L,2-Naphthoquinone-4-sulfonate

A iridine traces in aqueous solution can be determined by reaction with 4-(p-nitroben25l)pyridine [1083-48-3] and potassium carbonate [584-08-7]. Quantitative determination is carried out by photometric measurement of the absorption of the blue dye formed (367,368). Alkylating reagents interfere in the determination. A iridine traces in the air can be detected discontinuously by absorption in Folin s reagent (l,2-naphthoquinone-4-sulfonate) [2066-93-5] (369,370) with subsequent chloroform extraction and hplc analysis of the red dye formed (371,372). The detection limit is ca 0.1 ppm. Nitrogen-specific thermal ionisation detectors can be used for continuous monitoring of the ambient air. 

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. 

Dipping solution For aromatic amines Dissolve O.S g l,2-naphthoquinone-4-sulfonic add sodium salt in 30 ml water and add 65 ml ethanol and S ml acetic add [5]. 

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... 

Abou-Ouf et al. [16] described a spectrophotometric method for the determination of primaquine phosphate in pharmaceutical preparation. Two color reactions for the analysis of primaquine phosphate dosage form, which are based on 2,6-dichlor-oquinone chlorimide and l,2-naphthoquinone-4-sulfonate, were described. The reactions depend on the presence of active centers in the primaquine molecule. These are the hydrogen atoms at position 5 of the quinoline nucleus and the primary amino group of the side chain. The method was applied to tablets of primaquine phosphate and a combination of primaquine phosphate and amodiaquine hydrochloride. 

A spectrophotometric method for determination of primary and secondary amines requires development for each particular compound, determining the kinetics of reaction of the amine with sodium l,2-naphthoquinone-4-sulfonate (143) and the UVV absorption spectrum of the product, under a set of fixed conditions. The procedure was applied to determination of ephedrine (30) and amphetamine (28) in pharmaceutical samples339. Reagent 143 in a FLA. system was used for the fast determination of lysine (144) in commercial feed samples by multivariate calibration techniques, without need of chromatographic separation340. 

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... 

Folin A 0.02% sodium l,2-naphthoquinone-4-sulfonate in 5% sodium carbonate is sprayed on the plate, which is then dried to yield a variety of colors. 

Sodium 0 -Naphthoquinone-4 -sulfonate. 3,4-Di-hydro 3,4 dioxo-l-naphthalenesulfonic acid sodium salt sodium l,2-naphthoquinone 4 sulfonate 1,2-naphthoquinone-4-sulfonic acid sodium salt d-naphthoquinone-4-sul-tonic acid sodium salt. C,flH5NaOjS mol wt 260.20. C 46.16%, H 1,94%, Na 8.84%, O 30.74%, S 12.32%. Prepn Folin, J. Biol. Chem. 51, 377 (1922). 

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