Amino acids derivatised

K Ou, MR Wilkins, JX Yan, AA Gooley, Y Fung, D Sheumack, KL Williams. Improved high-performance liquid chromatography of amino acids derivatised with 9-fluorenylmethyl chloroformate. J Chromatogr A 723 219-225, 1996. 

As outlined in Scheme 4.4.1, starting from commercially available Fmoc-amino acid derivatised Wang resins 247, or those prepared by known loading procedures, deprotection with 20%... 

Used for fluorimetric detn. of amines and amino acids derivatising reagent for hplc analysis of primary and secondary amines. Cryst. (MeOH). Mp 93-95°. 

Reagent for protecting amino acids. Derivatisation reagent for gas chromatog. anal, of amines. Liq, Bpj2 77-81°. 

Reagents which form a derivative that strongly absorbs UV/visible radiation are called chromatags an example is the reagent ninhydrin, commonly used to obtain derivatives of amino acids which show absorption at about 570 nm. Derivatisation for fluorescence detectors is based on the reaction of non-fluorescent reagent molecules (fluorotags) with solutes to form fluorescent... 

Amino acid composition was analysed as described by Barkholt and Jensen (6). Cysteine was determined after derivatisation with 3,3 -dithiopropionic acid. Tryptophan was not determined. 

NMR can be a powerful tool for determination of enantiomeric excess or absolute configuration of the optically active compounds, however, these processes require the use of some auxiliaries, for example, chiral lanthanide shift reagents or chiral derivatising agent. In many cases, the starting point for determination of enantiopurity of amines, amino acids or diols is the formation of chiral imines. 

In determination of the enantiomeric purity of aliphatic primary amines, the use of (S-aminoalcohols and ot-amino acids 1R(—)-myrtenal as a derivatising agent has been tested.1... 

A GC analysis of amino acids requires a derivatisation step to increase the volatility of the amino acids. Generally, norleucine and/or norvaline are the internal standards added to the hydrolysate to check the derivatisation yield. According to the experimental method applied, the limits of detection (LOD) vary in the range 10 100 pg for each amino acid. Regarding the chromatographic columns, as most of the derivatives are esters barely polar compounds the most commonly used are fused-silica capillary columns with a low... 

Derivatising agent Determined amino acids Reference... 

Table 9.2 summarises the derivatisation methods most used for the analysis of amino acids in paint hydrolysate. In particular ... 

Chromatographic procedures applied to the identification of proteinaceous paint binders tend to be rather detailed consisting of multiple analytical steps ranging from solvent extractions, chromatography clean up, hydrolysis, derivatisation reactions, and measurement to data analysis. Knowledge of the error introduced at each step is necessary to minimise cumulative uncertainty. Reliable results are consequently obtained when laboratory and field blanks are carefully characterised. Additionally, due to the small amounts of analyte and the high sensitivity of the analysis, the instrument itself must be routinely calibrated with amino acid standards along with measurements of certified reference proteins. All of these factors must be taken into account because many times there is only one chance to take the measurement. 

Figure 14.7 Principal derivatisation strategies for the GC C IRMS of lipids [trimethylsiylation (cholesterol) and esterification (fatty acids)] and amino acids (esterification acylaction)...

GC-C-IRMS instrumentation enables the compound-specific isotope analysis of individual organic compounds, for example, n-alkanes, fatty acids, sterols and amino acids, extracted and purified from bulk organic materials. The principle caveat of compound-specific work is the requirement for chemical modification, or derivatisation, of compounds containing polar functional groups primarily to enhance their volatility prior to introduction to the GC-C-IRMS instrument. Figure 14.7 summarises the most commonly employed procedures for derivatisation of polar, nonvolatile compounds for compound-specific stable isotope analysis using GC-C-IRMS. 

Corr, L. T., Berstan, R. and Evershed, R. P. (2007b) Optimisation of derivatisation procedures for the determination of 813C values of amino acids using gas chromatography/combustion/isotope ratio mass spectrometry. Rapid Communications in Mass Spectrometry 21, 3759 3771. 

Mopper [265] has described developments in the reverse phase performance liquid chromatographic determination of amino acids in seawater. He describes the development of a simple, highly sensitive procedure based on the conversion of dissolved free amino acids to highly fluorescent, moderately hydrophobic isoindoles by a derivatisation reaction with excess o-phthalaldehyde and a thiol, directly in seawater. Reacted seawater samples were injected without further treatment into a reverse-phase high-performance liquid chromato-... 

X sometimes with organic divinylbenzene) surface derivatised elements, pharmaceuticals, amino acids,... 

Cohean S. (1984) A pre-column derivatisation method for amino acid analysis. Waters Lab highlights No. 220. Available as a downloadable file from the Waters website (http //www. waters.com). 

The presence of electron-withdrawing groups (notably the nitro group) sited in the ortho or para positions of an aryl halide facilitates the halogen replacement. Here the mechanism proceeds by an addition-elimination sequence and it is discussed and illustrated in the formation of 2,4-dinitroaniline and 2,4-dinitrophenylhydrazine (Section 6.8.2, p. 959), and in the use of 1-fluoro-2,4-dinitrobenzene in the derivatisation of an amino group in an amino acid (Section 9.6.23, p. 1279). 

Amino acids (isoleucine, phenylalanine, arginine and alanine) have been analysed on a microchip with a post-channel reaction with amino acid oxidase reaction [144], Pre-channel derivatisation of amino acids with naphthalene-2,3-dicarboxyaldehyde (NDA) has been described for facilitating its amperometric detection [145]. Separation and direct detection of amino acids without derivatisation have also been achieved in microchips [89,109,122,132,146-148]. 

Haberhauer-Troyer, C., G. Alvarez-Llamas, E. Zitting, et al. 2003. Comparison of different chlorofor-mates for the derivatisation of seleno amino acids for gas chromatographic analysis. J. Chromatogr. A 1015 1-10. 

The variety of sampling methods that are available, ie dilute and concentrated samples, suspensions, solids, surfaces and combination with chromatographic methods, such as that used in the high performance liquid chromatography separation of o-phthalyl dialdehyde derivatised amino acids in natural and sea water samples. 

Belokon et al. have published a somewhat intricate protocol for the N -methylation of a histidine isomer, itself an imidazolium derivatised a-amino acid [158] (see Chapter 6). The amino group can be N-boc protected and the resulting imidazolium salt reacted with silver(I) oxide to yield the corresponding silver(l) carbene complex. The functional groups in the wingtip group... 

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