title: Nonenzymic spectrophotometric determination of potential poison ivy cross-reactors.
abstract: I describe an inexpensive, nonenzymic analytical system for prescreening substances that might cross-react as Rhus toxing (e.g., poison ivy, poison oak, and sumac allergens) on human skin. By spectrophotometric assay after incubation with an oxidizing mixture of Cu(II)ammine complex and ammonium persulfate, I could accurately and reproducibly determine o-quinoidal products of several potential synthetic cross-reactors and native poison ivy allergen, and could distinguish these from catecholamines, resorcinol, p-hydroquinone, and a closely related phenol. A good correlation was obtained between this nonenzymic technique and an enzymic assay. This Cu(II)ammine/persulfate oxidative assay, however, is inexpensive and obviates any spectral interference from enzymic proteins.
mesh_terms: D000485:Allergens / Q000032:analysis*; D002395:Catecholamines / Q000032:analysis; D002396:Catechols / Q000276:immunology*; D003300:Copper; D003429:Cross Reactions; D006873:Hydroquinones / Q000032:analysis; D010947:Plants, Toxic; D000644:Quaternary Ammonium Compounds; D012118:Resorcinols / Q000032:analysis; D013053:Spectrophotometry; D013431:Sulfates; D012251:Toxicodendron / Q000276:immunology*
chemical_list: D000485:Allergens; D002395:Catecholamines; D002396:Catechols; D006873:Hydroquinones; D000644:Quaternary Ammonium Compounds; D012118:Resorcinols; D013431:Sulfates; C013901:cupric ammine; D003300:Copper