Capillary Gas Chromatographic Determination of Thiabendazole in Citrus and Apple Juices

1994 ◽  
Vol 77 (5) ◽  
pp. 1293-1296 ◽  
Author(s):  
Mitsuo Oishi ◽  
Kazuo Onishi ◽  
Itsu Kano ◽  
Hiroyuki Nakazawa ◽  
Shinzo Tanabe
Keyword(s):  
Limit Of Detection ◽  
Simple Procedure ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Fruit Juices ◽  
Reduced Pressure ◽  
Standard Solution ◽  
Juice Sample ◽  
Nitrogen Phosphorus

Abstract A rapid and simple procedure for the determination of thiabendazole (TBZ) residue in citrus and apple juices is described. A juice sample is made basic with 2M NaOH and applied to a disposable Extrelut prepacked column. TBZ is eluted with hexane–ethyl acetate (3 + 1) from the column. The eluate is evaporated to dryness under reduced pressure and then dissolved in an internal standard solution. TBZ is monitored without derivatization by capillary gas chromatography with nitrogen-phosphorus detection. The recoveries of TBZ added to fruit juices at 0.05-1.0 μg/g were 90-96%. The limit of detection of the method for TBZ was 0.01 μg/g. The proposed method is rapid, simple, and sensitive and is applicable to the determination of TBZ in commercial fruit juices.

Gas-Liquid Chromatographic Determination of T-2 Toxin in Plasma

1983 ◽  
Vol 66 (4) ◽  
pp. 909-912 ◽  
Author(s):  
Steven P Swanson ◽  
Venkatachalam Ramaswamy ◽  
Val R Beasley ◽  
William B Buck ◽  
Harold H Burmeister
Keyword(s):  
Chromatographic Method ◽  
Limit Of Detection ◽  
Internal Standard ◽  
Aqueous Sodium Hydroxide ◽  
Chromatographic Determination ◽  
Florisil Column ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract The gas-liquid chromatographic method for the determination of T-2 toxin in plasma is described. The toxin is extracted with benzene, washed with aqueous sodium hydroxide, and chromatographed on a small Florisil column; the heptafluorobutyryl derivative is prepared by reaction with heptafluorobutyrylimidazole. The T-2 HFB derivative is chromatographed onOV-1 at 230°C and measured with an electron capture detector. Iso-T-2, an isomer of T-2 toxin, is added to samples as an internal standard before extraction. Recoveries averaged 98.0 ± 5.5% at levels ranging from 50 to 1000 ng/m L. The limit of detection is 25 ng/mL.

Gas-chromatographic determination of 5-fluorocytosine in human serum.

1976 ◽  
Vol 22 (6) ◽  
pp. 772-776 ◽  
Author(s):  
S A Harding ◽  
G F Johnson ◽  
H M Solomon
Keyword(s):  
Chromatographic Method ◽  
Limit Of Detection ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Mean Value ◽  
Normal Serum ◽  
Trimethylsilyl Derivative ◽  
Serum Samples ◽  
Gas Chromatographic Method

Abstract We describe a sensitive and precise gas-chromatographic method, in which cytosine is used as the internal standard, for determination of an antifungal agent, 5-fluorocytosine, in serum. The trimethylsilyl derivative of this drug is well separated from the internal standard and from normal serum constituents. Amphotericin B does not interfere with the determination of 5-fluorocytosine. The lower limit of detection for 5-fluorocytosine is 1 mg/liter when 200 mul of serum is analyzed. Within-run precision (CV), established by analysis of 10 replicates, was 4.5% at a concentration of 19.9 mg/liter. Twenty-five serum samples were analyzed for 5-fluorocytosine by a microbiological assay and by the gas-chromatographic method. Mean value observed with the bioassay was 78.5 mg/liter and with our procedure was 69.4 mg/liter. When values for our assay were regressed against values for the bioassay, slope of the least-squares line was 0.85, intercept was 2.7 mg/liter, and r was 0.93.

Gas-chromatographic determination of amantadine in human urine.

