Switching Valve Designed For High Pressure Liquid Chromatographic Fraction Collection

1979 ◽  
Vol 62 (6) ◽  
pp. 1355-1357
Author(s):  
William O Landen
Keyword(s):  
High Pressure ◽  
Oil Removal ◽  
High Pressure Liquid Chromatographic ◽  
Liquid Chromatograph ◽  
Switching Valve ◽  
Gel Permeation ◽  
In Series ◽  
High Pressure Liquid Chromatograph ◽  
Pass Through ◽  
Liquid Chromatographic

Abstract The use of a collection valve specifically designed for high pressure liquid chromatography is described. Application of the valve to high pressure gel permeation chromatographic (GPC) separation of oil from the vitamin A active fraction of margarine resulted in efficient oil removal after one pass through 2 μStyragel (100A) columns connected in series. Using the normal collection mode of the high pressure liquid chromatograph, 2 passes through the GPC columns were required to adequately resolve the fractions.

High Pressure Liquid Chromatographic Determination of Xanthomegnin in Corn

1978 ◽  
Vol 61 (3) ◽  
pp. 590-592
Author(s):  
Michael E Stack ◽  
Nathan L Brown ◽  
Robert M Eppley
Keyword(s):  
High Pressure ◽  
Silica Gel ◽  
Chromatographic Determination ◽  
High Pressure Liquid Chromatographic ◽  
Liquid Chromatograph ◽  
High Pressure Liquid Chromatograph ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Layer Chromatography

Abstract A method is described for the detection and quantitative analysis of xanthomegnin in corn samples. Initial extraction with CHCI3 in the presence of 0.5M H3PO4 is followed by additional purification using silica gel column chromatography. A high pressure liquid chromatograph equipped with a microparticle silica gel column and a 405 nm absorbance detector is used for detection and quantitation of the xanthomegnin. The identity of xanthomegnin is confirmed by thin layer chromatography on silica gel plates developed with benzenemethanol- acetic acid (90-(-5+5). The recovery of xanthomegnin added to corn samples at levels of 0.75–9.6 mg/kg averaged 41% with a coefficient of variation of 25%.

High Pressure Liquid Chromatographic Determination of Ochratoxin A and Zearalenone in Cereals

1979 ◽  
Vol 62 (5) ◽  
pp. 1165-1168
Author(s):  
Egon Josefsson ◽  
Tord Möller
Keyword(s):  
High Pressure ◽  
Ochratoxin A ◽  
Chromatographic Determination ◽  
Hplc Method ◽  
High Pressure Liquid Chromatographic ◽  
Liquid Chromatograph ◽  
Ultraviolet Detector ◽  
In Series ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A high pressure liquid chromatographic (HPLC) method has been developed for determining ochratoxin A and zearalenone in cereals. The sample is extracted with phosphoric acid and chloroform. The extract is cleaned by washing on a silica gel column with cyclohexane-ethylene dichlorideethyl ether. After eluting zearalenone with chloroform, ochratoxin A is eluted with chloroformformic acid. Zearalenone is extracted into alkaline solution, washed with chloroform, the pH is adjusted, and the zearalenone is extracted back into chloroform. Ochratoxin A is purified by chromatography on aqueous sodium bicarbonate-Celite. The mycotoxins are determined by using a liquid chromatograph with 2 columns in series packed with Spherisorb ODS 10 μm and 5 μm, respectively. Ochratoxin A is detected with a spectrophotofluorometer, coupled in series with an ultraviolet detector for estimation of zearalenone. Detection limits are 1-5 μg/kg for ochratoxin A and 2 μg/kg for zearalenone.

High Pressure Liquid Chromatography of Zearalenone in Cereals

1978 ◽  
Vol 61 (4) ◽  
pp. 789-792 ◽  
Author(s):  
Tord E Möller ◽  
Egon Josefsson
Keyword(s):  
High Pressure ◽  
Ethyl Ether ◽  
Chromatographic Method ◽  
Ethylene Dichloride ◽  
High Pressure Liquid Chromatographic ◽  
Liquid Chromatograph ◽  
Ultraviolet Detector ◽  
Liquid Chromatographic Method ◽  
In Series ◽  
Liquid Chromatographic

Abstract A high pressure liquid chromatographic method has been developed for determining zearalenone in cereals. The sample is extracted with phosphoric acid and chloroform. The extract is cleaned up by washing on a silica gel column with benzene-hexane or cyclohexaneethylene dichloride-ethyl ether and eluting with chloroform, and further purified by extracting into alkaline solution, washing with water, adjusting pH, and back-extracting into chloroform. Zearalenone is determined by using a liquid chromatograph with 2 columns in series packed with Spherisorb 10 μm ODS and with an ultraviolet detector set at 236 nm. The detection limit of the method is 2 μg/kg. Recovery is about 90% when benzene-hexane is used in the washing step and about 80% when cyclohexane-ethylene dichloride-ethyl ether is used.

