Regulatory Approach to Determination of Lysine in Feedstuffs by Liquid Chromatography with Fluorescence Detection via Precolumn Dansylation

1989 ◽  
Vol 72 (4) ◽  
pp. 609-613 ◽  
Author(s):  
Alan Thio ◽  
David H Tompkins
Keyword(s):  
Liquid Chromatography ◽  
Animal Feed ◽  
Internal Standard ◽  
Internal Standard Method ◽  
Fluorescence Detector ◽  
The Matrix ◽  
Regulatory Approach ◽  
Small Aliquot ◽  
Calculated Amount

Abstract A method for compliance analysis for total lysine in animal feed is described. One g portions of finely ground feed sample are spiked with a calculated amount of diaminobutyric acid internal standard and hydrolyzed by heating with 100 mL 6N aqueous HC1 at 120°C in a closed bottle. A very small aliquot (25 /*L) of hexane-washed hydrolysate is evaporated under vacuum to dryness and derivatized with dansyl chloride. Lysine is separated from other amino acids by isocratic reverse-phase (LC-18) liquid chromatography; the mobile phase is acetonitrile-O.OlM sodium phosphate (pH 7.0) buffer (100 + 210, v/v). The internal standard method along with a fluorescence detector (310-410 nm excitation and 435-650 nm emission), is used for quantitation. Thirty-five feed samples of various types (lysine 0.2- 8.2%) were analyzed with no interference from the matrix. The results were compared with those furnished by an independent laboratory using an amino acid analyzer; no statistical difference was found at the 95% confidence level. Six replicate analyses of a feed sample showed a coefficient of variation of 2.8%; no significant differences were found when between-day results of 9 samples (lysine 0.90- 4.30%) were compared. This procedure has been tested for ruggedness and can be applied for compliance determination of total lysine in feedstuffs by laboratories with limited resources

scholarly journals Simultaneous Determination of Bergapten, Imperatorin, Notopterol, and Isoimperatorin in Rat Plasma by High Performance Liquid Chromatography with Fluorescence Detection and Its Application to Pharmacokinetic and Excretion Study after Oral Administration of Notopterygium incisum Extract

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
John Teye Azietaku ◽  
Xie-an Yu ◽  
Jin Li ◽  
Jia Hao ◽  
Jun Cao ◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Simultaneous Determination ◽  
Fluorescence Detection ◽  
High Performance ◽  
Internal Standard ◽  
Rat Plasma ◽  
Fluorescence Detector ◽  
Excretion Study

A specific, sensitive, and reliable high performance liquid chromatography with fluorescence detection (HPLC-FLD) was first optimized and then used in the simultaneous quantification of bergapten, imperatorin, notopterol, and isoimperatorin in rat plasma using osthole as the internal standard. Liquid-liquid extraction with ethyl acetate was employed in treating the rat plasma samples obtained. Separation was carried out with a Hedera™ ODS column (4.6 × 250 mm, 5 μm) by gradient elution at a temperature of 40°C. Excitation and emission of the fluorescence detector were set to 300 and 490 nm, respectively. The lower limits of quantification for bergapten, imperatorin, notopterol, and isoimperatorin in rat plasma were 4, 40, 4, and 2 ng mL−1, respectively. The intraday and interday precision and accuracy for the four coumarins were within acceptable criteria. The recovery of the method was satisfactory with a range of 80.3–114%. The validated method was successfully used for the simultaneous determination of the four coumarins in Notopterygium incisum extracts and also for the pharmacokinetic and excretion study of bergapten, imperatorin, notopterol, and isoimperatorin in rats.

Determination of Ochratoxin A in Animal Feed and Cereal Grains by Liquid Chromatography with Fluorescence Detection

1986 ◽  
Vol 69 (6) ◽  
pp. 957-959 ◽  
Author(s):  
Huguette Cohen ◽  
Michel Lapointe
Keyword(s):  
Acetic Acid ◽  
Liquid Chromatography ◽  
Ochratoxin A ◽  
Fluorescence Detection ◽  
Animal Feed ◽  
Cereal Grains ◽  
Fluorescence Detector ◽  
Animal Feeds ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method is described for determination of ochratoxin A in animal feeds and cereal grains. Samples are initially extracted with chloroform-ethanol (8 + 2) and 5% acetic acid in water. Extracts are purified using a silica gel cartridge followed by a cyano cartridge. The samples are evaporated, diluted to a known volume, and analyzed using a 10 cm column of 3 μm Cm and a fluorescence detector. The method was applied to a variety of animal feeds and cereal grains at levels of 1.0-0.005 ppm added ochratoxin A. The overall recovery was 90.6% ± 3.6.

