Automated Liquid Chromatographic Determination Of Aflatoxin Mi In Milk Using On-Line Dialysis For Sample Preparation

1990 ◽  
Vol 73 (6) ◽  
pp. 969-973
Author(s):  
Louis G.M Th.Tuinstra ◽  
Paul G.M Kienhuis ◽  
Peter Dols
Keyword(s):  
Automated Analysis ◽  
Chromatographic Determination ◽  
Aflatoxin M1 ◽  
Stopped Flow ◽  
Reverse Phase ◽  
On Line ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Flow Dialysis

Abstract A procedure has been developed for the automated Isolation of aflatoxin M1 from decreamed milk. The method uses online stopped flow dialysis and subsequent trace enrichment on a reverse-phase column. After a back-flush to the analytical liquid chromatography column, aflatoxin M1 is determined with fluorescence detection. Fully automated analysis Is possible with reproducible dialysis recoveries above 50% (CV = 7.5%, n = 25 at the 50 ng/kg level) and determination levels of 20 ng/kg within 20 mln.

Effects of Injection Solvent and Mobile Phase on Efficiency in Reverse-Phase Liquid Chromatographic Determination of Aflatoxin M1

1990 ◽  
Vol 73 (1) ◽  
pp. 69-70 ◽  
Author(s):  
Rodney W Beaver
Keyword(s):  
Mobile Phase ◽  
Chromatographic Determination ◽  
Aflatoxin M1 ◽  
Mobile Phase Composition ◽  
Reverse Phase ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic ◽  
Theoretical Plates

Abstract The effects of Injection solvent and mobile phase composition on the reverse-phase liquid chromatographic determination of aflatoxin M1 (M1) were examined. M1 was converted to the more highly fluorescent derivative aflatoxin M2a (M2a)- Using a C-18 column and a mobile phase of H20-MeCNMeOH (60 + 20 + 20) (MP-A), M2a was dissolved in various ratios of MeCN-H20 prior to Injection. Chromatographic efficiency for the M2a peak varied from ca 2000 theoretical plates when injected in 30% aqueous MeCN to ca 9000 plates when injected in water alone. However, using the same C-18 column but with a mobile phase of H20-IPAMeCN (80 + 12 + 8) (MP-B), the M2a peak exhibited 25000 plates when injected in 30% aqueous MeCN and 10000 plates when injected in water alone.

Liquid Chromatographic Determination of Zoalene in Medicated Feeds

1984 ◽  
Vol 67 (5) ◽  
pp. 861-862 ◽  
Author(s):  
John Morawski ◽  
Glenn Kyle
Keyword(s):  
Colorimetric Method ◽  
Chromatographic Determination ◽  
Activated Alumina ◽  
Reverse Phase ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Aoac Official ◽  
Liquid Chromatographic ◽  
Medicated Feeds

Abstract A rapid, reliable separation and quantitation of zoalene (3,5-dinitroo-toluamide) from feeds is accomplished by using reverse phase liquid chromatography (LC) and ultraviolet detection. An extraction technique which is similar to the present AOAC official colorimetric method is used before chromatographic analysis. This extraction is followed by an activated alumina cleanup and LC to separate zoalene from feed matrix. The methodology was applied to a variety of spiked feed matrices, and yielded good recoveries. Liquid chromatographic results were shown to correlate with colorimetric determinations.

Reverse Phase Liquid Chromatographic Determination of Chlorophacinone and Diphacinone in Bait Formulations

1982 ◽  
Vol 65 (4) ◽  
pp. 927-929
Author(s):  
Brian R Bennett ◽  
Gregory S Grimes
Keyword(s):  
Acetic Acid ◽  
Glacial Acetic Acid ◽  
Chromatographic Determination ◽  
Reverse Phase ◽  
Target Concentration ◽  
External Standard ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract Chlorophacinone and diphacinone are extracted at the 0.005% level from grain or paraffinized baits with glacial acetic acid. The target concentration is 0.01 mg/mL. The filtered supernate is chromatographed on a Partisil PXS ODS10/25 liquid chromatography column with premixed and degassed glacial acetic acid-tetrahydrofuran-water (14 + 2 + 9) and detected at 288 nm. The concentration is calculated by using an external standard. The recovery from spiked samples averaged 96.6% for both analytes. The response is linear from 0.001 to 0.040 mg/mL. The coefficient of variation of within-day replicates ranged from 1.1 to 2.5%.

