JCAMP files are ASCII (text) files which essentially list compound name, molecular weight and other header information, plus the mass:abundance pairs which make up the mass spectrum, in a 'standard'* format. Currently, the Agilent (HP) ChemStation systems list JCAMP version 4.10.This is the simplest format into which library entries can be broken down. JCAMP files can be edited with a text editor, but you have to be really, really, really, careful, otherwise you will end up corrupting the entire file (i.e. you won't be able to convert it back to a useable library). Macros within the ChemStation software can convert JCAMP files to binary library files, and vice versa. More will be said about editing JCAMP files in the future. Meanwhile, a partial JCAMP file entry is shown below.
##TITLE=Library Entry 1 in D:\AAFS9912.XXX
##JCAMPDX=Revision 4.10 ##DATA TYPE=MASS SPECTRUM ##SAMPLE DESCRIPTION= ##NAMES= ##CAS NAME=YOHIMBINE ##MOLFORM=C21H26N2O3 ##CAS REGISTRY NO=000146-48-5 ##MP=-3.00000e+02 ##BP=-3.00000e+02 ##MW=354.194343 ##$RETENTION INDEX=0.00000e+00 ##$CONDENSED SPECTRUM=NO ##NPOINTS= 123 ##XYDATA=(XY..XY) 42 279 43 212 44 95 53 133 54 79 55 223 57 102 59 168 65 83 67 170 68 105 69 99 71 57 77 232 Etc. Etc.
*(The term "standard" is used loosely, since the HP JCAMP format does not comply to the generally accepted JCAMP-DX format).