scholarly journals Liquid Chromatographic Method for Determining the Concentration of Bisazir in Water

1997 ◽  
Vol 80 (5) ◽  
pp. 1111-1116 ◽  
Author(s):  
Ronald J Scholefield ◽  
Karen S Slaght ◽  
John L Allen
Keyword(s):  
Great Lakes ◽  
Solid Phase ◽  
Reversed Phase ◽  
Lake Huron ◽  
Extraction Column ◽  
Treated Effluent ◽  
Liquid Chromatographic Method ◽  
Sea Lampreys ◽  
Liquid Chromatographic ◽  
Reversed Phase Lc

Abstract Barrier dams, traps, and lampricides are the techniques currently used by the Great Lakes Fishery Commission to control sea lampreys {Petromyzon marinug) in the Great Lakes. To augment these control techniques, a sterile-male-release research program was initiated at the Lake Huron Biological Station. Male sea lampreys were sterilized by intraperitoneal injection of the chemical sterilant P,P-bis(1-aziridinyl)-Nmethylphosphinothioic amide (bisazir). An analytical method was needed to quantitate the concentration of bisazir in water and to routinely verify that bisazir (>25 μg/L) does not persist in the treated effluent discharged from the sterilization facility to Lake Huron. A rapid, accurate, and sensitive liquid chromatographic (LC) method was developed for determining bisazir in water. Bisazir was dissolved in Lake Huron water; extracted and concentrated on a C18 solid-phase extraction column; eluted with methanol; and quantitated by reversed-phase LC using a Cis column, amobile phase of 70% water and 30% methanol (v/v), and UV detection (205 nm). Bisazir retention time was 7-8 min; total run time was about 20 min. Method detection limit for bisazir dissolved in Lake Huron water was about 15 μg/L. Recovery from Lake Huron water fortified with bisazir at 100 μg/L was 94% (95% confidence interval, 90.2-98.2%).

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.

Gradient Multipeak Liquid Chromatographic Method for Determination of Ardacin in Bulk Chemical and Premix Formulations

1995 ◽  
Vol 78 (2) ◽  
pp. 289-293
Author(s):  
Hafez Abdel-Kader ◽  
Myriam M Kobylkevich ◽  
Larry S Wigman ◽  
Govind K Menon
Keyword(s):  
Pilot Scale ◽  
Reversed Phase ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
External Standard ◽  
Bulk Chemical ◽  
Method Accuracy ◽  
Liquid Chromatographic ◽  
Reversed Phase Lc

Abstract A liquid chromatographic (LC) method was developed for the determination of ardacin in bulk chemical (78 to 100%, w/w anhydrous) and premix formulations (3.3 to 26.4%, w/w). The method is based on reversed-phase LC resolution of ardacin components and detection by UV absorbance at 220 nm. Ardacin has 10 components, and each component can be quantitated separately. Total ardacin is determined by summing the areas of the 10 component peaks. Calculations are performed using an external standard approach. The method is linear for ardacin at 50 to 150 μ/mL. The method accuracy for a typical bulk chemical is ± 1.5%, w/w (relative standard deviation [RSD], 1.6%), and recovery from a typical pilot scale premix is 99.9% (RSD, 3.4%). The method is useful for monitoring stability during storage.

High-performance liquid-chromatographic method compared with a modified radioimmunoassay of cotinine in plasma

1991 ◽  
Vol 37 (11) ◽  
pp. 1989-1993 ◽  
Author(s):  
S L Perkins ◽  
J F Livesey ◽  
E A Escares ◽  
J M Belcher ◽  
D K Dudley
Keyword(s):  
High Performance ◽  
Solid Phase ◽  
Plasma Concentrations ◽  
Potassium Phosphate ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Liquid Chromatographic Method ◽  
Assay Precision ◽  
Liquid Chromatographic ◽  
Interassay Precision

Abstract Cotinine is a sensitive and specific biochemical marker of exposure to cigarette smoke. We describe a simple solid-phase extraction of cotinine from plasma before quantification by HPLC. Extraction recovery was 97.9% +/- 11.0% for plasma concentrations of 5-400 micrograms/L. Baseline separation of cotinine and caffeine was achieved within 11 min of injection onto a C18 reversed-phase column. The mobile phase was citric acid/dibasic potassium phosphate (30 mmol/L each, pH 6.0) containing 100 mL of acetonitrile per liter. Within-day and day-to-day precision (CV) were 4.7% and 8.4%, respectively. We also describe a modification of the Nicotine Metabolite RIA kit (Diagnostic Products Corp.) for quantifying cotinine in plasma. Recovery of cotinine from supplemented plasma was within 10% of the expected value with this RIA kit. Interassay precision averaged 8.1% for samples in the range 50-400 micrograms/L; intra-assay precision averaged 3.6% at 230 micrograms/L and 8.7% at 53 micrograms/L. Correlation between the two methods was RIA = 1.13 HPLC + 14.8 (n = 128, r = 0.957, P less than 0.001). Both methods are technically simple to perform.

