api5000The API 5000™ LCMSMS System is 's most sensitive triple quadrupole mass spectrometer for small molecule analysis. Hhest sensitivity triple quadrupole mass spectrometer for small molecule analysis. Lowest limits ofAPI 5K API 5K means an API-defined BOP confuration with a rated working pressure of 5,000 psi and as described in API RP 53, adopted by reference at 20 AAC 25.527(c).