1980 ◽  
Vol 26 (2) ◽  
pp. 295-296 ◽  
Author(s):  
M J Stumph ◽  
M W Noall ◽  
V Knight
Keyword(s):  
Limit Of Detection ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Organic Layer ◽  
Liquid Chromatographic Method ◽  
Analytical Recovery ◽  
Instrument Response ◽  
Aqueous Layer ◽  
Liquid Chromatographic

Abstract We describe a gas--liquid-chromatographic method for determining the concentration of amantadine hydrochloride in urine with beta-phenylethylamine as internal standard. The urine sample is made alkaline and extracted with 0.5 mL of chloroform. After centrifugation the aqueous layer is aspirated, and an aliquot of the organic layer is injected directly into the gas chromatograph. Concentration and instrument response are linearly related between 2 and 125 mg/L. The limit of detection was 0.5 mg/L. Mean analytical recovery was calculated to be 97%.

Liquid-chromatographic determination of zomepirac in serum and plasma.

1982 ◽  
Vol 28 (3) ◽  
pp. 481-484 ◽  
Author(s):  
C L Welch ◽  
T M Annesley ◽  
H S Luthra ◽  
T P Moyer
Keyword(s):  
High Performance ◽  
Limit Of Detection ◽  
Peak Plasma ◽  
Peak Plasma Concentration ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Liquid Chromatograph ◽  
Days Of Therapy

Abstract We describe a determination of zomepirac concentration in plasma and serum by reversed-phase "high-performance" liquid chromatography. The assay requires 1.0 mL of sample and involves diethyl ether extraction of zomepirac from an acidified sample, followed by concentration and injection into a liquid chromatograph. The column effluent is monitored at 330 nm. Retention times of zomepirac and the internal standard (tolmetin) are 3.8 and 2.7 min, respectively. The lower limit of detection for zomepirac in serum or plasma is 0.05 mg/L. Within-day precision (CV) of analysis in plasma or serum with zomepirac added (0.1-10.0 mg/L) ranged from 1.4 to 6.7%; between-day CV varied from 1.4 to 7.5%. Analytical recovery of zomepirac (1.0 mg/L) from serum and plasma was 77.6 (SD 3.5)% and 80.4 (SD 5.2)%, respectively. Numerous commonly coadministered drugs did not interfere. The elimination half-life of the drug was 1.8 h, and the peak plasma concentration ranged from 1.1 to 2.4 mg/L. Peak and trough concentrations measured throughout five days of therapy imply no accumulation.

Gas-Liquid Chromatographic Determination of Pentachloronitrobenzene in Pesticide Formulations

1976 ◽  
Vol 59 (3) ◽  
pp. 708-710
Author(s):  
Alan R Hanks ◽  
Christine W Cramer
Keyword(s):  
Chromatographic Method ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Peak Height ◽  
Liquid Chromatographic Method ◽  
Pesticide Formulations ◽  
Liquid Chromatographic Determination ◽  
Standard Solution ◽  
Liquid Chromatographic

Abstract A gas-liquid chromatographic method has been developed to determine pentachloronitrobenzene (PCNB) in pesticide formulations including dusts, powders, granules, liquids, and fertilizers. Captan, disulfoton, and Terrazole do not interfere. Samples are extracted with chloroform, and an aliquot is mixed with an equal volume of internal standard solution containing o-terphenyl. PCNB is chromatographed on a 5% SE-30 column and quantitated by peak height ratios. The method has been subjected to a ruggedness test which indicates little sensitivity to changes in extraction and chromatographic conditions.

Gas Chromatographic Determination of Fenpropimorph Residues in Citrus Fruit

1986 ◽  
Vol 69 (5) ◽  
pp. 859-862
Author(s):  
MarÍa Teresa Lafuente ◽  
José Luis Tadeo ◽  
Juan José Tuset
Keyword(s):  
Limit Of Detection ◽  
Citrus Fruit ◽  
Chromatographic Determination ◽  
Specific Detection ◽  
Fungicide Residues ◽  
Washington Navel ◽  
Sample Recovery ◽  
Gas Chromatographic Method ◽  
Nitrogen Phosphorus

Abstract A rapid gas chromatographic method for determining fenpropimorph residues in citrus fruit is reported. The fungicide is extracted with hexane after pH adjustment of the fruit homogenate. A short liquidliquid partitioning process is performed before gas chromatography on an OV-17 column with nitrogen-phosphorus specific detection. The limit of detection of the method was 0.01 mg/kg, based on a 25 g sample. Recovery was always higher than 70%. Fenpropimorph residues in "Washington Navel" oranges and "Hernandina" Clementine fruits dipped in a 1500 mg/L fungicide solution were determined. The fungicide remains mainly in the peel, with levels less than 0.1 mg/kg in the pulp. Fungicide residues in the peel decrease during storage, mainly in Washington Navel peel, where values decreased from 5.2 to 2.8 mg/kg.

