Have a look at this ones:

http://mzmine.sourceforge.net/

https://xcmsonline.scripps.edu/

http://www.bioconductor.org/packages/release/bioc/html/xcms.html

but remember, there is no  "identification" with single MS

http://link.springer.com/article/10.1007%2Fs11306-012-0434-4

Generally speaking, a LC/MS using a single MS cannot provide identification information, but it is not all that bad. It depends how "clean" is your LC/MS spectra, and if you have some hypothesis what the molecule could be (target compound analysis). If the mixture is very complex and poorly LC separated, you will not go very far. If it is a simple mixture, with an a priori single LC peak. You may approximate the molecular mass information from the m/z ion including its first decimal. The more abundant ion  could not be the molecular derived ion by proton addition or subtraction, but could  arise from a cluster ion, a proton bound dimer, etc... thus a careful check of all the major peaks is necessary. If you think of a possible molecular formula from a priori knowledge, check if the isotopic pattern agrees with the expected formula. Do not forget to include chromatographic retention parameters.

A positive identification is rarely obtained, but it can validate, or more certainly invalidate an expected formula. That is probably the best that you may obtain with your instrument.

Hi,

you can also use the following database: METLIN (at Scripps Metabolomics Centre, http://metlin.scripps.edu/index.php), which let you to search by m/z; Lipidmaps (http://www.lipidmaps.org/data/structure/LMSDSearch.php?Mode=SetupTextOntologySearch) where you can search by either m or formula; CheBI (http://www.ebi.ac.uk/chebi/); KEGG (http://www.genome.jp/kegg/compound/). Currently, METLIN gives links to other databases for any compound.

However, as previously said by others LC-MS data are not enough for a full identification. You will also need MS/MS data at least.

Hope this be useful. Regards

hi, the important thing is that which ionization source and operating mode that is positive or negetive mode u r using in ur MS instrment.. and if DAD is present it will help u alot in recognizing the class of compound by matching reported values of maximum absorbance and shape of the DAD spectrum and the . if ionizaion source is  ESI the peaks u gonna get in ur spectrum will appear with adducts,, and the most common encountered adducts u can check out  at the site mentioned in the previous answer  and tz one http://www.alchemistmatt.com/mwtwin.html 

LC-MS will surely help u to appraoch to the most approximate structure..