INTRODUCTION

　　The CMS-L is a high performance, easy to use, single quadrupole mass spectrometer with an extended mass range analysis capability to m/z 2000 – ideal for large molecule applications such as the analysis of proteins.Its small foot print makes it the instrument of choice for space restricted laboratories and is more affordable than comparable MS systems. The CMS-L brings the analytical benefits of mass spectrometry to more scientists than ever before.

　　A MS detector measures the mass to charge ratio (m/z) of an analyte ion, with electrospray ionization resulting in singly (or multiply) charged ions such as (M+H) + , called the molecular ion. Larger molecules such as peptides and proteins, can carry more than one charge, often carrying charges of 10-50 resulting in several ions in multiple charge states such as (M+19H) 19+ , (M+20H) 20+ , (M+21H) 21+ , etc. The resulting mass spectral pattern is commonly referred to as a ‘charge envelope’ with signals showing a characteristic spacing and intensity distribution. This MS data can be used to calculate the average mass of the analyte by using the approach shown below: