Sodium-1,2-naphthoquinone-4-sulfonate

Glutathione does not react with 1,2-naphthoquinone-4-sodium sulfonate (30, 49). Cysteine (30) and cysteinylglycine (50), however, react to form a red color which is not destroyed by sodium hyposulfite. Many compounds form a colored condensation product with naphthoquinone sulfonate. However, these are all decolorized by sodium hyposulfite (30). Glutathione may be determined indirectly following hydrolysis. Glutamyl-cysteine (51), homocysteine (52), and isocysteine (52) do not react with the reagent. Thioglycolic acid (49) produces one fifteenth of the color produced by cysteine. The method is not specific for the reduced form and the results indicate the total of reduced plus oxidized compoimds. Approximately 0.1 mg. is required for analysis (49). 

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]. 

Spray solution For amino acids Dissolve 0.2-0.3 g l -naphthoquinone-4< sulfonic acid sodium salt in 100 ml aqueous sodium carbonate solution (5-10%) [1]. 

For aromatic amines Dissolve 0.5 g 1 -naphthoquinone-4 sulfonic acid sodium salt in 95 ml water and treat with 5 ml glacial acetic acid [1,6] if necessary, filter off the insoluble part [1],... 

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... 

Lillie RD, Pizzolato P, Dessauer HC, et al. Histochemical reactions at tissue arginine sites with alkaline solutions of /J-naphthoquinone-4-sodium sulfonate and other o-quinones and oxidized o-diphenols. J. Histochem. Cytochem. 1971 19 487 197. 

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... 

Naphthoquinone-4-sulfonic acid, sodium salt (0.5% in 1 Nacetic acid) Ninhydrin... 

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. 

White or gray needles, usually Contg 0.5 11.O May turn pink on exposure to light, especially when moist. Insol in water, alcohol, ether, benzene sol in hot sodium bisulfite soln sol in alkaline soln but such solns oxidize quickly on exposure to air yielding a brown substance which is sol in hot water giving a green soln. Controlled oxidation with HNOj yields ammonium 1,2-naphthoquinone-4-sulfonate, see Fieser, toe. eiz... 

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). 

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

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