Liquid Chromatographic Determination of Bentazon in Technical and Formulated Products: Collaborative Study

1994 ◽  
Vol 77 (2) ◽  
pp. 328-330
Author(s):  
Thomas M Schmitt
Keyword(s):  
Collaborative Study ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Relative Standard ◽  
Before And After ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
The Mean ◽  
Liquid Chromatographic

Abstract An isocratic reversed-phase liquid chromatographic (LC) procedure for measuring bentazon in commercial herbicide products and aqueous formulations was collaboratively studied by 16 laboratories. Samples are dissolved in LC eluent [0.075M sodium acetate–methanol (60 + 40)] and analyzed by LC on a 30 cm × 3.9 mm octadecylsilyl column with detection by UV absorbance at 340 nm. The quantity of active ingredient is determined by comparing the mean response factor (RF) of the sample to the mean RF of standards injected just before and after each pair of sample injections. The average relative standard deviation (RSDR) for 3 formulations studied was 1.54%; the RSDR for a technical sample was 0.77%. The method has been adopted first action by AOAC INTERNATIONAL.

scholarly journals Liquid Chromatographic Determination of the Glycoalkaloids α-Solanine and α-Chaconine in Potato Tubers: NMKL Interlaboratory Study

1997 ◽  
Vol 80 (3) ◽  
pp. 549-554 ◽  
Author(s):  
Karl-Erik Hellenás ◽  
Carina Branzell ◽  
H Poutanen ◽  
T Suortti ◽  
R Kaario ◽  
...  
Keyword(s):  
Collaborative Study ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Potato Tubers ◽  
Photometric Detection ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract Twelve laboratories participated in a collaborative study to evaluate precision parameters of a liquid chromatographic method for analysis of the glycoalkaloids α-solanine and α-chaconine in potato tubers. Samples consisted of frozen potato tuber homogenates distributed as 3 blind duplicates and 3 split-level pairs. The analytical method included aqueous extraction, workup on disposable solidphase extraction cartridges, and reversed-phase chromatography with photometric detection at 202 nm. Results for α-solanine and α-chaconine were received from 10 and 9 laboratories, respectively. Relative standard deviations for reproducibilo ity for α-solanine and α-chaconine were similar, ranging from 8 to 13% in the applied concentration range of 12 to 260 mg/kg fresh weight.

Liquid Chromatographic Determination of 2-Chloro-4-nitroaniline, 2-Naphthol, and 2,4-Dinitroaniline in D&C Red No. 36

1993 ◽  
Vol 76 (2) ◽  
pp. 287-291 ◽  
Author(s):  
Alan L Scher ◽  
Nicholas C Adamo
Keyword(s):  
Chromatographic Determination ◽  
Reversed Phase ◽  
Calibration Data ◽  
Reversed Phase Liquid Chromatography ◽  
Relative Standard ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic ◽  
Cellulose Column

Abstract A method is described for the determination of the intermediates and a related impurity in D&C Red No. 36 by reversed-phase liquid chromatography. This method may be used to ensure that limits set forth in the Code of Federal Regulations on the amounts of these 3 impurities in the color are not exceeded. The pigment is dissolved in boiling dioxane and then precipitated. The filtrate is chromatographed by isocratic elution, and then the column is washed and reequilibrated. Impurities were identified as 2-chloro-4-nitroaniline (2-CI-4-NA), 2-naphthol, and 2,4-dinitroaniline (2,4-DNA) by comparison of their retention times and spectra with those of standards. Peak area calibrations were linear to at least 0.375% 2-CI-4-NA, 1.25% 2-naphthol, and 0.025% 2,4-DNA, all with zero intercepts. At the specification levels, 99% confidence limits were 0.30 ± 0.006% for 2-CI-4-NA, 1.0 ± 0.03% for 2-naphthol, and 0.020 ± 0.0004% for 2,4-DNA. The limits of determination calculated from calibration data were 0.019% for 2-CI-4-NA, 0.10% for 2-naphthol, and 0.0014% for 2,4-DNA at the 99% confidence level. Recoveries were 100-104% for 2-CI-4-NA added to purified D&C Red No. 36,100% for 2-naphthol, and 100-110% for 2,4-DNA; relative standard deviations were 0.8-3.4%. A survey of certified D&C Red No. 36 samples showed that the batches contained higher levels of intermediates than were determined previously by a cellulose column method in which the pigment was not dissolved.

