api 5000API 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). Source: AlaskaThe API 5000™ LCMSMS System is one of the most sensitive triple quadrupole mass spectrometers for complex bioanalytical samples.