Waters 2996 - Page 12

xii Table of Contents
3.2 Replacing the Lamp ........................................................................................ 25
3.3 Replacing the Fuses......................................................................................... 27
Chapter 4
Principles of the 2996 PDA Detector Optics
.............................................. 29
4.1 2996 Detector Optics....................................................................................... 29
4.2 Resolving Spectral Data.................................................................................. 31
4.3 Measuring Light at the Photodiode................................................................. 32
4.4 Computing Absorbance Data Points ............................................................... 35
4.4.1 Calculating Absorbance..................................................................... 35
4.4.2 Resolution ......................................................................................... 38
4.4.3 Filtering Data .................................................................................... 38
Chapter 5
Spectral Contrast Theory
.............................................................................. 41
5.1 Comparing Absorbance Spectra...................................................................... 41
5.2 Representing Spectra as Vectors ..................................................................... 42
5.2.1 Vectors Derived from Two Wavelengths .......................................... 43
5.2.2 Vectors Derived from Multiple Wavelengths ................................... 43
5.3 Spectral Contrast Angles................................................................................. 44
5.4 Undesirable Effects ......................................................................................... 47
5.4.1 Detector Noise ................................................................................... 47
5.4.2 Photometric Error ............................................................................. 48
5.4.3 Solvent Changes ............................................................................... 48
5.4.4 Threshold Angle ............................................................................... 48