Continuous Flow and Liquid Chromatographic Determination of p-Toluenesulfonamide in Ice Cream: Interlaboratory Study

1993 ◽  
Vol 76 (3) ◽  
pp. 570-574 ◽  
Author(s):  
Paul R Beljaars ◽  
Remmelt Van Dijk ◽  
Arie Brands ◽  
◽  
M Anderegg ◽  
...  
Keyword(s):  
Continuous Flow ◽  
Collaborative Study ◽  
Ice Cream ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Relative Standard ◽  
Liquid Chromatographic Determination ◽  
Standard Deviations ◽  
Liquid Chromatographic

Abstract A collaborative study of the continuous flow (CF) and liquid chromatographic determination of p-toluenesulfonamide (p-TSA) in ice cream was conducted by the Project Group on Collaborative Studies (PCS) of the Inspectorate for Health Protection, Food Inspection Service, The Netherlands. The procedure involves extraction of samples with water followed by cleanup of the extracts by dialysis in the CF system. Dialysates are injected by using a loop injector (500 μL) on a reversed-phase octadecylsilane bonded-phase (C18) column, chromatographed with methanol-water (25 + 75, v/v) as mobile phase, and quantitated by fluorescence detection at 230 nm (excitation) and 295 nm (emission). Seven ice-cream samples containing 0-6.35 mg/kg p-TSA at 4 different levels (1 blank and 3 pairs of split-level samples) were singularly analyzed according to the proposed procedure by 11 laboratories. The data were analyzed by the International Union of Pure and Applied Chemistry/ International Organization for Standardization/ AOAC protocol for statistics. No Cochran and Grubbs outliers were found among the participants. For all samples analyzed, repeatability relative standard deviations (RSDr) varied from 2.08 to 3.67%, whereas the reproducibility relative standard deviations (RSDR) ranged from 7.79 to 11.68%. The average p-TSA values for the split levels 1,2, and 3 were 0.55, 1.02, and 4.44 mg p-TSA/kg, respectively, with mean recoveries ranging from 76 to 79% (overall recovery range for all levels, 63-101%). No false-positive results were reported for the blank sample, and no interference was encountered by the presence of vanilla in samples.

scholarly journals Liquid Chromatographic Determination of 4, 4' -Dinitrocarbanilide, the Active Component of the Infertility Agent Nicarbazin, in Chicken, Duck, Goose, and Snake Eggs

2003 ◽  
Vol 86 (6) ◽  
pp. 1144-1148
Author(s):  
Thomas M Primus ◽  
Dennis J Kohler ◽  
Margaret A Goodall ◽  
Christi Yoder ◽  
Thomas Mathies ◽  
...  
Keyword(s):  
Active Component ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Reversed Phase Liquid Chromatography ◽  
Ultraviolet Absorbance ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
The Mean ◽  
Liquid Chromatographic

Abstract 4, 4'-Dinitrocarbanilide (DNC) was extracted from chicken, duck, goose, and snake eggs and isolated by reversed-phase liquid chromatography. DNC was detected by ultraviolet absorbance at 347 nm and quantitated by comparison with a calibration standard. Recoveries of DNC from fortified control chicken, duck, goose, and snake egg samples were determined for DNC levels of 0.16, 10, and 16 μg/g. The mean recoveries from chicken, duck, goose, and snake eggs were 92 ± 4, 88 ± 9, 87 ± 7, and 95 ± 6%, respectively. The method limits of detection for DNC in chicken, duck, goose, and snake eggs ranged from 0.015 to 0.035 μg/g. The reported method is much simpler than and equally efficient as previous methods developed for the determination of DNC residues in egg contents.

Liquid Chromatographic Determination of Phosphamidon in Technical and Formulated Products: CIPAC Collaborative Study

1994 ◽  
Vol 77 (1) ◽  
pp. 8-10
Author(s):  
Alan R Hanks
Keyword(s):  
Collaborative Study ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Reversed Phase Liquid Chromatography ◽  
Buffer Solution ◽  
External Standard ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract Phosphamidon is determined by reversed-phase liquid chromatography on a C18 column with a mobile phase of acetonitrile—methanol buffer solution, detected by a UV absorbance detector set at 218 nm, and quantitated by area measurements using an external standard. The method was adopted first action by AOAC INTERNATIONAL.

