THE EFFECT OF COLLISION ENERGY, TARGET GAS AND TARGET GAS PURITY ON THE HIGH-ENERGY COLLISION-INDUCED PRODUCT ION SPECTRUM OF RENIN SUBSTRATE

The product ion spectrum of renin substrate has been studied in detail using a tandem double focusing mass spectrometer with an array detector. The effect of collision energy, in centre of mass coordinates, in relation to the behaviour of the a(n), (a(n) + 1) and d(n) ions has been delineated. Contamination of a helium target gas by only 3% of a heavier gas (air) will significantly alter the spectrum and as little as 10% will completely mask the helium spectrum. The behaviour of the a(n), (a(n) + 1) and d(n) ions at 2 keV collision energy (laboratory coordinates) as a function of the ratio of helium to air in the gas cell is shown for the first time.