title: Spectrophotometric quantitation of silver in X-ray film images and silver-stained electrophoresis gel bands.
abstract: This paper describes a novel spectrophotometric method for quantitating the silver in silver-stained electrophoresis gel bands and X-ray film images. Silver in excised areas is quantitated by (i) oxidation/solubilization of Ag0 to Ag+ with nitric acid, (ii) neutralization followed by extraction into an organic solution of dithizone (diphenylthiocarbazone), and (iii) visible absorbance measurement at 600 nm. Spectrophotometric quantitation is possible because dithizone undergoes a dramatic color change from blue-green to yellow upon binding Ag+ (delta epsilon 600 = 3.28 x 10(4) M-1 cm-1). Experiments with silver-stained gels and with X-ray film images obtained by chemiluminescence and autoradiography demonstrated that the color change relates to the amount of silver present and hence to the amount of material represented by the band or image. This method is a convenient, inexpensive alternative to the use of a densitometer to quantitate silver-containing images.
authors.affiliation: IGEN, Incorporated, Rockville, Maryland 20852.
authors.forename: R I
authors.initials: RI
authors.lastname: Sanchez
authors.forename: M J
authors.initials: MJ
authors.lastname: Darsley
authors.forename: M T
authors.initials: MT
authors.lastname: Martin
mesh_terms: D004591:Electrophoresis, Polyacrylamide Gel; D012834:Silver / Q000032:analysis*; D016622:Silver Staining; D013053:Spectrophotometry; D014962:X-Ray Film
chemical_list: D012834:Silver