1522_book.fm Page 193 Thursday, November 13, 2003 9:58 AM m/z minutes 110 12 106 11 100 10 91 90 9 80 8 77 70 7 65 6 60 MS spectrum of m-xylene. 5 51 50 4 40 © 2004 by CRC Press LLC 100% 75% 50% 25% kCounts 300 200 100 Figure 5.7