3,5-Dinitrosalicylic acid

3,5-Dinitrosalicylic acid (DNS or DNSA, IUPAC name 2-hydroxy-3,5-dinitrobenzoic acid) is an aromatic compound that reacts with reducing sugars and other reducing molecules to form 3-amino-5-nitrosalicylic acid, which strongly absorbs light at 540 nm. It was first introduced as a method to detect reducing substances in urine by James B. Sumner^[2] and has since been widely used, for example, for quantifying carbohydrate levels in blood.^[3] It is mainly used in assay of alpha-amylase. However, enzymatic methods are usually preferred due to DNS's lack of specificity.^[4]

DNS method measurements.

3,5-Dinitrosalicylic acid^[1]

Names
Preferred IUPAC name 2-Hydroxy-3,5-dinitrobenzoic acid
Other names 3,5-Dinitrosalicylic acid
Identifiers
CAS Number	609-99-4 N
3D model (JSmol)	Interactive image
Beilstein Reference	2220661
ChEBI	CHEBI:53648 Y
ChEMBL	ChEMBL2260697
ChemSpider	11380 Y
ECHA InfoCard	100.009.278
EC Number	210-204-3
Gmelin Reference	5309
KEGG	C11319 Y
PubChem CID	11873
UNII	2ACT5NW8HU Y
CompTox Dashboard (EPA)	DTXSID9060576
InChI InChI=1S/C7H4N2O7/c10-6-4(7(11)12)1-3(8(13)14)2-5(6)9(15)16/h1-2,10H,(H,11,12) Y Key: LWFUFLREGJMOIZ-UHFFFAOYSA-N Y InChI=1/C7H4N2O7/c10-6-4(7(11)12)1-3(8(13)14)2-5(6)9(15)16/h1-2,10H,(H,11,12) Key: LWFUFLREGJMOIZ-UHFFFAOYAQ
SMILES c1c(cc(c(c1C(=O)O)O)[N+](=O)[O-])[N+](=O)[O-]
Properties
Chemical formula	C7H4N2O7
Molar mass	228.116 g·mol−1
Appearance	Yellow needles or plates
Melting point	182 °C (360 °F; 455 K)
Solubility in water	Soluble
Solubility in organic solvents	Soluble in ethanol, diethyl ether, benzene
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H302, H315, H318, H319, H335
Precautionary statements	P261, P264, P270, P271, P280, P301+P312, P302+P352, P304+P340, P305+P351+P338, P310, P312, P321, P330, P332+P313, P337+P313, P362, P403+P233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Synthesis

3,5-Dinitrosalicylic acid can be prepared by the nitration of salicylic acid.^[5]