Aromatic amines derivatizing

Pyrenecarboxaldehyde (101) was used for derivatization of primary aromatic amines to the corresponding Schiff bases, for their determination by HPLC-FLD LOD 1-2 pmol272. 

Fig. 9.8 presents another, more complex type of phosphate prodrugs, namely (phosphoryloxy)methyl carbonates and carbamates (9-26, X = O or NH, resp.) [84], Here, the [(phosphoryloxy)methyl]carbonyl carrier appears quite versatile and of potential interest to prepare prodrugs of alcohols, phenols, and amines. The cascade of reactions leading from prodrug to drug as shown in Fig. 9.8 involves three steps, namely ester hydrolysis, release of formaldehyde, and a final step of carbonate hydrolysis (X = O) or A-decar-boxylation (X = NH). Three model compounds, a secondary alcohol, a primary aliphatic amine, and a primary aromatic amine, were derivatized with the carrier moiety and examined for their rates of breakdown [84], The alcohol, indan-2-ol, yielded a carrier-linked derivative that proved relatively... 

Brede, C., Skjevrak, I. and Herikstad, H. (2003). Determination of primary aromatic amines in water food simulant using solid-phase analytical derivatization followed by gas chromatography coupled with mass spectrometry, J. Chrom. A, 983, 35-42. 

Whenever only primary amines need to be derivatized, fluorescamine often constitutes the reagent of choice. Fluorescamine, although nonfluorescent itself, can react with primary amines forming highly fluorescent pyrrolinones (139-144). Aliphatic primary amines favor derivatization reaction at pH 8-9, whereas primary aromatic amines exhibit optimal reactivity at pH 3-4. Secondary amines are also fully reactive with fluorescamine but their products do not fluoresce. However, secondary amines can be detected with fluorescamine if they are converted to primary amines by oxidation with N-chlorosuccinimide prior to their fluorescamine derivatization (145, 146). Alcohols can also interact with fluorescamine but this reaction is reversible as a result, alcohols just slow down the reaction rate of fluorescamine with primary amines. On the other hand, tertiary amines and guanidines are not reactive at all with fluorescamine. 

JF Lawrence, FE Lancaster. Determination of total non-sulphonated aromatic amines in food colour amaranth by dithionite reduction followed by derivatization and high performance liquid chromatography. Food Addit Contam 6(4) 415 -423, 1989. 

Methods for the analysis of aromatic amines in synthetic azo dyes and in food and beverages colored with these dyes have been developed. High-performance LC or GC methods are generally employed, often with the help of derivatization reaction and fluorimetric detection, with HPLC generally regarded as the best technique for the determination of aromatic amines. 

Analytical Properties (i-Cyclodextrin (cycloheptamylose) normal phase separation of positional isomers of substituted benzoic acids reverse phase separation of dansyl and napthyl amino acids, several aromatic drugs, steroids, alkaloids, metallocenes, binapthyl crown ethers, aromatics acids, aromatic amines, and aromatic sulfoxides this substrate has seven glucose units and has a relative molecular mass of 1135 the inside cavity has a diameter of 0.78 nm, and the substrate has a water solubility of 1.85 g/ml, although this can be increased by derivatization Reference 13-28... 

Molecules which are not electrochemically active can be derivatized using an appropriate "electrophore", making the derivative eligible for electrochemical detection (9). It is fortunate that the nitrophenyl group, commonly used for UV and GC derivatization, is easily reducible. Methods based on the determination of intact carbamate residues by GC have been very disappointing as the result of thermal instability of a large majority of carbamate compounds. Therefore, a number of derivatization methods have been proposed. Carbamates, which produce an aromatic amine or phenol when hydrolyzed, were derivatized using 2,4-Dinitrofluorobenzene (DNFB) to form 2,4-... 

Dove [74] analysed a complicated mixtuie of aromatic amines after their conversion into TFA derivatives on a mixed stationary phase containing 9.5% of Apiezon L and 3.6% of Carbowax 20M (Fig. 5.5). The derivatization was performed in a 25-ml vial in which the sample of a mixture of amines (0.2 g) and a standard (0.05 g of n-dodecane) were dissolved in 2 ml of tetrahydrofuran and 5 drops of pyridine. The mixture was cooled in an ice-bath and 2 ml of TFA anhydride were added carefully. The contents of the vial were then heated at 50°C for 10 min, cooled and 5 ml of water were added. The mixture was extracted with 8 and 4 ml of dichloromethane. The extract was washed with 5 ml of saturated aqueous NaHC03 and 5 ml of water, dried over anhydrous Na2S04 and a 5-pi portion was chromatographed. 

Cinchonidine displays a tertiary amine, an aromatic amine and a free hydroxyl functionality. Direct hydrosilylation with unprotected cinchonidine (derivatized with a double bond for hydrosilylation), led to a cross-linked product. Thus, hydrosilylation was performed on PHMS with the trimethylsilyl derivative 1 (Fig. 10), in the presence of (EtjS)jPtClj as catalyst (0.05%), for 6h at 80°C in toluene. The hydroxyl group was deprotected with methanol at 65°C during 120 h. Size Exclusion Chromatography showed that the polysiloxane backbone was not degraded. A maximal grafting percent of 15% could be obtained, relative to the SiH units. 

Iodide in urine [39] and catecholamines [40,41] are example of analytes recently detected electrochemically and studied under IPC conditions. Pulsed amperometric detection on a gold electrode was used to detect etimicin [42] and gentamicin [43] in commercial samples, thus avoiding tedious pre-column derivatization. Heterocyclic aromatic amines in soup cubes [44] were determined by a coulometric electrode array detector, and the coulometric detection of a quinone-bearing drug candidate [45] allowed the study of electrochemical properties. 

The transfer of ions as pairs from one phase to a second is important in pre-analy tical extractive strategies. Ion-pair extraction of amines with bis-2-ethylhexylphosphate and derivatization with isobutyl chloroformate prior to GC-MS analysis was expedient for the simultaneous determination of aliphatic and aromatic amines in ambient air and airborne particulate matters [25]. The determination of 5-aminoimidazole-... 

Aromatic amines undergo condensation with fluorescamine (93), presumably according to equation 7, to yield fluorescent products (94). The process was applied to derivatize PAA mixtures prior to determination by MEKC with FLD (Section IV.C)189,190. This derivatizing procedure was used for detection of unreacted isocyanate residues in the... 

This sample preparation method involves steam distillation of the volatile organic components of a sample followed by preconcentration by LEE using a water-insoluble solvent. SDE served as unique clean-up and preconcentration step before derivatization, in the GC-MS determination of polycyclic aromatic hydrocarbons, phenols and aromatic amines in particulate phase mainstream cigarette smoke . Preconcentration by the SDE... 

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