Fluorescence spectrometry light scattering

Although UV detection is most commonly used in the quahty control of drug substances, other detectors such as fluorescence, electrochemical, near infrared, refractive index, evaporative light scattering, or mass spectrometry may be used as appropriate. 

When a transparent medium was irradiated with an intense source of monochromatic light, and llie scattered radiation was examined spectroscopically, not only is light of the exciting frequency, v, observed (Rayleigh scattering), blit also some weaker bands of shifted frequency are detected. Moreover, while most of the shifted bands are of lower frequency, v - Aii, there are some at higher frequency, v + Aiq, By analogy to fluorescence spectrometry (see below), the former are called Stokes bands and the latter a iti-Stakes bands. The Stokes and anti-Stokes... 

Particle diameter Inductively coupled plasma-optical emission spectrometry (ICP-OES) Fourier transform infrared spectrometry Mass spectrometry X-ray fluorescence Extended X-ray absorption fine structure (EXAFS) spectroscopy X-ray absorption near edge (XANES) spectroscopy Static and dynamic laser light scattering Scanning probe technologies... 

Current IPC detectors are on-stream monitors. HPLC detectors range from (1) non selective or universal (bulk property detectors such as the refractive index (RI) detector), characterized by limited sensitivity, (2) selective (discriminating solute property detectors such as UV-Vis detectors) to (3) specific (specific solute property detectors such as fluorescence detectors). Traditional detection techniques are based on analyte architecture that gives rise to high absorbance, fluorescence, or electrochemical activity. Mass spectrometry (MS) and evaporative light scattering detectors (ELSDs), can be considered universal types in their own right... 

Liquid chromatography (LC) has already been described and is an excellent separation technique for compounds that are nonvolatile, thermally unstable and relatively polar in nature. The usual detectors for LC are based on refractive index, conductivity, amperometry, light scattering, UV and fluorescence, all of which have been discussed in Section 3.2. However, sometimes it is desirable to have a more powerful detector attached to an LC instrument and, as such, the following combinations are possible LC-infrared spectrometry, LC-atomic spectrometry, LC-inductively coupled plasma-mass spectrometry, LC-mass spectrometry, LC-UV-mass spectrometry, LC-nuclear magnetic resonance and even LC-nuclear magnetic resonance-mass spectrometry. 

Any of the methods of detection used in liquid chromatography can be used in IC, though some are more useful than others. If the eluent does not affect the detector the need for a suppressor disappears. Common means of detection in IC are ultraviolet (UV) absorption, including indirect absorption electrochemical, especially amperometric and pulsed amperometric and postcolumn derivatization. Detectors atomic absorption spectrometry, chemiluminescence, fluorescence, atomic spectroscopic, refractive index, electrochemical (besides conductivity) including amperometric, coulometric, potentiometric, polaro-graphic, pulsed amperometric, inductively coupled plasma emission spectrometry, ion-selective electrode, inductively coupled plasma mass spectrometry, bulk acoustic wave sensor, and evaporative light-scattering detection. 

Atomic emission detector (AED), electrochemical detection (ELCD), electron capture detection (ECD), evaporative light scattering detector (ELSD, including condensation nuclea-tion-CN), fluorescence detector (FLD, including laser-induced fluorescence), inductively coupled plasma-mass spectormetry (ICP-MS), mass spectrometry (MSD), MS/MS, MS(n), thermoionic detector (NPD), spectrometric detection (UV, Vis, DAD) ... 

In the introductory Section 2.1.3, it was discussed that an important aspect of optimization can be to improve a method for its applicability in trace analysis. The nature of the mode of detection is very relevant in this case whether the applied detector is concentration proportional like the very common UV detector or mass proportional hke nebulizer-based detectors, for example, evaporative light scattering detector (ELSD) or charged aerosol detector (CAD). This textbook contains dedicated chapters on nebulizer-based or aerosol detectors (Chapter 10 on trends in detection), as well as for the coupling of LC with mass spectrometry (Chapter 1). Here, the focus is on concentration proportional detectors UV detectors (VWD, DAD), fluorescence detectors (FLD), electrochemical detectors (ECD), and refractive index (RI) detectors. 

The main purpose of the detector in a field-flow fractionation (FFF) system is to quantitatively determine particle number, volume, or mass concentrations in the FFF size-sorted fractions. Consequently, a number, volume, or mass dependent size distribution of the sample can be derived from detection systems applied to FFF [e.g., (UV-Vis) fluorescence, refractive index, inductively coupled plasma ionization mass spectrometry (ICPMS)]. Further, on-line light scattering detectors can provide additional size and molecular weight distributions of the sample. 

DTPA = diethylenetriaminepentaacetic acid DL = detection limit EDTA = ethylenediaminetetraacetic acid ICP-MS = inductively coupled plasma mass spectrometry ISE = ion-selective electrode MCGE = membrane-coated graphite electrode NAP = 4-(/ -nitrophenylazo)-pyrocathecol PVC = poly(vinyl chloride RLS = resonance light scattering TBP = tri-n-butyl phosphate TOPO = tri- -octyl phosphine oxide XRF = X-ray fluorescence... 

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