HPLC Equipment : Detectors Analytical Chemistry Lab, Department of Chemistry, Yonsei University

Characteristics of Ideal Detector Have high sensitivity and the same predictable response Response to all solutes or else have predictable specificity Have a wide range of linearity Be unaffected by changes in temperature and mobile phase flow rate Response independently of the M.P.

Ideal Detector Cont’d Not contributed to extra column band broadening Be reliable and easy to use Have linear response to solute Be non-destructive Provide qualitative and quantitative information Have a fast response

Characteristics of UV-VIS Capable of Very high Sensitivity (must UV-VIS absorption) Good linear range (~ 5 order) Very small cell volume (low band broadening) Relative insensitive to M.P. and temperature change (except very high sens) Very reliable and easy to use

UV-VIS cont’d 가장 흔하게 사용되는 검출기죠 Wide varying response for different solute Gradient elution capability Wave length can be selected Non-destructive to sample 가장 흔하게 사용되는 검출기죠

Characteristics of RI detector Excellent versatility – universal Moderate sensitivity (not for trace analysis) Efficient heat exchanger required Relatively insensitive to flow change Sensitive to type of M.P. and temp change Reliable, fairly easy to use Non-destructive Difficult to use with gradient elution

Flourescence detector High sensitivity Small sample size Selectivity but not versatility

LC-MS For most compounds, a mass spectrometer is more sensitive and far more specific than all other LC detectors. It can analyze compounds that lack a suitable chromophore. It can also identify components in unresolved chromato-graphic peaks, reducing the need for perfect chromatography.

Ion Source Electrospray ionization (ESI) Atmospheric pressure chemical ionization (APCI) Atmospheric pressure photoionization (APPI)

Difficulties on LC-MS The gas loaded to the vacuum system resulting from evaporating the M.P. is generally too high The M.P. composition often imcamparable with M.S. The transfer of polar and ionic analytes from the liquid to the gas phase is difficult

MC-MS operational 주의 사항