High-Performance Liquid Chromatographic Determination of L-Aspartyl-L-Phenylalanine Methyl Ester in Various Food Products and Formulations

1976 ◽  
Vol 59 (5) ◽  
pp. 1048-1050
Author(s):  
Lew Fox ◽  
Gaylord D Anthony ◽  
Edward P K Lau
Keyword(s):  
Methyl Ester ◽  
High Performance ◽  
Food Products ◽  
Chromatographic Determination ◽  
High Performance Liquid Chromatographic ◽  
Coefficients Of Variation ◽  
Wide Range ◽  
Cation Exchange Column ◽  
Liquid Chromatographic ◽  
Phenylalanine Methyl Ester

Abstract A simple, rapid, and specific high-performance liquid chromatographic (HPLC) procedure is described for the analysis of the chemical sweetener L-aspartyl-L-phenylalanine methyl ester (aspartame). Using a strong cation exchange column and pressures <1000 psig, an analysis can be performed in <15 min. The technique has been applied to a wide range of food products and formulations. No interferences were found in the samples studied. Recoveries are quantitative, and the coefficients of variation for replicate analyses are ≤2.5%.

High Performance Liquid Chromatographic Determination of Carbaryl Insecticide in Formulations

1980 ◽  
Vol 63 (3) ◽  
pp. 650-652
Author(s):  
William H Mcdermott
Keyword(s):  
High Performance ◽  
Methylene Chloride ◽  
Collaborative Study ◽  
Chromatographic Determination ◽  
High Performance Liquid Chromatographic ◽  
Modified Silica Gel ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A high performance liquid chromatographic method for carbaryl in formulations has been developed and used to assay 3 formulations in a 10-day repeatability study. The method uses a cyano modified silica gel column packing and a mobile phase of heptane-methylene chloride-isopropanol-methanol (60+35+4.8+0.2). The coefficients of variation for 2 wettable powders and one aqueous flowable formulation were 0.61, 0.62, and 0.75%, respectively. It is recommended that a collaborative study be conducted on this method.

High Performance Liquid Chromatographic Determination of Methapyrilene Hydrochloride in Feed and Sleep Aid Tablets

1981 ◽  
Vol 64 (4) ◽  
pp. 889-892
Author(s):  
Badaruddin Shaikh ◽  
Margarette R Hallmark
Keyword(s):  
High Performance ◽  
Ammonium Carbonate ◽  
Chromatographic Determination ◽  
High Performance Liquid Chromatographic ◽  
Reverse Phase ◽  
Phase Partition ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract Methapyrilene hydrochloride (MP·HCl) was extracted from feed with methanol and determined by reverse phase partition chromatography in less than 15 min, using isocratic elution with acetonitrile-1.1% ammonium carbonate (1 + 1) as the mobile phase. This procedure was tested on feed treated with MP·HCl at levels of 125,500, and 2000 ppm. Recoveries were 104,95, and 96% with coefficients of variation of 2.4,1.6, and 0.6%, respectively. MP·HCl in feed was stable for 14 days. This method was also successfully used to determine MP·HCl in 3 sleep aid tablets.

Liquid-chromatographic determination of norepinephrine and epinephrine in human plasma.

1980 ◽  
Vol 26 (2) ◽  
pp. 194-196
Author(s):  
Y Yui ◽  
T Fujita ◽  
T Yamamoto ◽  
Y Itokawa ◽  
C Kawai
Keyword(s):  
Human Plasma ◽  
High Performance ◽  
Chromatographic Determination ◽  
High Performance Liquid Chromatographic ◽  
Peak Height ◽  
Sodium Phosphate Buffer ◽  
Cation Exchange Column ◽  
Normal Human ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract We describe a “high-performance” liquid-chromatographic method for measuring picogram amounts of norepinephrine and epinephrine simultaneously in human plasma. Alumina-treated samples are injected onto a strong cation-exchange column (Zipax SCX) for the separation of catecholamines, with a sodium phosphate buffer/acetonitrile mixture as mobile phase. The separated catecholamines then enter a continuous-flow system and the reagents for the trihydroxyindole reaction are added sequentially; the fluorescent products are then measured with a spectrofluorophotometer. Analytical recoveries from plasma averaged 66% for norepinephrine, 68% for epinephrine. Amount and response (peak height) were linearly related up to 1000 pg. For catecholamines in human plasma, within-run and day-to-day CV's were 0.2% and 1.0%, respectively, for norepinephrine, and 0.3% and 0.9%, respectively, for epinephrine. Average values for norepinephrine and epinephrine in apparently normal human plasma were 185 +/- 29 ng/L and 32 +/- 8 ng/L, respectively (mean +/- SEM, n = 10). This relatively rapid and highly sensitive system is suitable for routine use.