High Pressure Liquid Chromatographic Determination of Chlorophacinone in Formulations

1979 ◽  
Vol 62 (5) ◽  
pp. 1001-1003
Author(s):  
Ralph G Grant ◽  
Richard K Pike
Keyword(s):  
High Pressure ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Whole Grain ◽  
High Pressure Liquid Chromatographic ◽  
Liquid Chromatograph ◽  
High Pressure Liquid Chromatograph ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A simple and rapid method is described determining for 2- ((p-chlorophenyl) phenylacetyl-1,3- indandione (chlorophacinone) in rodenticides formulated as tracking powders and whole grain and crushed grain baits. The bait is extracted with methanol containing an internal standard, and the extract is injected into a high pressure liquid chromatograph. The sample is analyzed by reverse phase chromatography on octadecyl (C18) bonded to glass beads with a mobile phase of methanolwater (35+65) plus 0.75% NH4OH. A 5 μL injection containing 240 ng benzophenone internal standard and 77 ng chlorophacinone produces half scale peaks at 280 nm with a full scale absorbance of 0.01 absorbance unit. Two formulations and a spiked sample were analyzed by the method. Recovery as determined by peak area was >97%.

Application of Gel Permeation Chromatography and Nonaqueous Reverse Phase Chromatography to High Pressure Liquid Chromatographic Determination of Retinyl Palmitate in Fortified Breakfast Cereals

1980 ◽  
Vol 63 (1) ◽  
pp. 131-136 ◽  
Author(s):  
William O Landen
Keyword(s):  
High Pressure ◽  
Vitamin A ◽  
Methylene Chloride ◽  
Colorimetric Method ◽  
Gel Permeation Chromatography ◽  
Retinyl Palmitate ◽  
Reverse Phase ◽  
High Pressure Liquid Chromatographic ◽  
Gel Permeation ◽  
Liquid Chromatographic

Abstract A high pressure liquid chromatographic (HPLC) method was developed for determining retinyl palmitate in cereals. Retinyl palmitate is fractionated from other methylene chloride-soluble components by using high pressure gel permeation chromatography (HP-GPC) followed by quantitation with nonaqueous reverse phase HPLC (RPHPLC). HP-GPC fractionation was accomplished using 2 µStyragel (100Å) columns connected in series on sample extracts in methylene chloride with methylene chloride as the mobile phase. A valve designed to facilitate the collection of the vitamin A fraction was installed in-line between the refractive index and absorbance detectors. RPHPLC quantitation was achieved on µBondapak C18 (10 µm) using methylene chloride–acetonitrile (30+70). Based on 23 repetitive analyses, recovery of vitamin A as retinyl palmitate in cereal products was 95.4±4.2% with spiking levels between 21.4 and 140 µg/g. Vitamin A in 15 cereals, representing bran, corn, oats, rice, and wheat, ranged from 34 to 194% of the declared level. The HPLC procedure was compared with the AOAC official colorimetric method and with an ultraviolet spectrophotometric method.

High Pressure Liquid Chromatographic Determination of Sulfanitran and Dinsed in Medicated Feeds and Premixes

1977 ◽  
Vol 60 (5) ◽  
pp. 1064-1066
Author(s):  
Kathleen L Eaves ◽  
Billy M Colvin ◽  
Alan R Hanks ◽  
Rodney J Bushway
Keyword(s):  
High Pressure ◽  
Colorimetric Method ◽  
Chromatographic Determination ◽  
High Pressure Liquid Chromatographic ◽  
Liquid Chromatograph ◽  
Ultraviolet Detector ◽  
Liquid Chromatographic Method ◽  
Medium Porosity ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A simple reverse phase high pressure liquid chromatographic method is described for determining sulfanitran (acetyl-p-nitrophenylsulfanilamide) and Dinsed (dinitrodiphenylsulfonylethylenediamine) in a variety of feed premixes and formulations. Feed premixes are extracted with dimethylformamide, and formulated feeds are extracted with hot methanol. The extract is filtered through medium porosity paper and injected into a liquid chromatograph equipped with a 254 nm ultraviolet detector and a 30 cm column packed with μBondapak C18. The mobile phase is acetonitrile-water (45+55) at a flow rate of 1.0 ml/min. Chromatography was complete in 10 min and peak heights were used for quantitation. Comparison of analyses of commercial samples by this method and by the AOAC colorimetric method, 42.176–42.179, showed close agreement. Recovery of spiked feed samples ranged from 98 to 105%. Butynorate and roxarsone, 2 other drugs which are normally found in combination with sulfanitran and Dinsed, do not interfere.

