The Quattro micro API mass spectrometer (Waters) consists of Z-Spray Atmospheric Pressure Ionization for electrospray ionization (ESI) and chemical ionization (APCI) sources and triple quadrupole mass analyzer. The system has a high performance tandem quadrupole analyzer with a mass range of 2-2000 amu in positive and negative detection modes. The system is very sensitive and suitable for qualitative and quantitative determinations of lipids, steroids, drugs and metabolites, nucleic acids, and peptides.