Simple spectrophotometer- the Jenway 6100 & Perkin Elmer Lambda 40. From that information, a calibration curve was plotted and used to. Home › Laboratory › Spectrophotometers › Jenway 6400 and 6405 Scanning Spectrophotometers Jenway 6400 and 6405 Scanning Spectrophotometers. Manual: Ordering Information. Supplied with pack 100 disposable cuvettes and mains lead (230V/50Hz) 640 501 - 6405 UV/visible, scanning spectrophotometer supplied with pack 100 disposable.
Note that it is always relative to a solution containing no dye.Transmittance is the relative percent of light passed through the sample.What makes all of this easy to use, however, is the conversion of that information from a percent transmittance to an inverse log function known as the Absorbance (or Optical Density).The Beer-Lambert LawDefiniton Absorbance: The negative log[pic][pic] of the transmittance. A = - log[pic][pic]T EQUATION G.1This value is more useful in spectrophotometry than transmittance, because of plot of absorbance vs concentration yields a straight line. A plot of transmittance vs concentration is an exponential. The - log calculates the inverse of transmittance, so that absorbance increases with increasing concentration. Transmittance would decrease as we increased the amount of red dye in our example. The relationship of Absorbance to concentration was shown by two biochemists to follow the equation for a straight line, y = mx +b, where m is the slope of the line and b is the y intercept. If the measurement is made in such a way that b = 0 (that is, a solution containing no dye has no absorbance), and if we substitute Absorbance for y, concentration for x, and variant for m, we arrive at the formulation of the Beer-Lambert Law: A = [pic] C where A = absorbance C = concentration [pic] = the extinction