Simultaneous Assay of Corticosterone and Cortisol in Plasma by Reversed-Phase Liquid Chromatography

1992 ◽  
Vol 38 (3) ◽  
pp. 346-352 ◽  
Author(s):  
M Hariharan ◽  
S Naga ◽  
T VanNoord ◽  
E K Kindt
Keyword(s):  
Extraction Method ◽  
Solid Phase ◽  
Internal Standard ◽  
Reversed Phase ◽  
Reversed Phase Liquid Chromatography ◽  
Ultraviolet Detector ◽  
Liquid Chromatographic Method ◽  
Analytical Recovery ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract We have developed a simple, specific, and sensitive reversed-phase liquid-chromatographic method for accurate and simultaneous analysis of corticosterone and cortisol in human plasma. We achieved a detection limit of 300 ng/L for both steroids by modifying the old solid-phase extraction method to make use of "Tef Elutor" C18 columns, using a minibore (100 x 2 mm) analytical column, and using an ultraviolet detector with a 10-mm-pathlength flow cell. With the new extraction method absolute extraction efficiencies were greater than 90% for all the analytes, including the internal standard, flumethasone. The mobile phase was water (containing 5 mL of triethylamine per liter and citric acid to adjust the pH to 6.5), tetrahydrofuran, and acetonitrile (82/10/8 by vol). The average interassay CV for corticosterone at 0-25 micrograms/L was 6.5%; that for cortisol at 0-300 micrograms/L was 3.8%. The analytical recovery relative to the internal standard was 100.2% for cortisol and 102.6% for corticosterone. Possible interferences from drugs and other steroids were studied.

Liquid Chromatographic Determination of Sulfadiazine in Salmon by Postcolumn Derivatization and Fluorescence Detection

1995 ◽  
Vol 78 (5) ◽  
pp. 1161-1164 ◽  
Author(s):  
Theresa A Gehring ◽  
Larry G Rushing ◽  
Harold C Thompson
Keyword(s):  
Methylene Chloride ◽  
Coho Salmon ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Solid Phase Extraction Cartridge ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A reversed-phase (ODS-2) liquid chromatographic method was developed to determine low nanogramper-gram levels of sulfadiazine (SDZ) in salmon muscle tissue. SDZ was extracted with acetonitrile-aqueous 2% acetic acid (pH 3.0), partitioned into methylene chloride, and cleaned up by using a strong-cation-exchange, solid-phase extraction cartridge. SDZ was derivatized postcolumn with fluo-rescamine and detected by fluorescence. The limit of detection was 0.2 ng SDZ/g tissue. Recoveries from coho salmon tissue fortified with 1,5,10, and 20 ng SDZ/g tissue averaged 84.5,85.0,83.6, and 83.9%, respectively; recoveries from Atlantic salmon tissue fortified with 10 ng SDZ/g tissue averaged 82.6%.

scholarly journals High-Performance Liquid Chromatographic Method for the Determination of Moniliformin in Corn

1998 ◽  
Vol 81 (5) ◽  
pp. 999-1004 ◽  
Author(s):  
Célestin Munimbazi ◽  
Lloyd B Bullerman
Keyword(s):  
High Performance ◽  
Chromatographic Method ◽  
Solid Phase ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Detector Response ◽  
Dihydrogen Phosphate ◽  
Sodium Dihydrogen Phosphate ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic

Abstract A high-performance liquid chromatographic method using UV absorption was developed for determining moniliformin in corn. The toxin was extracted with water containing 1 % tetrabutylammonium hydrogen sulfate (w/v). Paired moniliformin was partitioned into dichloromethane, which was evaporated to dryness at 50 C. The residue was dissolved in water and applied to a disposable stronganion exchange solid-phase extraction tube. Adsorbed moniliformin was eluted from the tube with 0.05M sodium dihydrogen phosphate monohydrate (pH 5). It was determined by ion-pair reversed-phase chromatography and UV measurement at 229 nm. The minimum detectable amount of pure moniliformin was 0.25 ng/injection (signal-to-noise ratio = 3:1). The detector response was linear from 0.25 to at least 20 ng. The limit of determination was 0.025 μg/g corn. Recoveries of moniliformin from corn spiked at 0.025,0.05,0.25, and 1.0 μg/g averaged 96.5,96.2, 97.2, and 97.8% respectively

Determination of Ardacin in Premix, Supplement, and Animal Feed by a Rapid and Sensitive Two-Peak Liquid Chromatographic Method with Correlation to a Gradient Multipeak Liquid Chromatographic Method

