Derivatization reactions for

G. Lunn and L. Hellwig, Handbook of Derivatization Reactions for HPLC, John Wiley Sons, Ltd, Chichester (1999). 

Figure 7 (A) Luminol-type CL reagents and (B) derivatization reactions for DPH and...

Bulky substituents confer stability on organogermanium compounds. Scheme 1 shows possible derivatization reactions for some substitued germanes and digermanes. Compounds d and e are obtained from reactions a and b3 as mixtures of diasteroisomers, however, reactions a3, b4 and b3 are more stereospecific. Compounds b-i in the scheme were characterized by H NMR spectra118. 

SCHEME 1. Derivatization reactions for germanes and digermanes stabilized by bulky substituent... 

This compound was essentially non-toxic to house flies by topical application but showed moderate activity against the green rice leafhopper and brown planthopper as a residual spray. These results raise the possibility of applying derivatization reactions for the synthesis of polymeric insecticidal materials which may act as slow release agents. 

In this chapter, recent work is presented on derivatization reactions for TLC and HPLC. Detection methods for TLC which are based on colorimetric spray reactions have been excluded. However, some TLC methods which may be applied to HPLC analysis have been included. 

The carboxyl group reacts relatively easily even with mild silylating agents, so silyla-tion is often used as a derivatization reaction for carboxylic acids. The advantage of these derivatives applies particularly to substituted acids, which are almost always involved when the analysis of biochemically important acids is concerned. The usually necessary two-step preparation of the derivatives may be obviated the disadvantages are the sensitivity of the derivatives towards moisture and sometimes their low stability. 

The formation of hydrazinohydrazones [similar to compounds (I) have been reported for the reaction of unsaturated carbonyl compounds with dialkyl hydrazines. Hence, the existence of different products means that the quantitative yield of each of them is not enough, as is necessary for GC analysis of derivatives. It is quite probable that the same anomalies can take place in the reactions of unsaturated carbonyls with other reagents. For example, unsaturated 2,4-DNPHs seem unstable at the high temperatures of injectors and GC columns. This fact explains the small number of published RI data for the derivatives of these compounds and the necessity to search the new types of derivatization reactions for them. 

Anders and Mannering introduced on-column derivatization of morphine with propionic anhydride and obtained only one peak. They believed that it was dipropionylmorphine. Von Meyer et al. made use of the same derivatization reaction for the quantitative determination of morphine in blood, but they found that the monopropionyl derivatives of morphine and nalorphine (used as an internal standard) were found in the proportion 99 1, as compared with the... 

Derivatization reactions, often selective for amine type (primary, secondary, tertiary), have also been used to improve the detection and separation of these amines. Examples of derivatization reaction for GC determination of amines are shown in Table 11.5. 

Acylation is one of the most popular derivatization reactions for primary and secondary amines (Figure 11.1). The reagents listed in Table 11.5 easily react with amino groups under mild reaction conditions. In the reactions of amines with acid anhydrides and acyl chlorides, it is usually necessary to remove excess reagent and byproduct acid because these compounds damage the GC column. 

Examples of derivatization reaction for HPLC determination of amines are shown in Table 11.6. 

Kataoka, H., Derivatization reactions for the determination of amines hy gas chromatography and their apphcations in environmental analysis, J. Chromatogr., 133, 19-34, 1996. 

Derivatization of A-nitrosamines can be employed not only to convert nonvolatile nitrosamines into volatile materials suitable for GC analysis, but also to improve selectivity and sensitivity, and to reduce the analysis time. The commonly used derivatization reactions for GC analysis of nitrosamines are stated below. 

Derivatization Reactions for High Performance Liquid Chromatographic Determination of N-Nitrosamines with Fluorescence Detection... 

GC analysis of LAS is only possible after derivatization into volatile derivatives. Desulfonation of LAS in the presence of strong acids like phosphoric acid leads to linear alkylbenzenes (LAB). The identification of every single LAB isomer by GC-FID is achieved with detection limits lower than 1 /rg/1. In an alternative derivatization method, LAS are converted into their alkylbenzene sulfonyl chlorides by PCI5, which can be directly analyzed by GC-FID. Derivatization reactions for aliphatic anionic surfactants have mainly been described for product analysis. Among the very few methods for environmental analysis, the derivatization of alkyl sulfates to their corresponding trimethylsilylesters followed by determination with GC-FID is mentioned here. ... 

L. Nondek, Band Broadening in Solid-Phase Derivatization Reactions for Irreversible First-Order Reactions. Anal. Chem., 56 (1984) 1192. 

Adamsite 1 is the most difficult of the organoarsenicals to analyze. It has very high thermal stability and does not hydrolyze readily in the environment. Like most arsenicals, attempts to assess Adamsite by gas chromatography (GC) lead to rapid column deterioration and Adamsite carmot be derivatized with thiol derivatives <2003JCH(1000)253>. Schoene etal. developed two derivatization reactions for Adamsite. In the first, it was reacted with bromine in AcOH to give 2,2, 4,4, 6,6 -hexabromodiphenylamine 37. The alternative derivatization involved pyrolytic ethylation with dimethylformamide diethyl acetal (DMFDEA) and pyridine to yield 10-ethyl-5,10-dihydrophenarsazinine 38. The reaction mixture, which is Adamsite, EtOH, pyridine, and DMFDEA 39, was stored for 3 days in a closed vial at 90 °C. On column injection of 1 pi from this solution, no ethyl derivative could be detected, whereas splitless injection at 290°C injector temperature afforded EtPA 38 in the expected amount (Scheme 14) <1996JCH(719)401>. 

Falick and Maltby have also evaluated benzylation as a potential derivatization reaction for FAB MS of peptides. The benzyl esters show a moderate improvement in sensitivity over methyl esters (about fourfold for Thr-Lys-Pro-Arg). Since the benzyl moiety is a strong chromatophore, one can also obtain a substantial increase in HPLC sensitivity (at 215 nm) in addition to the improved FAB MS performance. 

Table 1 Some derivatization reactions for HPLC/UV detection...

Krull IS, Deyl Z, and Lingeman H (1994) General strategies and selection of derivatization reactions for EC. Journal of Chromatography B, Biomedical Applications 659. 

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