Interfaces, HPLC

Currently, HPLC/fiuorescence is still the most common technique for the determination of residues of oxime carbamates. With the introduction of ESI and APCI MS interfaces, HPLC/MS analysis for oxime carbamates in various sample matrices has become widespread. However, for a rapid, sensitive, and specific analysis of biological and environmental samples, HPLC/MS/MS is preferred to HPLC/MS and HPLC/fiuorescence. With time, improved and affordable triple-quadrupole mass spectrometers will be available in more analytical laboratories. With stricter regulatory requirements, e.g., highly specific and conclusive methods with lower LOQ, HPLC/MS/MS will be a method of choice for oxime carbamates and their metabolites. 

GC-GFAAS interfacing. HPLC-GFAAS has also been reported. 

Interfacing HPLC and electrospray has permitted remarkable advancements in biomedical analysis however, the process of successfully coupling these two techniques has required considerable efforts to overcome the limitations imposed by their distinctive operating requirements. 

Several interfaces had been developed, but at present, mainly electrospray ionization (ESI) and atmospheric pressnre chemical ionization (APCI) are widely used. In the ESI interface, HPLC... 

Interfacing HPLC or HPCE (capillary electrophoresis) to mass spectrometry is technically more complex than. with a GC because these techniques use a solvent that is often aqueous (water is a poison to mass spectrometers). The use of microcolumns in HPLC is desirable for coupling to MS because micro-columns operate at very low flow rates. They are also compatible with different ionisation techniques for the analysis of high molecular-weight species. 

Wu, J.C.G. 1991. Interfacing HPLC and cold-vapor AA with on-line preconcentration for mercury speciation. Spectrosc. Lett. 24 681-697. 

The interfacing HPLC with MS is problematic, as pointed out by the image proposed by Arpino of the coupling between HPLC-fish and MS-bird [72] one provides for the separation of neutral molecules in solution with high operating pressures, while the other responds to ions in the gas phase and requires high vacuum. The most widely used technique is electrospray ionization (ESI). It is suitable for analysis of highly polar compounds which are ionized in solution, such as... 

Falter, R., Wilken, R.D. Determination of carboplatinum and cisplatinum by interfacing HPLC with ICP MS using ultrasonic nebulisation. Sci. Total Environ. 225, 167-176 (1999)... 

Reverse-phase (RP)-HPLC is probably the best system for purifying triterpenoids, principally when mixtures of isomers are present [35]. Gunther and Wagner in 1996 [36] carried out the separation and quantification of active triterpenes from Centella asiatica employing an RP system with acetonitrile-water as mobile phase. Recently, Gaspar et al. [37] described the complete separation of a mixture of triterpenoid isomers from the fruit of Arbutus unedo by HPLC coupled to a mass spectrophotometer by means of a particle beam interface (HPLC-PBMS). The separation of different quassinoids from crude bark of Quassia amara was developed by Vitanyi et al. [38] using a reverse-phase HPLC-MS... 

The advantages of directly interfacing HPLC separation with NMR analyses have so far been limited by the time and amount of material required to obtain various NMR spectra. However, two different types of HPLC interface have been developed for LC-NMR analysis. In stopped-flow techniques, the material of interest is directed into an NMR sample cell within the magnetic field after HPLC separation has occurred, and the pumps are then stopped to allow the necessary NMR experiments to be performed. The second type of... 

The chromatographic methods most suitable for spectroscopic identification techniques are GC and HPLC although TLC and recently CZE and SFC methods have received attention. GC was the first technique to be interfaced to a mass spectrometer since it proved relatively easy to transfer the gaseous effluent and GC-MS instruments were capable of sufficiently rapid scan times even in the 1970s to acquire undiscriminated spectral data [1]. Interfacing HPLC systems proved more difficult due to... 

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