scholarly journals Determination of Tetracycline Antibiotics in Salmon Muscle by Liquid Chromatography Using Post-Column Derivatization with Fluorescence Detection

2003 ◽  
Vol 86 (5) ◽  
pp. 925-929 ◽  
Author(s):  
Angelina L Pena ◽  
Celeste M Lino ◽  
M Irene N Silveira
Keyword(s):  
Fluorescence Detection ◽  
Solid Phase ◽  
Polymeric Sorbent ◽  
Tetracycline Antibiotics ◽  
Liquid Chromatographic Method ◽  
Limit Of Quantitation ◽  
Ethylenediaminetetracetic Acid ◽  
Cleanup Procedure ◽  
Liquid Chromatographic

Abstract A simple and accurate cleanup procedure using polymeric sorbent was developed for the determination of oxytetracycline (OTC) and tetracycline (TC) residues in salmon muscle. It was applied to the analysis of 20 salmon samples during a month period. The OTC and TC residues were extracted with ethylenediaminetetracetic acid (EDTA)–McIlvaine buffer acidified at pH 4.0 and cleaned up by solid-phase extraction with a polymeric sorbent. The advantages of the polymeric sorbent over the silica-based sorbent in the cleanup of salmon muscle samples are described. A liquid chromatographic method with post-column derivatization and fluorescence detection is proposed because of its sensitivity and specificity. The average recoveries of OTC and TC from muscle salmon tissue fortified at 50, 100, and 200 μg/kg levels, ranged from 83.9 to 93.4% with a coefficient of variation between 4.09 and 5.80%. The limit of quantitation for OTC and TC in salmon muscle was 50 μg/kg.

scholarly journals Determination of Nonylphenol and Octylphenol Ethoxylates in Effluent by Liquid Chromatography with Fluorescence Detection

1997 ◽  
Vol 80 (2) ◽  
pp. 401-407 ◽  
Author(s):  
Lindsey G Mackay ◽  
Marguerite Y Croft ◽  
David S Selby ◽  
Robert J Wells
Keyword(s):  
Fluorescence Detection ◽  
Nonionic Surfactants ◽  
Solid Phase ◽  
Graphitized Carbon Black ◽  
Phase Extraction ◽  
Matrix Interferences ◽  
Graphitized Carbon ◽  
Cleanup Procedure ◽  
Liquid Chromatographic

Abstract A robust liquid chromatographic (LC) method with fluorescence detection is described for the simultaneous determination of the nonionic surfactants nonylphenol ethoxylates (NPEO) and octylphenol ethoxylates (OPEO) in effluent samples from sewerage treatment plants. The cleanup procedure uses graphitized carbon black solid-phase extraction cartridges. A subsequent derivatization step removes matrix interferences that are no longer fluorescent after acetylation. The efficiency of the method is monitored by inclusion of a surrogate compound designed and synthesized specifically for this purpose. The limit of reporting for the method is 5 μg/L for 100 mL effluent samples. Studies on confirmation of identity of NPEO and OPEO by electrospray LC/mass spectrometry are described.

Liquid Chromatographic Method for Rapid Determination of Total Avermectin B1 and 8,9-Z-Avermectin B1 Residues in Apples

1995 ◽  
Vol 78 (2) ◽  
pp. 419-422 ◽  
Author(s):  
Janice A Cobin ◽  
Nelson A Johnson
Keyword(s):  
Chromatographic Method ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Rapid Determination ◽  
Reversed Phase ◽  
Extraction Column ◽  
Liquid Chromatographic Method ◽  
Limit Of Quantitation ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method has been developed and validated for the rapid determination of avermectin B1 and 8,9-Z-avermectin B1 residues in apples. The avermectins are extracted from the crop matrix with an acetonitrile–water–hexane mixture; the extract is cleaned up on an aminopropyl solid-phase extraction column. The avermectins are derivatized with trifluoroacetic anhydride and analyzed by reversed-phase liquid chromatography with fluorescence detection. Recoveries of avermectins from apples fortified with about 2–77 ppb avermectin B1a or 2-27 ppb 8,9-Z-avermectin B1a averaged 85%. The limit of quantitation is 2 ppb (signal- to-noise [S/N] ratio, 12) and the limit of detection is 1 ppb (S/N ratio, 6) for each analyte. The assay is a simple, rapid, and sensitive method for monitoring the total amount of avermectin residues in apples.

