University of North Florida
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Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Email: schalk@unf.edu
Website: @unf

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Frank L. Neely

Abbrev:
Neely, F.L.
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Vistakon
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Citations 4

"Determination Of Monensin In Fermentation Broth By HPLC With Post-column Derivatization"
J. Liq. Chromatogr. Relat. Technol. 1992 Volume 15, Issue 9 Pages 1513-1522
Frank L. Neely

Abstract: Samples of fermentation broth were diluted tenfold with methanol and the suspension obtained was homogenized with a grinder and allowed to settle for 1 h at 5°C, followed by filtration of the supernatant, if necessary. For HPLC a Regis Little Champ column of ODS silica was used with a mobile phase (1.5 mL min-1) of aqueous NH4H2PO4 (adjusted to pH 3.0 with H3PO4) - methanol (3:17), post-column reaction at 120°C with 3% vanillin in methanolic 3% H2SO4 in a coil (10 ft x 0.01 in.) and detection at 520 nm. A rectilinear calibration graph was obtained for 0.25 to 2.0 mg mL-1 of monensin with a response ratio of 0.86 for A to B form. Recovery of added monensin was >97%, and the mean coefficient of variation of determination was 1.2%.
Monensin Fermentation broth HPLC Spectrophotometry Post-column derivatization Heated reaction

"Determination Of Sterigmatocystin In Fermentation Broths By Reversed-phase High Performance Liquid Chromatography Using Post-column Fluorescence Enhancement"
J. Chromatogr. A 1990 Volume 523, Issue 1 Pages 305-311
Frank L. Neely* and Curt S. Emerson

Abstract: Sterigmatocystin (I, fungal toxin often found in food) was separated from the broth by homogenization with methanol, filtration, extraction of I from the filter-cake with methanol and 0.45 µm re-filtration of the supernatant solution A portion of solution was subjected to HPLC in a column (25 cm x 4.6 mm) of Beckman Ultrasphere C18 (5 µm) with use of a guard column (1.5 cm x 3.2 mm) of Brownlee Newguard RP-18 (7 µm), a mobile phase (0.5 mL min-1) of aqueous 88% methanol, post-column derivatization (reaction coil diameter 0.01 in.) at 35°C with aqueous 5% AlCl3 (added at 0.5 mL min-1) and fluorimetric detection at 455 nm (excitation at 254 nm). The limit of detection was 0.09 ppm, with rectilinear calibration range from 0.1 to 15 ppm and coefficient of variation (n = 12) of 0.2% at 0.82 ppm. A TLC separation on Whatman LK-5D silica with a mobile phase of 1% acetic acid in CCl4 - CHCl3 (1:1) and fluorimetric detection of the same derivative is summarized.
Sterigmatocystin Fermentation broth HPLC Fluorescence Sample preparation Column Filtration Extraction C18 Post-column derivatization Detection limit Calibration Silica

"Rapid HPLC Determination Of Narasin In Fermentation Broth"
Chromatographia 1991 Volume 31, Issue 5-6 Pages 277-280
F. L. Neely

Abstract: A rapid HPLC assay with post-column derivatization with vanillin was developed for the determination of narasin (I) in fermentation broth. Separation was carried out on an ODS (3 µm) column (5 cm x 4.6 mm o.d.) with a mobile phase (2 mL min-1) of 93% methanol - 7% 0.1 M K2HPO4 (pH 4). The post-column reagents (viz, methanolic H2SO4 and vanillin) were mixed (1 mL min-1) at a tee fitting before mixing with the column eluate. Detection was at 520 nm. Response was rectilinear from 1 to 300 ppm of I. The coefficient of variation were 2% and recoveries were 101 to 120%. No matrix interference was observed.
Narasin Fermentation broth HPLC Interferences Post-column derivatization

"Flow Injection Determination Of Tylosin In Fermentation Broth"
Anal. Chim. Acta 1993 Volume 281, Issue 2 Pages 243-247
Frank L. Neely*

Abstract: Fermentation broth was extracted with isopropyl acetate. A portion (5 µL) of the solution was injected into the reagent stream (3 ml/min) of cis-aconitic anhydride in acetic anhydride/isopropyl acetate (1:1). The reaction took place at 45°C in a stainless-steel tube reactor and the absorbance of the red salt formed was measured at 525 nm. The calibration graph was linear for 0.11-2.2 mM tylosin (I). The linear range was extended to 11 mM I, by changing the wavelength to 560 nm. Recovery was 96.6-106.1% for fermentation broth spiked with a concentration. aqueous solution of I over the domain 50-500% of initial I concentration. The method may be applied in the determination of a variety of antibiotics possessing a tertiary amine moiety.
Tylosin Antibiotics Fermentation broth Spectrophotometry Sample preparation Extraction Reactor