Comparison of the repeatability of quantitative data measured in high-performance liquid chromatography with UV and atmospheric pressure chemical ionization mass spectrometric detection

A detailed comparison of the repeatability of the retention times, the peak efficiencies and the peak areas of a dozen probe compounds achieved in HPLC, using either HPLC–UV or HPLC–MS for detection purpose, is reported. Three groups of conventional analytes, each one separated under a different set of experimental conditions, were selected for this study. Most of the compounds are basic, the other ones being neutral. The repeatabilities of the retention times do not exhibit any influence of the mode of detection. However, the repeatabilities of the peak areas and the column efficiencies are generally (although not always) better in HPLC–UV than that in HPLC–MS. On average, the precision for the UV peak area detection was 2.5% versus 6.8% for MS detection. Experimental results show that the response factor of the UV detector is more constant than that of the MS detector, probably because the HPLC flow-rate was sufficiently stable. The results obtained in the different tests are discussed.