Rapid Determination of Sulfur in Liquid Hydrocarbons for At-Line Process Applications Using Combustion/Oxidation and UV-Fluorescence Detection

Abstract A rapid and sensitive liquid chromatographic (LC) method was developed for the determination of am- picillin residues in raw bovine milk, processed skim milk, and pasteurized, homogenized whole milk with vitamin D. Milk samples were deprote- inized with trichloroacetic acid (TCA) and acetonitrile. After centrifugation, the clear supernatant was reacted with formaldehyde and TCA under heat. The major fluorescent derivative of ampicillin was then determined by reversed-phase LC with fluorescence detection. Average recoveries of ampicillin fortified at 5,10, and 20 ppb (ng/mL) were all >85% with coefficients of variation <10%. Limits of detection ranged from 0.31 to 0.51 ppb and limits of quantitation, from 0.66 to 1.2 ppb. After appropriate validation, this method should be suitable for rapid analysis of milk for ampicillin residues at the tolerance level of 10 ppb.

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Rapid Determination of Fluoroquinolone Residues in Honey by a Microbiological Screening Method and Liquid Chromatography

Journal of AOAC International ◽

10.1093/jaoac/93.4.1331 ◽

2010 ◽

Vol 93 (4) ◽

pp. 1331-1339 ◽

Cited By ~ 10

Author(s):

Maki Kanda ◽

Tomoto Kusano ◽

Setsuko Kanai ◽

Hiroshi Hayashi ◽

Yoko Matushima ◽

...

Keyword(s):

Bacillus Subtilis ◽

Liquid Chromatography ◽

Fluorescence Detection ◽

Efficient Method ◽

Rapid Determination ◽

Screening Method ◽

Microbiological Method ◽

Metal Free ◽

Spe Method

Abstract A rapid and efficient method was developed for the simultaneous determination of seven fluoroquinolone (FQ) residues: norfloxacin, ciprofloxacin, danofloxacin, enrofloxacin, orbifloxacin, sarafloxacin, and difloxacin in honey. The samples were first screened with a microbiological method by using test plates made from metal-free purified agar seeded with Bacillus subtilis BGA. When a sample was found to contain FQ residues by using the microbiological method, it was analyzed by LC with fluorescence detection (LC/FL). FQs were extracted with Na2EDTA-McIlvaine buffer and purified by a dual SPE method in which a cation-exchange cartridge was connected to an anion-exchange cartridge. The overall recoveries of the seven FQs ranged from 70.0 to 92.1. The intra-assay and interassay CVs were 7.8 and 5.1, respectively. For the microbiological method, the LOD values ranged from 2 to 9 g/kg. For LC/FL, the LOQ values ranged from 2 to 7 g/kg. The developed method was used to analyze 70 honey samples. In 14 samples in which the microbiological method detected the presence of FQ residues, norfloxacin, ciprofloxacin, and enrofloxacin were identified by LC/FL.

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Rapid Determination of Nosiheptide in Meat and Egg by Liquid Chromatography with Fluorescence Detection

Journal of AOAC International ◽

10.1093/jaoac/83.1.17 ◽

2000 ◽

Vol 83 (1) ◽

pp. 17-19 ◽

Cited By ~ 5

Author(s):

Shozo Horii ◽

Naoto Oku

Keyword(s):

Liquid Chromatography ◽

Phosphoric Acid ◽

Fluorescence Detection ◽

Mobile Phase ◽

Lower Layer ◽

Rapid Determination ◽

Chicken Muscle

Abstract A procedure was developed to determine nosiheptide residues in marketed meat and egg. Acetonitrile was used for the extraction, and the extract was partitioned with hexane to remove fat. The lower layer was reconstructed and quantitated by liquid chromatography using fluorescence detection at 357 nm excitation and 500 nm emission. The mobile phase consisted of 0.025% phosphoric acid–acetonitrile (50 + 50, v/v). Recoveries of nosiheptide from fortified samples ranged from 91.3 to 95.2% for swine muscle, 88.6 to 92.7% for chicken muscle, and 86.3 to 86.8% for egg. The method was used to monitor swine and chicken muscle and egg (20 samples each) in the market. Nosiheptide was not determined in all 60 samples.

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