Determination of Fourteen Sulfonamides Residues in Penaeus vannamei by High Performance Liquid Chromatography Coupled with Post-Column Derivation

2013 ◽  
Vol 781-784 ◽  
pp. 903-907
Author(s):  
Dong Mei Huang ◽  
Jie Xu ◽  
Yong Fu Shi ◽  
Xuan Yun Huang ◽  
Huan Yu ◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Internal Standard ◽  
Standard Addition ◽  
Quantitative Detection ◽  
Penaeus Vannamei ◽  
Fluorescence Detector ◽  
Relative Standard

The method was established to detect fourteen sulfonamides residuces in Penaeus vannamei by high performance liquid chromatography coupled with post-column derivation. Sulfonamides residues were extracted with ethyl acetate after adding sulfapyridine as internal standard. The extract was concentrated.The residues were transferred to hydrochloric acid solution. The solution was defatted with n-hexane. The compounds were detected by HPLC with fluorescence detector .The standard addition method was used. The calibration curves were linear. The recoveries ranged from 77.8% to 103.6%. The relative standard deviations were all below 9.1%. Quantitative detection limits of fourteen sulfanomides ranged from1.0μg/kg to 5.0μg/kg. Results indicated that the method was easier, faster and more accurate.

scholarly journals Determination of ethinylestradiol and levonorgestrel in oral contraceptives with HPLC methods with UV detection and UV/fluorescence detection

2006 ◽  
Vol 52 ◽  
pp. 9-16
Author(s):  
Zorica Arsova-Sarafinovska ◽  
Liljana Ugrinova ◽  
Katerina Starkoska ◽  
Dragan Djordjev ◽  
Aneta Dimitrovska
Keyword(s):  
Fluorescence Detection ◽  
Oral Contraceptives ◽  
Standard Method ◽  
Internal Standard ◽  
Hplc Method ◽  
Uv Detection ◽  
Internal Standard Method ◽  
Fluorescence Detector ◽  
Uv Fluorescence

Oral contraceptives are pharmaceutical formulations containing an estrogen in a small amount and a synthetic progestin in 5-30 times bigger amount. A sensitive, accurate and rapid method for determination of active compounds is required. We have developed HPLC methods for determination of ethinylestradiol (EED) and levonorgestrel (LNG) in commercially available tablets. Chromatographic separation was performed on a Purospher® STAR RP-18e reversed-phase column (150 X 4.0 mm I.D.; particle size 5 µm) in an isocratic mode with a mobile phase constituted of 47% acetonitrile: 53% water (V/V) for both methods. The elution was carried out at a flow rate of 1.50 ml /min. All analyses were performed at room temperature (24 +/- 2°C). In the HPLC method with UV detection (internal standard method) both compounds were detected at 215 nm. Drospirenone was used as an internal standard. In HPLC method with UV/fluorescence detection (external standard method) LNG was monitored at 242 nm, while EED was detected with fluorescence detector at 310 nm (excitation 285 nm). The methods’ performances were fully validated by a determination of linearity, reproducibility, accuracy and sensitivity. Both methods were applied for determination of Uniformity of Dosage Units. The results obtained with both methods were highly comparable. However, the HPLC method with UV/ fluorescence detection has showed superior sensitivity for EED indicated by 83 times lower detection limit. HPLC method with UV/ fluorescence detection could be recommended as a method of choice for determination of ethinylestradiol, present at a very low dosage level in low-dose oral contraceptives, that also contain bigger amount of synthetic progestin.

scholarly journals Determination and Separation of Diarylheptanoids From Alder Growing in Latvia

2015 ◽  
Vol 1 ◽  
pp. 329 ◽  
Author(s):  
Liga Roze ◽  
Oskars Bikovens ◽  
Galina Telysheva
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Quantitative Determination ◽  
High Performance ◽  
Internal Standard ◽  
Extraction Methods ◽  
Internal Standard Method ◽  
Black Alder ◽  
Phenolic Components

The composition of diarylhepatnoids fraction isolated from bark of two alder species (grey alder and black alder) was studied. The efficiency of three extraction methods used for isolation of diarylhepatnoids from alder bark was compared. Two diarylhepatnoids: 1,7-bis-(3,4-dihydroxyphenyl)-heptan- 3-one-5-O-β-D-xylopyronoside (oregonin) and 1,7-bis-(3,4-dihydroxyphenyl)-3-hydroxyheptane-5-O-β-D- xylopyranoside were isolated from the bark of grey alder. The phenolic components of the extracts were analyzed by high-performance liquid chromatography (HPLC). Quantitative determination of oregonin was performed using an internal standard method. The results obtained show that alder barks are rich source of diarylhepatnoids.

A simple and sensitive high performance liquid chromatography assay with a fluorescence detector for determination of canagliflozin in human plasma

2015 ◽  
Vol 7 (7) ◽  
pp. 3028-3035 ◽  
Author(s):  
Muzaffar Iqbal ◽  
Nasr Y. Khalil ◽  
Amer M. Alanazi ◽  
Khalid A. Al-Rashood
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Human Plasma ◽  
High Performance ◽  
Internal Standard ◽  
Hplc Assay ◽  
Fluorescence Detector ◽  
Accurate Quantification

Simple and sensitive HPLC assay for accurate quantification of canagliflozin in human plasma using telmisartan as the internal standard.

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