1994 ◽  
Vol 77 (6) ◽  
pp. 1341-1346
Author(s):  
Hafez Abdel-Kader ◽  
Sylvia V Fagan ◽  
Govtnd K Menon ◽  
Larry S Wigman ◽  
Frederic Chapin
Keyword(s):  
Chromatographic Method ◽  
Animal Feed ◽  
Reversed Phase ◽  
Protein Supplement ◽  
Cattle Feed ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
Liquid Chromatographic ◽  
Reversed Phase Lc

Abstract A rapid and sensitive 2-peak liquid chromatographic (LC) method is described for extracting and quantitating ardacin in premix, supplement, and animal feed formulations. Ardacin is extracted from the formulations and analyzed after dilution or cleanup by reversed-phase LC with UV detection at 220 nm. The method correlates well with a more information-rich gradient multipeak LC method. Recoveries for premix formulations ranged from 96.8% (relative standard deviation [RSD], 0.8%) to 103.7% (RSD, 1.3%) for laboratory samples spiked at levels ranging from 1.6 to 39.6% ardacin. Recoveries for protein supplement mash formulations ranged from 98.7% of claim (RSD, 4.1%) to 106.0% of claim (RSD, 7.7%) at ardacin levels ranging from 37.5 to 600 mg/lb. Recoveries for cattle feed ranged from 90.0% of claim (RSD, 11.9%) to 105.6% of claim (RSD, 2.7%) at ardacin levels ranging from 4 to 30 g/ton.

Postcolumn Derivatization Liquid Chromatographic Method for Paralytic Shellfish Toxins

1995 ◽  
Vol 78 (2) ◽  
pp. 528-532 ◽  
Author(s):  
Yasukatsu Oshima
Keyword(s):  
Chromatographic Method ◽  
Solid Phase ◽  
Periodate Oxidation ◽  
Reversed Phase ◽  
Mouse Bioassay ◽  
Marine Animals ◽  
Net Charge ◽  
Solid Phase Extraction Cartridge ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic

Abstract More than 20 analogues of saxitoxin occur naturally. An accurate analytical method applicable to all saxitoxins is required because of the recent findings that decarbamoyl toxins and C (N-sulfocarbamoyl- 11-hydroxysulfate) toxins are metabolites of marine animals or major products of some dinoflagellate species. Almost all the toxins could be determined by ion-interaction chromatography on a silica-based reversed-phase (C8) column with postcolumn periodate oxidation and fluorescence detection. Toxin groups of different net charges were separately determined by isocratic elution using different mobile phases. For determination of the saxitoxin group (net charge, 2+) and the gonyautoxin group (net charge, 1+), use of 1-heptanesulfonate as counterion, with or without acetonitrile in the mobile phase, resulted in resolution of decarbamoyl toxins from their carbamate analogues. C toxins having both M-sulfocarbamoyl and 11-hydroxysulfate moieties on the same molecule were completely resolved using the tetrabutylammonium ion. High sensitivity with detection limits ranging from 20 to 110 fmol were achieved as a result of reduced band broadening and optimized reaction conditions. For applications to biological matrixes, a cleanup procedure using a C18 solid-phase extraction cartridge was effective in preventing false peaks. When applied to low-toxicity shellfish, the liquid chromatographic method gave higher values than the standard mouse bioassay, because of underestimation by the bioassay.

A simple liquid-chromatographic method applied to determine caffeine in plasma and tissues.

1988 ◽  
Vol 34 (11) ◽  
pp. 2345-2348 ◽  
Author(s):  
I Biaggioni ◽  
S Paul ◽  
D Robertson
Keyword(s):  
High Pressure ◽  
Extraction Method ◽  
Mobile Phase ◽  
Chromatographic Method ◽  
Solid Phase ◽  
Reversed Phase ◽  
Simple Liquid ◽  
Liquid Chromatographic Method ◽  
The Mean ◽  
Liquid Chromatographic

Abstract In this simple, reliable assay for quantifying caffeine in plasma and tissues, methylxanthines are first partly purified from plasma and acid extracts of tissue by passage through solid-phase columns. The ease of this extraction method permits a relatively large number of samples to be processed daily. Quantification is by reversed-phase high-pressure liquid chromatography (mobile phase: acetic acid/acetonitrile/water, 2/6/92 by vol). Caffeine is eluted in 20 min. The reliability of this method allows its automation. This method has been adapted to measure caffeine in brain and kidney extracts and in as little as 10 microL of plasma. After 10 days of oral administration of caffeine (1 g/L, in drinking water) to six rats, the mean (+/- SEM) concentrations of caffeine in plasma, brain, and kidney were 18.6 +/- 6.0 micrograms/mL, 16.2 +/- 1.5 micrograms/g, and 18.9 +/- 2.0 micrograms/g, respectively. Correlations were linear between concentrations of caffeine in plasma and brain (r = 0.86) and between concentrations in plasma and kidney (r = 0.91). This method should be useful in studying the effects and mechanisms of actions of methylxanthines.

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