41. The phytochrome pigment was identified using a spectrophotometer in 1959 by biophysicist Warren Butler and biochemist Harold Siegelman. 42. Not easy, but that's why we invented instruments, such as pH meters and spectrophotometers . 43. The science faculty boasts a Video Microscope, an Atomic Absorption, IR and 4 UV Visible Spectrophotometers . 44. Experimental variations such as the slit width ( effective bandwidth ) of the spectrophotometer will also alter the spectrum. 45. This can be observed with a standard UV / vis spectrophotometer , using a 10 cm path-length. 46. Friedkin recalls that an early model of the Beckman DU spectrophotometer was used by the penicillin researchers in Peoria. 47. Sherlock Holmes didn't know about DNA . He'd have gazed in bafflement at an infrared spectrophotometer . 48. For reflectance measurements, the spectrophotometer quantitatively compares the fraction of light that reflects from the reference and test samples. 49. In the UV, visible and near IR, absorbance and reflectance spectrophotometers usually illuminate the sample with monochromatic light. 50. As DCPIP is reduced and becomes colorless, the resultant increase in light transmittance can be measured using a spectrophotometer .
