Photodiode array HPLC

Koves EM, Wells J. Evaluation of a photodiode array/HPLC-based system for the detection and quantitation of basic drugs in postmortem blood. J Forensic Sci 1992 37(l) 42-60. 

Remcho, V. T. McNair, H. M. Rasmussen, H. T. HPLC Method Development with the Photodiode Array Detector, /. Chem. Educ. 1992, 69, A117-A119. 

A mixture of methyl paraben, ethyl paraben, propyl paraben, diethyl phthalate, and butyl paraben is separated by HPLC. This experiment emphasizes the development of a mobile-phase composition capable of separating the mixture. A photodiode array detector demonstrates the coelution of the two compounds. 

Hplc techniques are used to routinely separate and quantify less volatile compounds. The hplc columns used to affect this separation are selected based on the constituents of interest. They are typically reverse phase or anion exchange in nature. The constituents routinely assayed in this type of analysis are those high in molecular weight or low in volatility. Specific compounds of interest include wood sugars, vanillin, and tannin complexes. The most common types of hplc detectors employed in the analysis of distilled spirits are the refractive index detector and the ultraviolet detector. Additionally, the recent introduction of the photodiode array detector is making a significant impact in the analysis of distilled spirits. 

Watmough, N.J.. Turnbull, D.M., Sherratt. H.S.A. Bartlett. K. (1989). Measurement of the acyl-CoA intermediates of p-oxidation by hplc with on-line radiochemical and photodiode-array detection. Application to the study of [U- C]hexadecanoate by intact rat liver mitochondria. Biochem. J. 262,261-269. 

BAILY R G, MCDOWELL L and NURSTEN H E (1990) Use of an HPLC photodiode array detector in a study of the nature of black tea liquor , J Sci Food Agric, 52, 509-25. 

Hong, V. and Wrolstad, R.E., Use of HPLC separation/photodiode array detection for characterization of anthocyanins, J. Agric. Food Chem., 38, 708, 1990. Osmianski, J. and Lee, C.Y., Isolation and HPLC determination of phenolic compounds in red grapes. Am. J. Enol. Vitic., 41, 204, 1990. 

Muller, H., Determination of the carotenoid content in selected vegetables and fruit by HPLC and photodiode array detection, Z. Lebensm. Enters. Forsch. A, 204, 88, 1997. 

D2O = deutered water. HPLC = high performance liquid chromatography. IS = internal standard. MeOH = methanol. MS = mass spectrometry. NMR = nuclear magnetic resonance. PDA = photodiode array detector. TEA = triethylamine. MTBE = methyl tert-butyl ether. 

The availability of HPLC systems coupled to photodiode array detectors allows for online spectral characterization of anthocyanins. 

Hong, V. and Wrolstad, R.E., Use of HPLC separation/photodiode array detection for characterization of anthocyanins, J. Agric. Food Chem., 38, 708, 1990. 

Chirinos, R. et al., High-performance liquid chromatography with photodiode array detection (HPLC-DAD)/HPLC-mass spectrometry (MS) profiling of anthocyanins from Andean mashua tubers (Tropaeolum tuberosum Ruiz and Pavon) and their contribution to the overall antioxidant activity, J. Agric. Food Chem., 54, 7089, 2006. 

NOTE HPLC detection of test drugs at 200 nm UV. Peak are named for the drugs they represent. Peak identity was discerned by analyzing each dmg individually and observing its retention time and UV spectrum by photodiode array detection between 190 and 360 nm using a Waters Model 990 PDA detector. Retention times are listed in the text. 

HPLC and LC/MS. HPLC methodology coupled with ultraviolet (UV), fluorescence (FL), photodiode-array (PDA) and/or a mass spectrometry (MS) detection has been developed. In general, neonicotinoids can be determined by HPLC/UV. Typical HPLC operating conditions are given in Table 2. 

Balogh, M.P and Li, J.B., HPLC Analysis of hypericin with photodiode-array and MS detection the advantages of multispectral techniques, LC-GC, 17(6), 558, 1999. 

A Waters 2690 Alliance HPLC equipped with a 996 photodiode array and a 896 IJV/Vis detector was used for carotenoid analysis. The column (Phenomenex, Torrance, CA) was a 250x4.6mm Ultracarb 3 pm C-18 stationary phase and elution was carried out isocratically at a flowrate of l.OmL/min with 85 15 (v v) acetonitrileimethanol (HPLC grade) containing 0.1% triethyl amine to prevent on-column carotenoid decomposition. 

A study has been carried out on the determination of triazine and carbamate pesticides and metabolities in seawater by HPLC with photodiode-array detection [393]. 

HPLC is a universal separation technique that is capable of separating both volatiles and non-volatiles without the need for derivatization. We are developing methods that employ both on-line photodiode array (PDA) detection and mass selective detection, HPLC/PDA/MS. This approach also utilizes an ion-trap mass... 

Figure 3.5 Three-dimensional display of the photodiode array absorbance data obtained by HPLC/PDA/MS for a M. truncatula extract. The first dimension is HPLC retention time, second is wavelength, and third is absorbance. The data can be rapidly previewed for specific absorbance regions characteristic of functional groups.

Multiple mass analyzers exist that can perform tandem mass spectrometry. Some use a tandem-in-space configuration, such as the triple quadrupole mass analyzers illustrated (Fig.3.9). Others use a tandem-in-time configuration and include instruments such as ion-traps (ITMS) and Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS or FTMS). A triple quadrupole mass spectrometer can only perform the tandem process once for an isolated precursor ion (e.g., MS/MS), but trapping or tandem-in-time instruments can perform repetitive tandem mass spectrometry (MS ), thus adding n 1 degrees of structural characterization and elucidation. When an ion-trap is combined with HPLC and photodiode array detection, the net result is a profiling tool that is a powerful tool for both metabolite profiling and metabolite identification. 

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