Alternative matrices

In the author s laboratory, it has never been found necessary to resort to matrices other than glycerol or 1-thioglycerol for the analysis of saccharides and glycoconjugates. Nevertheless, alternative matrices are often equally effective, and, in some laboratories, they are preferred. The most widely used include tetraethyleneglycol (4) and its higher-molecular-weight relatives, the poly(ethyleneglycol)s, and such basic matrices as N,N -bis(2-aminoethyl)ethylenediamine ( triethylenetetramine, 5), 2,2 -... 

Biosamples, taken from living people (mainly blood and urine) and from corpses during autopsy (blood, urine, vitreous humor, bile, and almost any tissue and organ), are analyzed for substances that are toxicologically relevant. Alternative matrices like hair and saliva are also considered for determination of illicit chugs. 

Copolymers, Composite Gels, and Other Alternative Matrices... 

Technically, testing of hair for drugs is no more difficult or challenging than testing in many other "alternative" matrices (for example, liver, bone, etc.). In fact, the application of analytical methods and instrumental approaches are in most cases quite similar, regardless of the initial matrix. At present, hair analysis is routinely used as a tool for detection of drug use in forensic science, traffic medicine, occupational medicine, and clinical toxicology. 

In this review, plant material and numerous biological fluids, mainly blood plasma and serum, urine, and saliva, as well as some alternative matrices such as bile, amniotic fluid, cord blood, meconium, and maternal hair among others will be... 

As previously mentioned, besides conventional matrices such as urine and blood, alternative matrices have become of great interest in toxicology. Different reviews describe the analysis of dmgs of abuse in saliva, sweat, and hair [53-56]. For conventional matrices, LLE and SPE are usually the methods of choice. However, for hair analysis, a more drastic extraction step is necessary initially, followed by a purification step [57]. 

Cone EJ Drug testing with alternative matrices II. Mechanisms of cocaine and codeine deposition in hair. J Anal Toxicol 1999 23 396-408. 

Compared to other drugs of abuse, analysis of cannabinoids presents some difficult challenges. THC and 11-OH-THC are highly lipophilic and present in low concentrations in body fluids. Complex specimen matrices, i.e., blood, sweat, and hair, may require multi-step extractions to separate cannabinoids from endogenous lipids and proteins. Care must be taken to avoid low recoveries of cannabinoids due to their high affinity to glass and plastic containers, and to collection devices for alternate matrices (Blanc et al. 1993 Bloom 1982 Christophersen 1986 Joern 1992). THC and THCCOOH are predominantly found in the plasma fraction of blood, where 95% to 99% are bound to lipoproteins. Only about 10% of either... 

Kintz P and Samyn N (2000) Unconventional samples and alternative matrices. In Bogusz MJ (ed.) Handbook of Analytical Separations - Forensic Science, 1st edn., pp. 459—488. Amsterdam Elsevier Science. 

Ganster J, Pinnow M, Fink H-P (2006) High tenacity man-made cellulose fibre reinforced thermoplastics - injection moulding compounds with polypropylene and alternative matrices. Compos A 37 1796-1804... 

For the period-two, two-component poly d(A-C)-poly d(G-T) we have two alternating matrices. 

For the LF, algorithm the modification to the four-component case follows in exactly the same manner. For poly d(A-C)-poly d(T-G), there are two alternating matrices in the s s given by (B.l) and a single a related to U by (B.3). 

Palomo, A. Palacios, M. (2003).Alkali-activated cementitious materials Alternative matrices for the immobilisation of hazardous wastes Part II. Stabilisation of chromium and lead, Cem Concr Res, 33, 289-295. 

The capability to analyze compounds and alternative matrices that are not stable under vacuum conditions. 

Wille SM, del Mar Ramirez-Femandez M, Samyn N, De Boeck G. Conventional and alternative matrices for driving under the influence of cannabis recent progress and remaining challenges. Bioanalysis 2010 2(4) 791—806. 

Other polymers were also studied as alternative matrices for SPEs, aU of them including ethylene oxide as basic unit, like for instance polyethylenoxide-methylethermethacrylate (PEOMA) and polyethylenglycol-alkylacrylate. However, no important improvements have been reported, and conductivity similar to that one observed in case of PEO-LiX complexes was typically observed [4, 73]. 

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