scholarly journals Determination of Total Avermectin B1 and 8,9-Z-Avermectin B1 Residues in Wine by Liquid Chromatography

1996 ◽  
Vol 79 (5) ◽  
pp. 1158-1161 ◽  
Author(s):  
Janice A Cobin ◽  
Nelson A Johnson
Keyword(s):  
Liquid Chromatography ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Signal To Noise Ratio ◽  
Reversed Phase ◽  
Liquid Chromatographic Method ◽  
Limit Of Quantitation ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method was developed and validated for determination of avermectin Bi and 8,9-Z-avermectin B1 residues in wine. The sample is extracted with hexane-acetonitrile and the hexane layer containing the avermectins is concentrated/ purified on an aminopropyl solid-phase extraction (SPE) column. The purified extract is derivatized with trifluoroacetic anhydride and the derivatized avermectins are analyzed by reversed-phase liquid chromatography with fluorescence detection. Recoveries of avermectins from wine fortified with approximately 1-25 ng/g avermectin B1a or 8,9-Zavermectin B1a averaged 88 and 102%, respectively. The limit of quantitation is 1 ng/g (signal-to-noise ratio [S/N] > 10) and the limit of detection is 0.5 ng/g (S/N > 3) for each analyte. This procedure provides a simple, rapid, and sensitive method for monitoring the total amount of avermectin residues in wine.

Liquid Chromatographic Method for Determination of Total Avermectin Bi and 8,9-Z-Avermectin B1 Residues in Hops

1996 ◽  
Vol 79 (2) ◽  
pp. 503-507 ◽  
Author(s):  
Janice A Cobin ◽  
Nelson A Johnson
Keyword(s):  
Chromatographic Method ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Signal To Noise Ratio ◽  
Extraction Column ◽  
Assay Procedure ◽  
Liquid Chromatographic Method ◽  
Limit Of Quantitation ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method has been developed and validated for determination of avermectin B1 and 8,9-Z-avermectin B1 residues in dried hops. The dried hops are rehydrated and subsequently extracted with a methanol-water mixture.The aver- mectins are partitioned into hexane and the hexane extract is concentrated (purified) on an amino- propyl solid-phase extraction column. The purified extract is derivatized with trifluoroacetic anhydride, and the derivatized avermectins are analyzed by re versed-phase liquid chromatography with fluorescence detection. Recoveries of the avermectins fromdried hops fortified with approximately 51000 ng/g avermectin B1a or 8,9-Z-avermectin B1a ranged from 73 to 108% with an overall average recovery of 95%. The limit of quantitation is 5 ng/g (signal-to-noise ratio [S/N] > 10), and the limit of detection is 2 ng/g (S/N > 3) for each analyte. The assay procedure provides a simple, rapid, and sensitive method for monitoring the total avermectin residues in hops.

scholarly journals Determination of Residues of Azamethiphos in Salmon Tissue by Liquid Chromatography with Fluorescence Detection

1999 ◽  
Vol 82 (5) ◽  
pp. 1224-1228 ◽  
Author(s):  
Allen P Pfenning ◽  
José E Roybal ◽  
Sherri B Turnipseed ◽  
Steve A Gonzales ◽  
Jeffrey A Hurlbut
Keyword(s):  
Fluorescence Detection ◽  
Mobile Phase ◽  
Anhydrous Sodium Sulfate ◽  
Solid Phase ◽  
Target Level ◽  
Method Detection Limit ◽  
Standard Curve ◽  
Limit Of Quantitation ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method with fluorescence detection (FLD) is described for determining residues of the pesticide azamethiphos (AZA) in salmon tissue. The sample is extracted with ethyl acetate, centrifuged, dehydrated with anhydrous sodium sulfate, evaporated, reconstituted in water, and defatted with hexane. The aqueous phase is passed through a C18 solid-phase extraction (SPE) column. The SPE column is eluted with methanol, and the eluate is evaporated to dryness and then taken up in 10% acetonitrile (ACN) in water. The analyte is determined by LC using a C18 column, ACN-H2O (32 + 68) mobile phase, and FLD with excitation at 230 nm and emission at 345 nm. Composited salmon tissues were fortified with AZA at 5,10,21, 42, and 83 ng/g or ppb (target level, X = 10 ng/g). Overall recoveries were 86%, with between-day variability of 5.3%. The method detection limit was calculated as 1.2 ppb AZA based on a 5 g sample. The limit of quantitation as determined empirically by this method is the lower limit of the standard curve, approximately 5 ppb.