Liquid Chromatographic Determination of Glyphosate and Aminomethylphosphonic Acid (AMPA) in Environmental Water: Collaborative Study

1991 ◽  
Vol 74 (2) ◽  
pp. 317-323 ◽  
Author(s):  
Mark E Oppenhuizen ◽  
John E Cowell
Keyword(s):  
Collaborative Study ◽  
Chromatographic Determination ◽  
Environmental Water ◽  
Aminomethylphosphonic Acid ◽  
Relative Standard ◽  
Total Variability ◽  
Liquid Chromatographic Determination ◽  
Predicted Values ◽  
Liquid Chromatographic

Abstract A new method for determination of glyphosate and amlnomethylphosphonlc acid (AMPA) residues In environmental water was collaboratively studied by 6 laboratories. The method Is simpler and shorter than previous methods. A filtered volume of water is evaporated to dryness and the residue Is dissolved In a buffered EDTA solution. Glyphosate and AMPA are determined by liquid chromatography with postcolumn reaction detection. The method was validated over the range 0.50-5000 ppb, although one of the collaborating laboratories could not reliably quantltate below 1.0 ppb. Statistical analysis of the results showed that typical reproducibility relative standard deviations (RSDR) ranged from 11 to 20% for both glyphosate and AMPA, which compares very well with predicted values for this concentration range. Total variability (as measured by sR) Increased with increasing fortification level. The method has been adopted official first action by AOAC.

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.

Simultaneous Liquid Chromatographic Determination of Thiamine and Riboflavin in Selected Foods

1993 ◽  
Vol 76 (5) ◽  
pp. 1156-1160 ◽  
Author(s):  
Art Sims ◽  
Dirk Shoemaker
Keyword(s):  
American Association ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Fluorescence Detector ◽  
Liquid Chromatographic Determination ◽  
Optimum Wavelength ◽  
The Mean ◽  
Sensitivity Data ◽  
Liquid Chromatographic

Abstract A reliable, improved liquid chromatographic (LC) method has been developed for the measurement of thiamine and riboflavin in foods. The major improvement in the method is the chromatographic separation achieved. The method is also very reproducible and extremely sensitive. After autoclave extraction, samples are derivatized to form thiochrome (a highly fluorescent oxidation product of thiamine). Riboflavin is naturally fluorescent. Interferences are removed on a Ci8 cartridge and chromatographed by using a reversed-phase separation. The mobile phase used is 72% 0.005M NH4OAc (pH 5.0)-28% MeOH. Fluorescence detection using wavelength switching, 370-435 for thiamine and 370-520 for riboflavin, allows determination of each vitamin at its optimum wavelength for maximum sensitivity. Detection limits were 0.05 ng for both thiamine and riboflavin. The method can also be performed by using a fluorescence detector at a single wavelength, but with a sacrifice of sensitivity. Data comparisons between AOAC fluorometric and LC results were excellent for routine samples, as well as for American Association of Cereal Chemists (AACC) check samples. All LC results from AACC samples were within 2 standard deviations of the mean. Reproducibility was 1.9% for thiamine and 1.6% for riboflavin.

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.

Liquid Chromatographic Determination of Thiamine in Rodent Feed by Postcolumn Derivatization and Fluorescence Detection

1995 ◽  
Vol 78 (2) ◽  
pp. 307-309 ◽  
Author(s):  
Theresa A Gehring ◽  
Willie M Cooper ◽  
Claude L Holder ◽  
Harold C Thompson
Keyword(s):  
Chromatographic Determination ◽  
Reversed Phase ◽  
Detector Response ◽  
Fluorescence Excitation ◽  
Liquid Chromatographic Method ◽  
Essential Nutrient ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method was developed for determination of the essential nutrient thiamine (vitamin Bi) in rodent feed. Thiamine was extracted with hydrochloric acid, separated by reversed-phase liquid chromatography, derivatized postcolumn to thiochrome with potassium hydroxide and potassium ferricyanide, and detected by fluorescence. Excitation and emission wavelengths were 370 and 430 nm, respectively. Detector response was linear in the range of 2.58 to 15.5 ng of thiamine injected. Instrument detection limit was 5 pg of thiamine injected.

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