Analytical Chemistry

Figure 4.34
(a) Optical path in a UV photodiode array detector. (b and c)
Three-dimensional display from UV diode array detector;
azathioprine and impurities separated by reversed-phase (RP)
HPLC with HP 1040A detector coupled to an HP 85 microcomputer:
(b) isometric projection of data showing components 1–5;
(c) reversed projection of data showing components 1–3, 5
and 6. Key: (1) 1-methyl- 4 - nitro- 5 - hydroxyimidazole;
(2) 1-methyl- 4 - nitro- 5 - thioimidazole; (3) 6-mercaptopurine;
(4) 1-methyl- 4 - nitro- 5 - chloroimidazole; (5) azathioprine;
(6) process impurity.