scholarly journals Multiresidue Determination of Eleven Quinolones in Milk by Liquid Chromatography with Fluorescence Detection

2005 ◽  
Vol 88 (6) ◽  
pp. 1688-1694 ◽  
Author(s):  
Guixiang Yang ◽  
Baoyin Lin ◽  
Zhenling Zeng ◽  
Zhangliu Chen ◽  
Xianhui Huang
Keyword(s):  
Fluorescence Detection ◽  
Solid Phase ◽  
Gradient Elution ◽  
Reversed Phase ◽  
Phase Gradient ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
Multiresidue Determination ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method with fluorescence detection was developed for simultaneous determination of norfloxacin, ofloxacin, ciprofloxacin, pefloxacin, lomefloxacin, danofloxacin, enrofloxacin, sarafloxacin, difloxacin, oxolinic acid, and flumequine in milk. The samples were extracted with 10% trichloroacetic acid/acetonitrile (9 + 1, v/v) and cleaned by Strata-X reversed-phase solid-phase extraction cartridges. The 11 quinolones were separated on a reversed-phase C18 column (Hypersil BDS-C18) with mobile phase gradient elution and detected with fluorescence by means of a wavelength program. The recoveries for milk fortified with the 11 quinolones at 3 levels were 69–88%, with acceptable relative standard deviations of <9% (intraday) and <14% (interday). The limits of detection were 23 μg/L for enrofloxacin, and 1–9 μg/L for the other 10 quinolones.

Liquid Chromatographic Determination of Amiodarone Hydrochloride and Related Compounds in Raw Materials and Tablets

1994 ◽  
Vol 77 (6) ◽  
pp. 1447-1453 ◽  
Author(s):  
Pauline M Lacrok ◽  
Norman M Curran ◽  
Wing-Wah Sy ◽  
Dennis K J Goreck ◽  
Pierre Thibault ◽  
...  
Keyword(s):  
Raw Materials ◽  
Chromatographic Determination ◽  
Raw Material ◽  
Liquid Chromatographic Method ◽  
Limit Of Quantitation ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Amiodarone Hydrochloride ◽  
Related Compounds

Abstract A liquid chromatographic method for the determination of amiodarone hydrochloride and 10 related compounds in drug raw material and for assay of drug in tablets was developed. The method specifies a 3 jxm Hypersil nitrile column (150 × 4.6 mm), a mobile phase of 1 + 1 acetonitrile–ammonium acetate buffer (0.1 M adjusted to pH 6.0 with 0.1 M acetic acid), a flow rate of 1 mL/min, and detection at 240 nm. The lower limit of quantitation of the related compounds is 0.02% or less. Drug contents in 2 raw material samples were 100.1 and 99.9% and ranged from 98.2 to 99.4% in 3 tablet formulations. Impurity levels in 2 samples of raw material from different manufacturers were ca 0.4%. The presence of 3 of the known related compounds in these samples was confirmed by liquid chromatographymass spectrometry. The method applied to raw materials was evaluated by a second laboratory and found to be satisfactory.

scholarly journals Determination of Halofuginone and Amprolium in Chicken Muscle and Egg by Liquid Chromatography

