Derivatization fluorescence detection

Kim, M. Stewart, J.T. HPLC post-column ion-pair extraction of acidic drugs using a substituted a-phenylcinnamonitrile quaternary ammonium salt as a new fluorescent ion-pair reagent. J.Liq.Chromatogr., 1990, 13, 213-237 [derivatization fluorescence detection also benzoic acid, flu-fenamic acid, ibuprofen, ketoprofen, mefenamic acid, probenecid, salicylic acid, valproic acid]... 

R.L. Reuning, R.H. Digoxin disposition in elderly humans with hypochlorhydria. J.Clin.PharmacoL, 1994, 34, 734-741 [urine feces derivatization fluorescence detection normal phase digitoxin (IS) extracted metabolites LOD 5 ng/mL)... 

Roos, R.W. Lau-Cam, C.A. Liquid chromatographic analysis of conjugated and esterified estrogens in tablets. J.Pharm.Sci., 1985, 74, 201—204 [ethinyl estradiol is IS derivatization fluorescence detection]... 

Vinas, P., Balsalobre, N., Lopez-Erroz, C., and Hernandez-Cordoba, M., 2004b. Determination of vitamin Bg compounds in foods using liquid chromatography with post-column derivatization fluorescence detection. Chromatographia. 59 381-386. 

Ryan, P.J. Honeyman, T.W. Determination of fatty acids by higji-performance liquid chromatography of Dns-ethanolamine derivatives, J.Chromatogr., 1984, 312, 461-466. [derivatization fluorescence detection bulk linolenic acid palmitoleic acid linoleic acid eicosadienoic acid palmitic acid oleic acid elaidic acid margaric acid arachidonic acid]... 

You, J. Zhang, W. Jia, X. Zhang, Y. An improved derivatization method for sensitive determination of fatty acids by high-performance hquid chromatography using 9-(2-hydroxylethyl)-carbazole as derivatization reagent with fluorescence detection, Chromatographia, 2001, 54, 316-322. [derivatization fluorescence detection linoleic acid oleic acid stearic acid]... 

Halpin, R.A. Geer, L.A. Zhang, K.E. Marks, T.M. Dean, D.C. Jones, A.N. Melillo, D. Doss, G. Vyas, K.P. The absorption, distribution, metabolism and excretion of rofecoxib, a potent and selective cyclooxygenase-2 inhibitor, in rats and dogs, Drii Metafe.Dispos., 2000,1244-1254. [LOQ 1 ng/mL plasma post-column photochemical derivatization fluorescence detection]... 

Hsieh, J.Y.-K. Lin, L. Matuszewski, B.K. High-throughput liquid chromatographic determination of rofecoxib in human plasma using a fully automated on-line solid-phase extraction system, J.Liq.Chromatogr.Rel.TechnoL, 2001, 24, 799-812. [LOQ 0.5 ng/mL plasma post-column photochemical derivatization fluorescence detection SPE]... 

Niederberger, E. Tegeder, L Schafer, C. Seegel, M. Grosch, S. Geisslinger, G. Opposite effects of rofecoxib on nuclear factor-kappaB and activating protein-1 activation, J.Pharmacol.Exp.Ther., 2003, 304, 1153 1160. [plasma post-column photochemical derivatization fluorescence detection] Radhakrishna, T. Rao, D.S. Reddy, G.O. LC determination of rofecoxib in bulk and pharmaceutical formulations, J.Pharm.BiomedAncd., 2001, 26, 617-628. 

Post-column in-line photochemical derivatization permits fluorescence detection of the common aflatoxins Bl, B2, Gl, and G2 (60). Chromatographic evidence indicates that photolysis causes the hydration of the nonfluorescent Bl and Gl components to B2a and G2a components, respectively. Analysis of naturally contaminated com samples show no interfering peaks and permits the deterrnination of 1 and 0.25 ppb for Bl and B2, respectively. 

