Liquid Chromatographic Determination of Residual Styrene in Polystyrene Food Packaging

1981 ◽  
Vol 64 (3) ◽  
pp. 647-652
Author(s):  
Sandra L Varner ◽  
Charles V Breder
Keyword(s):  
Mobile Phase ◽  
Food Packaging ◽  
Chromatographic Determination ◽  
Reverse Phase ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic ◽  
Plastic Containers

Abstract The determination of residual styrene in polystyrene food packaging polymers by a reverse phase liquid chromatographic method is described. The polymer is dissolved in tetrahydrofuran and then reprecipitated with methanol. The filtered solution is chromatographed by using an aqueous tetrahydrofuran mobile phase, and the styrene is detected and quantitated by ultraviolet at 254 nm. The detection limit for the method is about 0.5 ppm styrene on a solution basis and 20 ppm in the polymer. The average recovery of styrene from spiked polymer (about 50–3700 ppm) is 88%. Apparent residual styrene was determined in several commercial products, including rigid polystyrene cups, flexible plastic containers, and several foam products. The monomer levels ranged from about 60 to 2250 ppm.

Liquid Chromatographic Determination of Carminic Acid in Yogurt

1989 ◽  
Vol 72 (2) ◽  
pp. 231-234 ◽  
Author(s):  
Mercedes Jalón ◽  
Majesús Peńa ◽  
Julián C Rivas
Keyword(s):  
Chromatographic Determination ◽  
Carminic Acid ◽  
Reverse Phase ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
Array Detection ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract A reverse-phase liquid chromatographic method is described for the determination of carminic acid in yogurt. A C18 column is used with acetonitrile-1.19M formic acid (19 + 81) as mobile phase and diode array detection. Sample preparation includes deproteinization with papain and purification in a polyamide column. The relative standard deviation for repeated determinations of carminic acid in a commercial strawberry-flavored yogurt was 3.0%. Recoveries of carminic acid added to a natural-flavored yogurt ranged from 87.2 to 95.3% with a mean of 90.2%. The method permits measurement of amounts as low as 0.10 mg/kg.

Reverse-Phase Liquid Chromatographic Determination of Paraquat and Diquat in Agricultural Products

1987 ◽  
Vol 70 (6) ◽  
pp. 1008-1011 ◽  
Author(s):  
Toshihiro Nagayama ◽  
Toshio Maki ◽  
Kimiko Kan ◽  
Mami Iida ◽  
Taichiro Nishima
Keyword(s):  
Chromatographic Determination ◽  
Agricultural Products ◽  
Minimum Detectable Concentration ◽  
Reverse Phase ◽  
Liquid Chromatographic Method ◽  
Detectable Concentration ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract A simple, rapid, highly sensitive liquid chromatographic method is described for the quantitative determination of paraquat and diquat residues in agricultural products. Paraquat and diquat are extracted with hot dilute hydrochloric acid and are cleaned up on an Amberlite CG-50 column, followed by reverse-phase liquid chromatography on an NH, column, with ultraviolet detection at 257 nm (paraquat) and 310 nm (diquat). The minimum detectable concentration of both paraquat and diquat was 0.5 ng per injection, which corresponds to a lower detection limit of approximately 0.02 fjg/g in the original samples. Recoveries of paraquat and diquat added to various samples were greater than 79%, and averaged 91 and 90%, respectively, at the 0.1 and 1.0 μg/g spiking levels.

Reverse Phase Liquid Chromatographic Determination of Edifenphos in Technical and Emulsifiable Concentrate Formulations

1985 ◽  
Vol 68 (1) ◽  
pp. 138-140
Author(s):  
Rajesh Khazanchi ◽  
Nripendra K Roy
Keyword(s):  
Chromatographic Determination ◽  
Reference Standard ◽  
Preparative Liquid Chromatography ◽  
Reverse Phase ◽  
Emulsifiable Concentrate ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract A convenient reverse phase liquid chromatographic method has been developed for determination of edifenphos in its technical product and emulsifiable concentrate. The method allows determination of the active ingredient of the formulation directly, without any solvent extraction. In addition, reference standard edifenphos has been obtained by preparative liquid chromatography.