2001 ◽  
Vol 84 (1) ◽  
pp. 43-46 ◽  
Author(s):  
Yuzo Yamamoto ◽  
Fusao Kondo
Keyword(s):  
Lower Limit ◽  
Solid Phase ◽  
Lauryl Sulfate ◽  
Ultraviolet Detection ◽  
Chicken Egg ◽  
Chicken Muscle ◽  
Limit Of Determination ◽  
Cleanup Procedure ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method was developed for simultaneous measurement of halofuginone (HFN) and amprolium (APL) in chicken muscle and egg. HFN and APL were extracted from chicken muscle and egg with acetonitrile. In chicken egg, they were partially purified by solid-phase extraction (SPE) to separate them from impurities. The LC separation was performed on a 4.6 mm id × 250 mm TSK-gel ODS-80TM column using acetonitrile–McIlvaine buffer, pH 3.4, containing 0.01M sodium lauryl sulfate (42 + 58) as the mobile phase. Ultraviolet detection of HFN and APL was performed at wavelengths of 242 and 265 nm, respectively. Recoveries of HFN and APL from chicken muscle spiked at 0.5 μg/g were 74.8 ± 17.7 and 94.2 ± 5.0%, respectively (mean ± standard deviation [SD], n = 10). In chicken muscle, the lower limit of determination for both APL and HFN was 0.03 μg/g. Recoveries of HFN and APL from chicken egg spiked at 0.5 μg/g by a cleanup procedure using SPE were 54.6 ± 3.4 and 85.0 ± 2.4%, respectively (mean ± SD, n = 5). In chicken egg, the lower limit of determination for both APL and HFN was 0.04 μg/g.

scholarly journals Determination of Small Amounts of Niacin in Vinegar: Comparison of Liquid Chromatographic Method with Microbiological Methods

1998 ◽  
Vol 81 (6) ◽  
pp. 1273-1276 ◽  
Author(s):  
Shuji Hirayama
Keyword(s):  
Positive Error ◽  
Titrimetric Method ◽  
Turbidimetric Method ◽  
Coefficients Of Variation ◽  
Microbiological Methods ◽  
Liquid Chromatographic Method ◽  
Cleanup Procedure ◽  
Liquid Chromatographic ◽  
Rice Vinegar

Abstract An LC method using a new cleanup technique was compared with 2 microbiological methods for determining small amounts of niacin in vinegar. Coefficients of variation for grain vinegar and rice vinegar were 8.33 and 5.3%, respectively, with the LC method, 5.26 and 2.0% with the titrimetric method, and 5.55 and 7.11 % with the turbidimetric method. Among the 3 methods, titrimetry was the most precise. The turbidimetric method tended to yield greater positive error than the titrimetric method. On the other hand, the titrimetric method requires a longer incubation period (72 h) than the turbidimetric method. The LC method using the new cleanup procedure may be useful for routine analysis of small amounts of niacin in vinegars.

scholarly journals Application of a Mixed-Mode Solid-Phase Extraction and Cleanup Procedure for LC/MS Determination of Thiabendazole and Carbendazim in Apple Juice

2001 ◽  
Vol 84 (5) ◽  
pp. 1608-1614 ◽  
Author(s):  
Michael S Young ◽  
Michael F Early ◽  
Claude R Mallet ◽  
Jim Krol
Keyword(s):  
Solid Phase Extraction ◽  
Mixed Mode ◽  
Apple Juice ◽  
Solid Phase ◽  
Ionization Mass ◽  
Phase Extraction ◽  
Cleanup Procedure ◽  
Sample Preparation Procedure ◽  
Liquid Chromatographic

Abstract Recently, a mixed-mode solid-phase extraction (SPE) procedure was developed for rapid extraction and cleanup for determination of the fungicides thiabendazole and carbendazim in various fruit juices. This paper reports the application of that sample preparation procedure to the liquid chromatographic/mass spectrometric determination of these fungicides in apple juice with detection by positive electrospray ionization mass spectrometry (ESI/MS). Response was linear for sample concentrations from 2 to 500 μg/L (ppb). Recoveries averaged 74% (9% RSD) for carbendazim and 93% (9% RSD) for thiabendazole. After SPE cleanup, no matrix supression was observed for the ESI+ response for either compound studied. The method was applied to the analysis of incurred residues in 4 store-bought apple juices; carbendazim levels ranged from 10 to 70 μg/L and thiabendazole levels ranged from less than 2 to 130 μg/L.

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