High Pressure Liquid Chromatographic Determination of Imazalil Residues in Gtrus Fruit

1978 ◽  
Vol 61 (6) ◽  
pp. 1469-1474
Author(s):  
Shirley M Norman ◽  
David C Fouse

Abstract A high pressure reverse phase liquid chromatographic method is described for determining the fungicide imazalil (1-[2,4-dichlorophenyl) -2- (2-propenyloxy)ethyl] -1H-imidazole) residues in whole citrus fruit, peel, and pulp. Imazalil is extracted from the fruit with ethyl acetate, partitioned into acid and back into ethyl acetate for cleanup, and detected by ultraviolet absorbance at 202 nm. Recovery from whole ground fruit of known amounts of imazalil applied to the surface of intact fruit averaged 84% 24 hr after application and 80% after the fruit had been stored 4 weeks at 15°C.

1989 ◽  
Vol 72 (2) ◽  
pp. 231-234 ◽  
Author(s):  
Mercedes Jalón ◽  
Majesús Peńa ◽  
Julián C Rivas

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.


1995 ◽  
Vol 78 (2) ◽  
pp. 307-309 ◽  
Author(s):  
Theresa A Gehring ◽  
Willie M Cooper ◽  
Claude L Holder ◽  
Harold C Thompson

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.


1981 ◽  
Vol 64 (6) ◽  
pp. 1411-1413
Author(s):  
William J Hurst ◽  
James M Mckim ◽  
Robert A Martin

Abstract A high pressure liquid chromatographic method is described for the determination of amaranth (FD&C Red No. 2; Red No. 2) in licorice products. The Red No. 2 is extracted with a basic buffer solution, cleaned up on a Sep-Pak column, chromatographed on a reverse phase column in the ion pairing mode, and detected at 254 nm. The procedure is time-conservative with accurate and precise results. Recovery data ranged from 93 to 104%, and coefficients of variation were less than 4% for standards and samples.


1984 ◽  
Vol 67 (2) ◽  
pp. 225-227 ◽  
Author(s):  
Richard L Everett ◽  
◽  
L Allgire ◽  
R J Ballbach ◽  
J Booth ◽  
...  

Abstract A reverse phase liquid chromatographic method was developed for determining methocarbamol in injection and tablet dosage forms. The injections require dilution only; the tablets require a nitration step before introduction into the chromatograph. Response for methocarbamol was linear over the range 0-18 μg, using an ultraviolet detector at 274 nm. Recoveries by the author ranged from 96.1 to 101.9% for authentic injection formulations and 98.0 to 101.0% for authentic tablet formulations. A collaborative study of the method by 6 laboratories resulted in standard deviations of 1.70 and 2.22 for injection and tablet dosage forms, respectively. The method has been adopted official first action.


1987 ◽  
Vol 70 (6) ◽  
pp. 1008-1011 ◽  
Author(s):  
Toshihiro Nagayama ◽  
Toshio Maki ◽  
Kimiko Kan ◽  
Mami Iida ◽  
Taichiro Nishima

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.


1983 ◽  
Vol 66 (4) ◽  
pp. 864-866
Author(s):  
Eileen S Bargo ◽  
◽  
E Aranda ◽  
C Bonnin ◽  
S Hauser ◽  
...  

Abstract A reverse phase high pressure liquid chromatographic method for the determination of oxazepam in tablets and capsules was collaboratively studied by 9 laboratories. Collaborators were supplied with 6 samples that included synthetic and commercial formulations. Tablet and capsule composites are diluted with methanol and filtered. Oxazepam is determined at 254 nm by using a C18 column. Mean recoveries of oxazepam from synthetic tablet and capsule formulations were 97.2 and 99.0%, respectively. Mean coefficients of variation for tablets and capsules ranged from 1.85 to 2.86%. The method has been adopted official first action.


1985 ◽  
Vol 68 (6) ◽  
pp. 1134-1136 ◽  
Author(s):  
Rodney J Bushway

Abstract A liquid chromatographic method has been developed to quantitate pyrethrins in pesticide formulations. Samples were dissolved in tetrahydrofuran (THF) and injected onto an amino column with a solvent system of hexane-nonstabilized THF (90 + 10) at a flow rate of 1.5 mL/min. Detection was monitored at 240 nm and 0.4 AUFS. Total elution time was 7 min. Twelve products varying in concentration from 0.05 to 3.75% and formulated with numerous other ingredients were analyzed. Percent coefficients of variation ranged from 1.39 to 9.68 with the majority less than 5.00. Although piperonyl butoxide and Noctyl bicycloheptene dicarboximide (MGK 264) were not quantitated, neither interfered with the pyrethrin analysis


1975 ◽  
Vol 58 (1) ◽  
pp. 48-49 ◽  
Author(s):  
Manjeet Singh

Abstract A high-pressure liquid chromatographic method is presented for the isolation and determination of uncombined intermediates and subsidiary colors in FD&C Blue No. 2 (indigotine, C.I. No. 73015). Samples of FD&C Blue No. 2 containing 0.1–0.3% isatin, 0.1–0.3% isatin 5-sulfonic acid, 0.1–5.0% monosulfonated indigo, and 1.0–18.0% 5,7’-disulfonated indigo were prepared and analyzed by using this method. Recoveries ranged between 92 and 102%.


1985 ◽  
Vol 68 (1) ◽  
pp. 138-140
Author(s):  
Rajesh Khazanchi ◽  
Nripendra K Roy

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.


1993 ◽  
Vol 76 (6) ◽  
pp. 1248-1254 ◽  
Author(s):  
Louis G M Th Tuinstra ◽  
Arie H Roos ◽  
John M P Van Trijp ◽  
◽  
P A Burdaspal ◽  
...  

Abstract A liquid chromatographic method for determining low aflatoxin M1 concentrations in milk was evaluated in an International Dairy Federation (IDF) interlaboratory study. The study involved 16 participants from 11 countries. The method, chosen after a comparison of several methods by a preparatory group, uses an immunoaffinity column for cleanup. As the sample passes through the column, antibodies selectively bind with aflatoxin M1 (antigen) present and form an antibody-antigen complex. All other components of the sample matrix are washed off the column with water. Then, aflatoxin M1 is eluted from the column with acetonitrile, which is collected. Final determination is carried out by reversed-phase liquid chromatography with fluorescence detection. Over the tested range (80-600 ng aflatoxin M1/kg milk powder), an RSDR ranging from 11 to 23% was obtained by analyzing 24 samples (blind duplicates), 2 samples of which were blanks.


Sign in / Sign up

Export Citation Format

Share Document