Sanchez R I, Darsley M J, Martin M T
IGEN, Incorporated, Rockville, Maryland 20852.
Anal Biochem. 1995 Jan 1;224(1):190-4. doi: 10.1006/abio.1995.1028.
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.
本文描述了一种用于定量银染电泳凝胶条带和X射线胶片图像中银含量的新型分光光度法。通过以下步骤对切除区域中的银进行定量：（i）用硝酸将Ag0氧化/溶解为Ag+；（ii）中和后用双硫腙（二苯基硫代卡巴腙）的有机溶液萃取；（iii）在600nm处进行可见吸光度测量。由于双硫腙与Ag+结合时会发生从蓝绿色到黄色的显著颜色变化（Δε600 = 3.28×10⁴ M⁻¹ cm⁻¹），所以可以进行分光光度法定量。对银染凝胶以及通过化学发光和放射自显影获得的X射线胶片图像进行的实验表明，颜色变化与存在的银量有关，因此与条带或图像所代表的物质的量有关。该方法是使用密度计定量含银图像的一种方便、廉价的替代方法。
