Fast blue salt

Dipping solution Dissolve 140 mg fast blue salt B in 10 ml water and make up to 40 ml with methanol. Add 20 ml of this solution with stirring to a mixture of 55 ml methanol and 25 ml dichloromethane. 

Fast Blue Salt B Reagent 289 Spray solution II Caustic soda solution (c = 0.1 mol/1)... 

Fast blue salt B couples best with phenols in alkaline medium, e.g. with 11-nor-d -THC-9-carboxylic acid to yield the following red-colored product ... 

Note The detection is not affected if the dipping solution exhibits a slight opalescent turbidity. Fast blue salt BB [18] or fast blue salt RR [18,19] can be employed in the reagent in place of fast blue salt B. It is occasionally preferable not to apply spray solutions I and II separately but to work directly with a 0.1% solution of fast blue salt B in caustic soda solution (c=l—2mol/l) [13, 15] or in 0.5% methanolic caustic potash [3]. 

A dipping solution consisting of 0.2% fast blue salt B in hydrochloric acid (c = 0.5 mol/1, immersion time 30 s) has been reported for the detection of resorcinol homologues [1]. 

Fig. 1 Chromatograms of urine samples containing THC metabolites detection with fast blue salt RR (A) and fast blue salt B (B). Track Ai and B, metabolite-free urines tracks A,6 and B15 represent ca. 60 ng total cannabinoids per ml urine (determined by RIA).

Note The alternative fast blue salt BB produced the most intensely colored chromatogram zones for visual analysis in daylight, while fluorescence quenching in UV light (A = 254 nm) was greater with fast blue salt B and fast blue salt RR (Figs. 1 and 2). 

Fast blue salt B, fast blue salt BB, fast black salt K, diazotized sulfanilic acid (Pauly s reagent), diazotized sulfanilamide or 4-nitroaniline... 

Phenols (capable of coupling) Fast blue salt B, fast blue salt BB, fast black salt K, diazotized sulfanilic acid (Pauly s reagent) diazotized sulfanilamide or 4-nitroaniline Intensely colored azo dyes are formed. Catecholamines [20, 3S], imidazoles [21] and amines capable of coupling also react. [3, 17]... 

It is also probable that there is coupling to colored derivatives in the case of aromatic amines and phenols (cf. Fast blue salt B reagent). 

Dipping solution Dissolve O.S g fast blue salt BB (C.I. 3717S) in 2S ml water and make up to 100 ml with methanol [1]. 

Spray solution Dissolve 0.5 g fast blue salt BB in 100 ml water [2]. 

Fast blue salt BB couples with phenols, preferably in alkaline medium, to yield intensely colored azo dyes. 

The reagent solutions should always be freshly made up and fast blue salt B should always be stored in the refrigerator. 

Substances Fast blue salt B Methanol Dichloromethane... 

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