Finally, the base was identified from the molecular weight difference between the extension product and extension primer by bio mass spectrometry (MALDI TOFMS or ESI QqTOFMS).

• 用基质辅助激光解吸电离 -飞行时间质谱 ( MALDI-TOFMS)或电喷雾电离 -四极杆飞行时间质谱 ( ESI-Qq TOFMS)检测延伸产物与未延伸引物间的分子量差异 ,确定该点处碱基。