L,2-Naphthoquinone-4-sulfonic acid

Dissolve 100 mg l,2-naphthoquinone-4-sulfonic acid sodium salt in 40 ml ethanol and add 20 ml perchloric acid (70%), 18 ml water and 2 ml formaldehyde solution in that order. 

For aliphatic amines Dissolve 0.6 g l,2-naphthoquinone-4-sulfonic acid sodium salt in 12 ml water, make up to 200 ml with ethanol (90%) and add 10 ml pyridine [8]. 

In the case of diuretics the chromatogram is Erst sprayed with sodium hydroxide solution (c = 1 mol/L) and then with a saturated solution of l,2-naphthoquinone-4-sulfonic acid sodium salt in ethanol — water (50-1-50) [11]. Stable orange-colored chromatogram zones appear over a period of ca. 15 min, their intensity increases on storage in the dark (1-2 days) [11]. 

Substances l,2-Naphthoquinone-4-sulfonic acid sodium salt... 

Salama and Omar have described a rapid, specific, and convenient colorimetric method for the determination of procaine hydrochloride in pharmaceutical preparations [40]. The method is based on an intensity measurement of the orange-red color developed when the drug is allowed to react with l,2-naphthoquinone-4-sulfonic acid (sodium salt) in an aqueous solution. The method is suited for routine analysis of official preparations of procaine. 

Cetin and Atmaca [41] reported HPLC analysis of vigabatrin in tablets by precolumn derivatization with l,2-naphthoquinone-4-sulfonic acid sodium salt and detected at 451 nm. Separation was achieved on a Shim-Pack CLS-ODS (5 /im) column (25 cm x 4 mm) with a mixture of 10 mM phosphoric acid-acetonitrile (75 25) as a mobile phase (flow rate... 

Cetin and Atmaca [42] also reported HPLC analysis of vigabatrin in human plasma and urine after precolumn derivatization with l,2-naphthoquinone-4-sulfonic acid sodium salt using UV-VIS detection... 

Fig. 17. The reaction mechanism of ampicillin sodium and l,2-naphthoquinone-4-sulfonic acid [53].

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). 

In order to prevent precipitation of metallic palladium, the following oxidizing agents are used Cu(II), Fe(III), benzoquinone, and l,2-naphthoquinone-4-sulfonic acid. Utilization of these compounds is necessary because oxygen does not oxidize Pd(0) to Pd(II). However, this oxidation takes place if the above-mentioned oxidation agents used have their reduced forms oxidized by air or oxygen ... 

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