Oxygen liquid chromatography

P Dugo, L. Mondello, E. Sebastian , R. Ottana, G. Eirante and G. Dugo, Identification of minor oxygen heterocyclic compounds of citi us essential oils by liquid chromatography-atmospheric pressure chemical ionisation mass specti ometiy , J. Liq. Chromatogr. 22 2991-3005 (1999). 

One example of normal-phase liquid chromatography coupled to gas chromatography is the determination of alkylated, oxygenated and nitrated polycyclic aromatic compounds (PACs) in urban air particulate extracts (97). Since such extracts are very complex, LC-GC is the best possible separation technique. A quartz microfibre filter retains the particulate material and supercritical fluid extraction (SPE) with CO2 and a toluene modifier extracts the organic components from the dust particles. The final extract is then dissolved in -hexane and analysed by NPLC. The transfer at 100 p.1 min of different fractions to the GC system by an on-column interface enabled many PACs to be detected by an ion-trap detector. A flame ionization detector (PID) and a 350 p.1 loop interface was used to quantify the identified compounds. The experimental conditions employed are shown in Table 13.2. 

As a result of its unique chemical and physical properties, silica gel is probably the most important single substance involved in liquid chromatography today. Without silica gel, it is doubtful whether HPLC could have evolved at all. Silica gel is an amorphous, highly porous, partially hydrated form of silica which is a substance made from the two most abundant elements in the earth s crust, silicon and oxygen. Silica, from which silica gel is manufactured, occurs naturally, either in conjunction with metal oxides in the form of silicates, such as clay or shale, or as free silica in the form of quartz, cristobalite or tridymite crystals. Quartz is sometimes found clear and colorless, but more often in an opaque form, frequently colored... 

CALDWELL c R (2001) Oxygen radical absorbance capacity of the phenolic compounds in plant extracts fractionated by high-performance liquid chromatography, ,4Biochem, 293, 232-8. 

GUO c, CAO G, SOFIC E and PRIOR R L (1997) High-performance liquid Chromatography coupled with coulometric array detection of electroactive components in fruits and vegetables Relationship to oxygen radical absorbance capacity, J Agric Food Chem, 45, 1787-96. 

Because carotenoids are light- and oxygen-sensitive, a closed-loop hyphenated technique such as the on-line coupling of high performance liquid chromatography (HPLC) together with nuclear magnetic resonance (NMR) spectroscopy can be used for the artifact-free structural determination of the different isomers. 

Eligh performance liquid chromatography Density functional theory Oxygen reduction reaction Rotating disk electrode Rotating ring disk electrode... 

Photodiode detectors have already been cited in this chapter in relation to near-IR fluorescence measurements on singlet oxygen,(8 16 18) in decay-time temperature sensing,(50) in liquid chromatography,(62) the study of proteins labelled with Nile Red,(64) and diode laser spectrometry,(67) Photodiodes are also conveniently packaged for many applications in an array form enabling rapid data acquisition e.g., in spectrophotometry, (35)... 

Kurosawa S, Yoshimura T, Kurosawa H, Chiba K. 1995. Simultaneous determination of 18-oxygenated corticosteroids by high performance liquid chromatography with fluorescence detection. J Liq Chromatogr 18 2383-2396. 

Miyazawa T, Fujimoto K, Suzuki T, Yasuda K. Determination of phospholipid hydroperoxides using luminol chemiluminescence high-performance liquid chromatography. Oxygen Radicals in Biological Systems, Pt. C 233, 324-332, 1994. 

Schiff s reagent, liquid chromatography, 719 Sclerotium rolfsii, reactive oxygen species, 610 Scopoletin, hydrogen peroxide fluorometry, 627, 642... 

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