Liquid Chromatographic Determination of Methyldopa and Methyldopa-Thiazide Combinations in Tablets: Collaborative Study

1984 ◽  
Vol 67 (6) ◽  
pp. 1118-1120
Author(s):  
Ting Susan ◽  
◽  
R L Brown ◽  
L A Dougherty ◽  
J B Schepman ◽  
...  
Keyword(s):  
Chromatographic Method ◽  
Collaborative Study ◽  
Chromatographic Determination ◽  
Reverse Phase ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Repeatability And Reproducibility ◽  
Liquid Chromatographic

Abstract A reverse phase liquid chromatographic method for the determination of methyldopa, methyldopa-hydrochlorothiazide, and methyldopachlorothiazide in tablets was collaboratively studied by 8 laboratories. Each collaborator received 20 samples that included drug substance, synthetic and commercial tablet compositions. The overall repeatability and reproducibility standard deviations for commercial tablets were 1.11 and 1.75% for methyldopa, 0.96 and 1.62% for chlorothiazide, and 1.21 and 2.15% for hydrochlorothiazide, respectively. The overall recoveries of methyldopa, chlorothiazide, and hydrochlorothiazide added to synthetic tablets were 100.78, 100.70, and 101.34%, respectively. The method has been adopted official first action.

Liquid Chromatographic Determination of Major Alkaloids in Gum Opium

1985 ◽  
Vol 68 (4) ◽  
pp. 801-803
Author(s):  
Vinod K Srivastava ◽  
Mohan L Maheshwari
Keyword(s):  
Mobile Phase ◽  
Sodium Acetate ◽  
Chromatographic Determination ◽  
Aqueous Acetic Acid ◽  
Reverse Phase ◽  
Qualitative And Quantitative ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract An isocratic reverse phase liquid chromatographic (LC) system has been developed for qualitative and quantitative assay of morphine, codeine, thebaine, papaverine, and narcotine in gum opium. Five extractions with 2.5% aqueous acetic acid quantitatively extracted the major alkaloids. A mixture of 1% aqueous sodium acetate (pH 6.78), acetonitrile, and 1,4-dioxane (75 + 20 + 5) is used as LC mobile phase | for better resolution of alkaloid peaks, especially those of morphine and codeine. The method is suitable for routine analysis of gum opium I samples.

Simultaneous Liquid Chromatographic Determination of Some Tetracyclines in Serum

1986 ◽  
Vol 69 (5) ◽  
pp. 760-762
Author(s):  
Krystyna Tyczkowska ◽  
Arthur L Aronson
Keyword(s):  
Molecular Weight ◽  
Mobile Phase ◽  
Chromatographic Determination ◽  
Molecular Weight Cutoff ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract A sensitive liquid chromatographic method has been developed for the simultaneous determination of oxytetracycline, minocycline, tetracycline, and doxycycline in serum. A serum sample is vortex-mixed with a solution of mobile phase for tetracyclines and 2% (v/v) phosphoric acid. The mixture is filtered using a 30 000 molecular weight cutoff microseparation tube which separates high-molecular-weight solutes following low-speed centrifugation. Tetracyclines are separated from other serum components by reverse phase liquid chromatography (LC) with buffered methanol mobile phase. Ultraviolet absorbance of the column effluent is monitored at 267 nm. Concentrations as low as 0.2 μg/mL of tetracyclines in serum are quantitatable, with recoveries from 76.2 to 102.6% and coefficients of variation from 2.69 to 5.36%. The method has been tested in bovine, porcine, equine, caprine, ovine, canine, feline, and avian (turkey) serum.

Reverse Phase Liquid Chromatographic Determination of Aspartame in Beverages and Beverage Mixes

1984 ◽  
Vol 67 (3) ◽  
pp. 510-513 ◽  
Author(s):  
Norma G Webb ◽  
Darrell D Beckman
Keyword(s):  
Mobile Phase ◽  
Isopropyl Alcohol ◽  
Chromatographic Determination ◽  
Artificial Sweetener ◽  
Reverse Phase ◽  
Acetic Acid Water ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract A method is described for determining the artificial sweetener aspartame in beverages and beverage mixes by liquid chromatography. Aspartame is separated on a μC18 column, using a mobile phase of acetic acid, water, and isopropyl alcohol at pH 3.0 and UV detection at 254 nm. Beverages are filtered through 0.45 μm filters and injected directly into the chromatograph. Aspartame is eluted in approximately 7 min. Detection of aspartame is confirmed by a UV scan of the trapped peak. Aspartame is quantitated in the presence of other beverage additives such as saccharin, caffeine, sodium benzoate, artificial colors, and artificial flavors. Results are presented for spiked soda beverages, beverages from fruit-flavored mixes, instant tea, reconstituted presweetened drink mixes, and a powdered tabletop sweetener.

