O-Phthal aldehyde

Note o-Phthaldehyde in the presence of mercaptoethanol or cysteine has already been discussed as a reagent [4]. The present monograph describes the use of o-phthal-aldehyde in the presence of sulfuric add. There are, in addition, a number of applications, which have been described, employing o-phthalaldehyde without any additives e. g. for the detection of primary arylamines, histamine, histidine and histidylpeptides [5-71. 

When one is deciding what column geometry is optimal for trace analysis with unlimited sample volume, two additional points should be evaluated. First, to what extent does the analysis require accurate and reproducible injections Strict performance specifications may eliminate microbore columns from consideration. The accuracy and reproducibility of injection systems that deliver 0.1-, 0.2-, and 0.5-/xL samples have not been adequately characterized. Second, if the analyte of interest requires postcolumn derivatization, construction of a postcolumn reaction system that is compatible with the exceedingly small band volumes characteristic of microbore columns may be extremely difficult, but not impossible. Apffel et al. (28) developed and evaluated both packed-bed and open tubular postcolumn reactors for use with 1-mm i.d. analytical columns. Catecholamines were postcolumn derivatized with o-phthal-aldehyde and detected spectrofluorometrically. The 5-/zm particle... 

Cyclopolymerization of dialdehydes was extensively studied by Aso and his coworkers (50). It was remarkable that o-phthalaldehyde could be polymerized readily (5Z-53), because aromatic aldehydes such as benzaldehyde, isophthalaldehyde and terephthalaldehyde did not polymerize with common ionic catalysts. In addition, the poly[o-phthal-aldehyde] obtained was composed of only cyclic structural units. These results suggested that the driving force for the polymerization of o-phthalaldehyde was apparently attributable to the formation of the five-membered ring in the course of cyclopolymerization. The ceiling temperature of the polymerization of o-phthalaldehyde was calculated to be — 43° C from the relationship between the equilibrium concentration of the monomer and the polymerization temperature (51,52). 

Detector F ex 340 em 455 following post-column reaction with derivatization reagent pumped at 0.9 mL/min. (Derivatization reagent was commercially available (Pierce) or prepared by adding 2.5 mL 2-mercaptoethanol and 2.5 mL Brij-35 to 850 mg o-phthal-aldehyde in 10 mL MeOH, mix until decolorization is complete, add 1 L buffer, filter (0.45 xm), and refrigerate until used. Buffer was prepared by adjusting pH of 250 mM boric acid to 9.5 with 5 M KOH.)... 

Gentamycin is a widely used antibiotic but presents a number of undesirable side-effects when administered in high doses. Thus, it is vital to be able to monitor serum levels accurately. In the past this has been achieved using a number of assay methods other than HPLC. However, recently an HPLC method which compares favourably with microbiological assay methods has been described (Marples and Oates, 1982). This system utilises pre-column derivatisation with o-phthal-aldehyde to facilitate fluorimetric detection with subsequent resolution on a Spherisorb 5-ODS reversed phase support using isocratic conditions with methanol-water-EDTA (Fig. 11.9.4). Baseline resolution of tobramycin and four gentamycin components was achieved by this method. 

Other highly sensitive reagents are 2,4,6-trinitro-benzosulfonic acid, l,2-naphthoquinone-4-sulfonic acid (Folin s reagent), and 4,4 -tetramethyldiaminodi-phenylmethane (TDM). Intensely fluorescing amino acid derivatives are formed by reaction with o-phthal-aldehyde in the presence of reducing agents with pyr-idoxal and zinc ions and with dansyl chloride (5-di-methylaminonaphthalene sulfonyl chloride). 

The compounds detected by the method could, therefore, better be described as o-phthal-aldehyde reactive substances (ORS) expressed as glycine equivalents. The automated techniques presented below are based on the procedures described by Josefsson et al. (1977) and Delmas et al. (1990) with modifications. Manual determinations are possible as well provided a fluorimeter for static measurements is available. 

Phosphoryl chloride) see Phosphorus oxychloride o-Phthal aldehyde Phthalic acid anhydride... 

Aliphatic amines 4-Chloro-7-nitrobenzo-l,2,5-oxadiazole o-Phthal-di aldehyde 72... 

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