps (liquid-liquid extraction, derivatization, and solid-phase extraction). Analyte gestodene internal standard norethindrone...

Steroids in matrix Hydrolyzing conjugates Extraction Derivatization Internal standard MS mode Reference... 

Extract, clean extract, derivatized with pentafluoro-benzyl bromide... 

The content of aroma compounds is, in general, low, and compositions of these compounds are often complex. Therefore, at the dawn of analytical chemistry, aroma compounds were extracted from a huge mass of raw material. Fractionation was carried out by means of distillation, and various other classical procedures (e.g., crystallization, pH control in extraction, derivatization) were employed. Quite obviously, compounds revealed using these procedures were inevitably restricted to a set of major constituents, if any. Occasionally, before the 1950s, additional techniques like UV-IR spectroscopy and open-column chromatography were employed and were helpful to some extent. 

The authors of this book provide an update of the methodology used in flavor research. Many improvements in instrumental sensitivities and capabilities have accrued in recent years, and state-of-the-art instrumentation and instrumental techniques for flavor analyses compose a substantial portion of this volume. New methods for extracting, derivatizing, and otherwise manipulating flavor compounds are another important part of this book, as are the chapters that deal with sensory evaluation. As editors, we are grateful to the authors for their contributions and to our respective employers for their support of our effort. 

The aim of this review is to present the different methodologies reported for cannabis detection in human hair (sample, decontamination, hydrolysis, internal standards [IS], extraction, derivatization, system of detection) and the analytical performances observed. 

Summary of Pretreatment of Hair Samples, Extraction, Derivatization, and Ranges of Concentration for Amphetamines in Hair... 

Sample comparison involves analysis of a number of the different types of products found in cocaine, usually carried out after an extraction, derivatization and GC-MS protocol. 

Matthews, D. R., Shults, W. D., Guerin, M. R. Extraction-derivatization gas-chromatographic determination of trace phosphate in aqueous media. AnaL Chem. 43, 1582 (1971)... 

EXTRACTION/DERIVATIZATION COLUMN/MOBILE PHASE APPROXIMATE RETN TIME DETECTION SENSITIVITY REF... 

Schwertner et al. introduced a salting-out procedure, in combination with single extraction using chloroform-isopropanol (95 5). 100 pi plasma samples could be effectively extracted with 2 ml chloroform-isopropanol. Theophylline was derivatized with pentafluoroben-zyl chloride, and 3-isobutyl-l-methylxanthine was used as an internal standard. This standard is similar to theophylline in extractability, derivatization rates, stability and chromatographic properties. Accurate measurements of plasma concentrations ( + 0.22 ug/ml) could be obtained with little or no interference from theophylline metabolites and other coextract-able material. A packed column with 3 OV-17 on Gas Chrom Q and temperature programming from 150°C to 250°C was used in combination with an electron capture detector. 

Complex environmental monitoring measurements are generally based on successive analytical steps, such as extraction, derivatization, separation and detection. This succession multiplies the risk that the traceability chain is broken because of a lack of appropriate references (e.g. pure calibrants, reference materials). Reference methods usually refer to methods with high metrological qualities (they may actually be standardized methods), and examples are provided by primary methods that are directly traceable to SI units without the need to use an external calibration. 

Extract with methylene chloride discard extract derivatize aqueous fraction with p-chlorobenzaldehyde extract with methylene chloride dry and dissolve in ethyl acetate. 

F.A.J. van der Hoorn, F. Boomsma, A.J. Man in t Veld and M.A.D.H. Schalekamp, Improved measurement of urinary catecholamines by liquid liquid extraction, derivatization and high-performance liquid chromatography with fluorometric detection, J. Chromatogr. 563 348-355 (1991). 

NaOH extraction, derivatization with NaBEt4, CGC separation and QFAAS detection... 

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