Liquid Chromatographic Determination of Levodopa, Levodopa-Carbidopa, and Related Impurities in Solid Dosage Forms

1986 ◽  
Vol 69 (1) ◽  
pp. 169-173 ◽  
Author(s):  
Susan Ting
Keyword(s):  
Chromatographic Determination ◽  
Dosage Forms ◽  
Solid Dosage Forms ◽  
Reverse Phase ◽  
Solid Dosage ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract A rapid reverse phase liquid chromatographic method was developed for the determination of levodopa and levodopa-carbidopa in tablets and capsules. The method also separates these drugs from 3-(3,4,6- trihydroxyphenyl)alanine and methoxytyrosine, impurities of levodopa, and from methyldopa and 3-O-methylcarbidopa, impurities of carbidopa. The mobile phase was 3% acetic acid and the detection wavelength was 280 nm. The method was linear over the concentration range 0.05-0.40 mg levodopa/mL, 0.01-0.06 mg carbidopa/mL, 0.9- 12.8 μg 3-(3,4,6-trihydroxyphenyl)alanine/mL, 0.7-3.1 μg methyldopa/ mL, 5-20 μg methoxytyrosine/mL, and 0.5-3.3 μg 3-O-methylcarbidopa/ mL. Mean recoveries (%) for spiked commercial tablets were: levodopa 100.3, carbidopa 100.4, 3-(3,4,6-trihydroxyphenyl) alanine 99.1, methoxytyrosine 100.0, methyldopa 100.0, and 3-O-methylcarbidopa 99.4.

Liquid Chromatographic Determination of Acetaminophen in Tablets: Collaborative Study

1987 ◽  
Vol 70 (2) ◽  
pp. 212-214
Author(s):  
David J Krieger
Keyword(s):  
Collaborative Study ◽  
Chromatographic Determination ◽  
Generic Product ◽  
Single Component ◽  
Reverse Phase ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract A reverse phase liquid chromatographic method previously reported for the determination of acetaminophen in tablets was collaboratively studied by 5 laboratories. Each collaborator received duplicate samples of a synthetic tablet formulation and 3 powdered commercial tablet composites. The composites represented single-component and multi-component proprietary products and a single-component generic product. The pooled repeatability (CVD„) and reproducibility (CVDJ values for the proprietary tablets were 0.89 and 1.34%, respectively. For the generic tablets, these values were 0.66 and 0.74%, respectively. The pooled recovery value for acetaminophen added to the synthetic formulation was 98.9 ± 0.7% (n = 10) with a CV of 0.75%, CVD„ of 0.37%, and CVD„ of 0.78%. The overall repeatability of the method was 0.64%, and the overall reproducibility was 0.95%. The method has been adopted official first action.

Liquid Chromatographic Determination of Nicarbazin in Feed

1985 ◽  
Vol 68 (3) ◽  
pp. 596-598 ◽  
Author(s):  
Jeffrey A Hurlbut ◽  
Cyril T Nightengale ◽  
Roger G Burkepile
Keyword(s):  
Mobile Phase ◽  
Chromatographic Determination ◽  
Feed Additives ◽  
Alumina Column ◽  
Reverse Phase ◽  
Ultraviolet Detection ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method was developed for the determination of nicarbazin (4,4'-dinitrocarbanilide.2-hydroxy-4,6-dimethylpyrimidine) in chicken feed. Ground feed was extracted with hot dimethylformamide, filtered, and then cleaned up on an alumina column. The nicarbazin was eluted from the column with ethanol and quantitated using a reverse phase C-18 column, with a methanol-water mobile phase and ultraviolet detection at 344 nm. Recoveries at a typical use level of 100 μg/g feed averaged 98% with a standard deviation of 3%. Samples fortified at levels as low as 0.1 μg/g were analyzed with 92% recovery. The detection limit is 1 ng, and the response is linear between 4 and 1000 ng. Feed additives in combination with nicarbazin do not interfere with recovery.

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