Liquid Chromatographic Determination of Diazepam in Tablets: Collaborative Study

1985 ◽  
Vol 68 (3) ◽  
pp. 545-546
Author(s):  
Michael Tsougros
Keyword(s):  
Collaborative Study ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Reverse Phase ◽  
Photometric Detection ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
The Mean ◽  
Liquid Chromatographic

Abstract A stability indicating liquid chromatographic method for the determination of diazepam in tablets was collaboratively studied by 6 laboratories. The method uses a Cig reverse phase column, a methanolwater mobile phase, p-tolualdehyde as the internal standard, and photometric detection at 254 nm. The collaborators were supplied with a synthetic tablet powder and 3 commercial tablet samples. The mean recovery of diazepam from the synthetic tablet powder was 100.2%. For all samples analyzed, the coefficient of variation was < 1.5%. The method has been adopted official first action.

Liquid Chromatographic Determination of Sulfite in Grapes and Selected Grape Products

1989 ◽  
Vol 72 (6) ◽  
pp. 903-906
Author(s):  
Gracia A Perfetti ◽  
Frank L Joe ◽  
Gregory W Diachenko
Keyword(s):  
Chromatographic Determination ◽  
Reverse Phase ◽  
Nitrobenzoic Acid ◽  
Tetrabutylammonium Ion ◽  
Aqueous Formaldehyde Solution ◽  
Liquid Chromatographic Determination ◽  
Aoac Official ◽  
Liquid Chromatographic ◽  
Aqueous Formaldehyde

Abstract A liquid chromatographic (LC) method is described for the determination of sulfite in grapes and certain grape products. Sulfite is extracted from grapes with aqueous formaldehyde solution buffered at pH 5; free sulfite is converted to hydroxymethylsulfonate (HMS), which is extremely stable at pH 3-7. Subsequent heating to 80°C for 30 min converts reversibly bound forms of sulfite to HMS. The extract is then analyzed by reverse-phase ion-pairing liquid chromatography, using a Cjg column and a mobile phase of aqueous 0.005M tetrabutylammonium ion in 0.05M acetate, pH 4.7, and a flow rate of 1 mL/min. Aqueous KOH is added to the eluate to convert HMS to free sulfite, which is then treated with 5,5'-dithiobis[2-nitrobenzoic acid]. This reaction produces the 3-carboxy-4-nitrothiophenolate anion, which is determined by measurement of electronic absorption at 450 nm. For grapes spiked with HMS at 5-20 ppm (as S02), recoveries ranged from 92 to 112%, with a coefficient of variation of 4.6%. The method was also used to determine sulfite in various grape products. Results were comparable to those obtained by the AOAC official Monier-Williams method.

Liquid Chromatographic Determination of Cinnamic and Benzoic Acids in Benzoin Preparations

1987 ◽  
Vol 70 (4) ◽  
pp. 689-691
Author(s):  
Abdel-Aziz M Wahbi ◽  
Mohammad A Abounassif ◽  
El-Rasheed A Gad-Kariem ◽  
Mahmoud W Ibrahim
Keyword(s):  
Chromatographic Determination ◽  
Cinnamic Acids ◽  
Reverse Phase ◽  
British Pharmacopoeia ◽  
Liquid Chromatographic Method ◽  
Individual Determination ◽  
Liquid Chromatographic Determination ◽  
The Individual ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method for the individual determination of benzoic and cinnamic acids in 2 benzoin preparations is presented. The method specifies a reverse phase column and 0.01M KH2P04- methanol (85 + 15) as mobile phase at a flow rate of 1.8 mL/min, with detection at 254 nm. The method has been applied to 2 benzoin preparations and the results were compared with those from the British Pharmacopoeia method.

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