High Performance Liquid Chromatographic Determination of α-Tocopherol in Fish Liver

1980 ◽  
Vol 63 (4) ◽  
pp. 889-893 ◽  
Author(s):  
Silas S O Hung ◽  
Young C Cho ◽  
Stanley J Slinger
Keyword(s):  
High Performance ◽  
Chromatographic Determination ◽  
High Performance Liquid Chromatographic ◽  
Peak Height ◽  
Fish Liver ◽  
Liver Sample ◽  
Liquid Chromatograph ◽  
Simple Method ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic

Abstract A simple method is described for the determinatio n of α-tocopherol in fish liver by high performance liquid chromatography. This method does not involve saponification or thin layer chromatography and thus avoids the destruction of α-tocopherol during sample preparation. The homogenized liver sample is extracted twice with dioxane–isooctane (20+80, v/v), and the combined extracts are dried under vacuum. The residue is extracted 3 times with acetonitrile from which α-tocopherol is then extracted with isooctane. The residue from the dried isooctane solution is dissolved in methanol–water (90+10, v/v) which is injected directly onto a micro Bondapak C18 high performance liquid chromatograph. The detection response to α-tocopherol at 280 nm was measured by peak height which was linear from 1 to 10 μg/25 μL injection. The coefficients of variation for retention time and peak height for 5 replicate analyses of the standard during 2 weeks were 1.4 and 2.4%, respectively. Recovery of α-tocopherol added to the sample before homogenization was 80–92% with a mean of 86.2% and a coefficient of variation of 4.9%. The minimum amount of sample and the concentration of α-tocopherol that can be accurately determined by the method are 0.5 g liver and 1 μg α-tocopherol/g liver, respectively.

Liquid-chromatographic determination of norepinephrine and epinephrine in human plasma.

1980 ◽  
Vol 26 (2) ◽  
pp. 194-196 ◽  
Author(s):  
Y Yui ◽  
T Fujita ◽  
T Yamamoto ◽  
Y Itokawa ◽  
C Kawai
Keyword(s):  
Human Plasma ◽  
High Performance ◽  
Chromatographic Determination ◽  
High Performance Liquid Chromatographic ◽  
Peak Height ◽  
Sodium Phosphate Buffer ◽  
Cation Exchange Column ◽  
Normal Human ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract We describe a “high-performance” liquid-chromatographic method for measuring picogram amounts of norepinephrine and epinephrine simultaneously in human plasma. Alumina-treated samples are injected onto a strong cation-exchange column (Zipax SCX) for the separation of catecholamines, with a sodium phosphate buffer/acetonitrile mixture as mobile phase. The separated catecholamines then enter a continuous-flow system and the reagents for the trihydroxyindole reaction are added sequentially; the fluorescent products are then measured with a spectrofluorophotometer. Analytical recoveries from plasma averaged 66% for norepinephrine, 68% for epinephrine. Amount and response (peak height) were linearly related up to 1000 pg. For catecholamines in human plasma, within-run and day-to-day CV's were 0.2% and 1.0%, respectively, for norepinephrine, and 0.3% and 0.9%, respectively, for epinephrine. Average values for norepinephrine and epinephrine in apparently normal human plasma were 185 +/- 29 ng/L and 32 +/- 8 ng/L, respectively (mean +/- SEM, n = 10). This relatively rapid and highly sensitive system is suitable for routine use.

High Performance Liquid Chromatographic Determination of Lactose in Milk

1981 ◽  
Vol 64 (4) ◽  
pp. 805-807
Author(s):  
Leslie G West ◽  
Marie A Llorente
Keyword(s):  
High Performance ◽  
Chromatographic Determination ◽  
High Performance Liquid Chromatographic ◽  
Chocolate Milk ◽  
Silica Column ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A rapid and simple high performance liquid chromatographic method for the determination of lactose in milk was developed. Samples were diluted with 0.5% perchloric acid and centrifuged, and an aliquot of the supernate was mixed with acetonitrile. Lactose was separated on a 10 μm particle-size silica column with aqueous acetonitrile as the mobile phase. The recovery of lactose from whole, skim, and chocolate milk averaged 99.2, 101.1, and 100.4%, respectively. Coefficients of variation for routinely performed duplicate determinations are between 1.0 and 1.5%.

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