戴安公司3-戴安HPLC液相色谱基础(PPT)精品.ppt

* * * The diagram show the generic layout of a photo diode array detector. All of the energy from a broad spectrum lamp (or lamps) usually covering both the ultarviolet and visible wavelength range is passed through a flow cell. The light is then split into its component wavelenghts on a grating. A series of diodes measures the light intensity over the entire wavelenght range. The result is two types of data, a traditional chromatogram (time vs absorbance) at any wavelentgh in the operating range, and a spectrum (wavelength vs absorbace) at any given time point. Data collected from a PDA detector is often refered to as 3 dimensional data. * Intensity vs Time at any given wavelength Intensity vs Wavelength at any given time point. * * Spectral resolution (or Bandwidth) is the wavelength interval (in nm) between data points in an acquired spectrum. The minimal resolution of the 2996 detector is 1.2 nm. As an example, in 3D mode, the 2996 averages 3 adjacent diodes for each reported wavelength when the spectral resolution is set to 3.6 nm. * Spectrum of Caffeine * * * * Mass Spectrums of Irgonox (MW 530), a polymer additive. * * * In API, a compound can acquire a positive or negative charge. Some compounds can acquire both, which is dependent on their functional groups and proton activity in its environment. This then requires that the hardware, the mass spectrometer, be capable of acquiring a chromatogram in the negative or positive mode or both in a single run. In this example we have acquired an SCAN chromatogram in the negative mode and positive mode. Prednisolone and Beta-Methazone only show in positive mode while Lansoprazole shows in both and Ibuprofen shows strongly in negative mode. * * * The areas of application of electrochemical detection are not large, but the compounds for which it does apply, represent some of the most important drug, pollutant and natural product classes. For these, the specificity, and sensitivity make it very useful for monit