High Pressure Liquid Chromatographic Determination of Nitrofurazone in Milk

1979 ◽  
Vol 62 (1) ◽  
pp. 19-22 ◽  
Author(s):  
Arnost B Vilim ◽  
Agnes I Macintosh
Keyword(s):  
High Pressure ◽  
Screening Method ◽  
Chromatographic Determination ◽  
Organic Layer ◽  
High Pressure Liquid Chromatographic ◽  
Liquid Chromatograph ◽  
Milk Serum ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A rapid high pressure liquid chromatographic (HPLC) screening method for the quantitative determination of nitrofurazone in milk has been developed. The drug is extracted with ethyl acetate from a 2.0 ml milk serum sample, the organic layer is evaporated to dryness, and the residue is dissolved in the mobile phase and injected into the liquid chromatograph. A reverse phase μBondapak C18 column is used with monitoring at 365 nm. The detection limit is 5 ppb and recoveries are 57—67%. Mass spectroscopic confirmation of the HPLC nitrofuran peak is described.

Improved Method for High Pressure Liquid Chromatographic Determination of Chlorophacinone in Mouse Tissue

1982 ◽  
Vol 65 (6) ◽  
pp. 1299-1301
Author(s):  
Joseph B Addison
Keyword(s):  
High Pressure ◽  
Chromatographic Determination ◽  
Peak Height ◽  
Mouse Tissue ◽  
Height Measurement ◽  
Liquid Chromatograph ◽  
Order Of Magnitude ◽  
High Pressure Liquid Chromatograph ◽  
Liquid Chromatographic

Abstract A simplified method is described for the determination of chlorophacinone, 2-[(p-chlorophenyl)- phenylacetyl]-l,3-indandione, in homogenized mice. Chlorophacinone is extracted with acetonitrile. After Florisil cleanup, the extract is injected into a high pressure liquid chromatograph for reverse phase chromatography on a polar Lichrosorb NH2 (10 μm) column, with a mobile phase of acetonitrile-water (80 + 20). An injection containing 70 ng chlorophacinone produces 1/2 scale peaks at 254 nm with a full scale absorbance of 0.1 unit, an order of magnitude improvement over the sensitivity reported earlier with a 280 nm detector. Six homogenized mice samples and six spiked homogenized mice samples were quantitatively analyzed for trace levels of chlorophacinone by this method. Recoveries from spiked samples, as determined by peak height measurement, were >95%. Mean retention time for the chlorophacinone peaks in all samples was 6.05 ± 0.05 min. Chlorophacinone levels determined in homogenized whole mouse samples ranged from 0 to 63 ppm.

Automated High Pressure Liquid Chromatographic System for Determination of Mannitol, Sorbitol, and Xylitol in Chewing Gums and Confections

1982 ◽  
Vol 65 (1) ◽  
pp. 76-78
Author(s):  
Eugene C Samarco ◽  
Ernest S Parente
Keyword(s):  
High Pressure ◽  
Standard Addition ◽  
High Pressure Liquid Chromatographic ◽  
Liquid Chromatograph ◽  
Liquid Chromatographic Method ◽  
Chewing Gums ◽  
Confectionery Products ◽  
Cation Exchange Column ◽  
Liquid Chromatographic

Abstract A rapid, precise, and reproducible automated high pressure liquid chromatographic method was developed to determine xylitol in the presence of mannitol and sorbitol in chewing gums and confectionery products. A mobile phase of water and methanol elutes the polyols simultaneously from a cation-exchange column without pretreatment or derivatization. Injections into the liquid chromatograph were made by an autosampler, and data reduction was performed with a programmable electronic integrator. Average recoveries for one level each of mannitol, sorbitol, and xylitol in 6 replicate samples prepared by the standard addition technique were 102.5,100.5, and 100.7%, respectively.

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