Dear Sir. Concerning your issue about the measurement of the molecular mass of an unknown sample using waters TQD LCMSMS. An LC/MS/MS is a liquid chromatograph (LC) system coupled with a quadrupole mass spectrometer (MS). MS quadrupole is the most common mass analyzer, which allows low scan time and is ideal for LC or GC inlets. When analyzing with LC/MS/MS, the LC separates compounds by conventional chromatography on a column. After the compounds enter the quadrupole mass detector, the solvent is removed and the compounds are ionized. Ions are filtered on the basis of their mass-to-charge ratio (m/z). Ions below and above a certain m/z value will be filtered out depending on the ratio of the direct current (DC) and alternating current (AC) voltages. By ramping the voltages on each set of poles, a complete range of masses can be passed to the detector. Liquid chromatography can separate metabolites that are not volatile and have not been derivatized. As a result, LC/MS can analyze a much wider range of chemical species than GC/MS. Samples commonly analyzed by LC/MS include amino acids (18 out of 20 amino acids can be derivatized, but the remaining two cannot) and sugars larger than trimers. The LC/MS/MS setup has higher compatibility detecting polar compounds such as organic acids, organic amines, nucleosides, ionic species, nucleotides, and polyamines compared to a GC/MS/MS. LC/MS is better suited for a discovery based approach when researching unknown metabolites, or when many of the targeted metabolites GC/MS incompatible due to volatility issues. I think the following below links may help you in your analysis:

https://www.waters.com/webassets/cms/library/docs/720004752en.pdf

http://www.ecs.umass.edu/eve/facilities/equipment/Quattropremier/EWRE%20easy%20guide%20LCMS.pdf

http://proj3.sinica.edu.tw/~core/metabolomics/doc/2017_Waters_cpmprehensive.pdf

Thanks

Salam Mahfuzur,

Inject your samples in full scan mode and see how many peaks come out.

Dear Sir,

You can use ESI positive and negative mode and scan in full range.

Kindly go through http://www.lipidmaps.org/.