After the dipped or sprayed chromatogram has been dried in a stream of cold air long-wave UV light (2 = 365 nm) reveals fluorescent yellow zones (flavonoids). Sterigmatocystine, which can be detected without derivatization on account of its red intrinsic fluorescence (detection limit 0.5 pg), also fluoresces pale yellow after being heated to 80°C [9] or 100°C [13] for 10 min on the other hand, citrinine, zearalenone and vomitoxin fluoresce blue. 

EC, electrochemical detection Flu, fluorescence detection MS, mass specu-omeu-ic detection pre-Flu, fluorescence detection after pre-column derivatization post-Flu, fluorescence detection after post-column derivatization UV, UV absorbance detection. 

The mixture of free amino acids is reacted with OPA (Fig. 7-8) and a thiol compound. When an achiral thiol compound is used, a racemic isoindole derivative results. These derivatives from different amino acids can be used to enhance the sensitivity of fluorescence detection. Figure 7-9 shows the separation of 15 amino acids after derivatization with OPA and mercaptothiol the racemic amino acids may be separated on a reversed-phase column. If the thiol compound is unichiral, the amino acid enantiomers may be separated as the resultant diastereomeric isoindole compound in the same system. Figure 7-10 shows the separation of the same set of amino acids after derivatization with the unichiral thiol compound Wisobutyryl-L-cysteine (IBLC). 

We inferred that these properties might be exploited in a series of unique derivatizing reagents designed specifically for trace analysis of organic compounds using HPLC separation and fluorescence detection. The use of these pyridones for the analytical purposes reported here is based on their acidic properties. Treatment of a lH-2-pyridone with a base converts the pyridone to its salt. 

The increased use of IV-methyl carbamate insecticides in agriculture demands the development of selective and sensitive analytical procedures to determine trace level residues of these compounds in crops and other food products. HPLC is the technique most widely used to circumvent heat sensitivity of these pesticides. However, HPLC with UV detection lacks the selectivity and sensitivity needed for their analysis. In the late 1970s and early 1980s, HPLC using post-column hydrolysis and derivatization was developed and refined with fluorescence detection to overcome these problems. The technique relies on the post-column hydrolysis of the carbamate moiety to methylamine with subsequent derivatization to a fluorescent isoindole product. This technique is currently the most widely used HPLC method for the determination of carbamates in water" and in fruits and vegetables." " ... 

A variety of formats and options for different types of applications are possible in CE, such as micellar electrokinetic chromatography (MEKC), isotachophoresis (ITP), and capillary gel electrophoresis (CGE). The main applications for CE concern biochemical applications, but CE can also be useful in pesticide methods. The main problem with CE for residue analysis of small molecules has been the low sensitivity of detection in the narrow capillary used in the separation. With the development of extended detection pathlengths and special optics, absorbance detection can give reasonably low detection limits in clean samples. However, complex samples can be very difficult to analyze using capillary electrophoresis/ultraviolet detection (CE/UV). CE with laser-induced fluorescence detection can provide an extraordinarily low LOQ, but the analytes must be fluorescent with excitation peaks at common laser wavelengths for this approach to work. Derivatization of the analytes with appropriate fluorescent labels may be possible, as is done in biochemical applications, but pesticide analysis has not been such an important application to utilize such an approach. 

Reversed-phase HPLC followed by post-column derivatization and subsequent fluorescence detection is the most common technique for quantitative determination of oxime carbamate insecticides in biological and environmental samples. However, for fast, sensitive, and specific analysis of biological and environmental samples, detection by MS and MS/MS is preferred over fluorescence detection. Thus, descriptions and recommendations for establishing and optimizing HPLC fluorescence, HPLC/ MS, and HPLC/MS/MS analyses are discussed first. This is followed by specific rationales for methods and descriptions of the recommended residue methods that are applicable to most oxime carbamates in plant, animal tissue, soil, and water matrices. 

Mallat, E. and Barcelo, D., Analysis and degradation study of glyphosate and of aminomethylphosphonic in natural waters by means of polymeric and ion-exchange solid-phase extraction columns followed by ion chromatography-post-column derivatization with fluorescence detection, /. Chromatogr A, 823, 129, 1998. 

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