Simultaneous liquid-chromatographic determination of prednisone and prednisolone in plasma.

1988 ◽  
Vol 34 (9) ◽  
pp. 1897-1899 ◽  
Author(s):  
M H Cheng ◽  
W Y Huang ◽  
A I Lipsey
Keyword(s):  
High Performance ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Hplc Method ◽  
Liquid Chromatographic Determination ◽  
Standard Solution ◽  
Liquid Chromatographic

Abstract This high-performance liquid-chromatographic (HPLC) method for simultaneous determination of prednisone and its metabolite, prednisolone, in plasma is a modification of the method of Frey et al. (Clin Chem 1979;25:1944-7). Heparinized plasma (1.0 mL) with 0.1 mL of internal standard solution (11-deoxy-17-hydroxycorticosterone, 2 mg/L) is extracted with 7.0 mL of dichloromethane, then washed sequentially with 0.1 mol/L HCl, 0.1 mol/L NaOH, and deionized water, 2.0 mL each. The extract is evaporated and the residue reconstituted with 75 microL of mobile phase, methanol/H2O (40/60 by vol). Thirty microliters of this is injected onto a reversed-phase C6 column, which is eluted at 1.4 mL/min. Analytical recoveries of prednisone and prednisolone were 94-98% and 102-106%, respectively. Day-to-day precision (CV) was 3.8% for prednisone, 6.1% for prednisolone. We encountered no interference from the 21 other steroids and 25 drugs tested. This method is simple, accurate, and precise.

Multiple Internal Standard Technique for the Gas-Liquid Chromatographic Determination of Indole in Shrimp

1978 ◽  
Vol 61 (1) ◽  
pp. 136-138
Author(s):  
Walter F Staruszkiewicz ◽  
John F Bond
Keyword(s):  
Silica Gel ◽  
Room Temperature ◽  
Internal Standard ◽  
Standard Technique ◽  
Chromatographic Determination ◽  
Experimental Conditions ◽  
Liquid Chromatographic Determination ◽  
Standard Solution ◽  
Liquid Chromatographic

Abstract A multiple internal standard technique has been developed for the official first action gas-liquid chromatographic (GLC) method for determining indole in shrimp. The modification was developed because interfering GLC peaks are occasionally observed when 2-methylindole is used as the internal standard. An internal standard solution containing 1-methylindole, 2- methylindole, and diphenylamine was added to extracts of shrimp before silica gel cleanup and separation by GLC. All of the compounds were quantitatively recovered and were separated on the GLC column under identical experimental conditions. Extracts of acceptable shrimp to which indole was added at levels of 3–10 μg/ 100 g and extracts of decomposed shrimp were stored at room temperature for 2 weeks. Average and maximum changes (μg indole/100 g) during storage were, respectively, for each internal standard: average 0.6, 0.4, and 1.1; maximum 1.7, 0.9, and 2.9.

Simultaneous liquid-chromatographic determination of 12 common sedatives and hypnotics in serum.

1978 ◽  
Vol 24 (4) ◽  
pp. 657-662 ◽  
Author(s):  
P M Kabra ◽  
H Y Koo ◽  
L J Marton
Keyword(s):  
Serum Proteins ◽  
Limit Of Detection ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Acetonitrile Solution ◽  
Column Temperature ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract We present a method for simultaneously determining 12 hypnotics and sedatives (primidone, methyprylon, phenobarbital, butabarbital, butalbital, ethchlorvynol, pentobarbital, amobarbital, phenytoin, glutethimide, secobarbital and methaqualone) in 200 microliter of serum. Serum proteins are precipitated with an acetonitrile solution containing 5-(4-methylphenyl)-5-phenylhydantoin, the internal standard. The drugs are eluted from a reversed-phase column with a mobile phase consisting of an acetonitrile/phosphate buffer, at a flow rate of 3.0 ml/min. The eluted drugs are detected by their absorption at 195 nm; their quantities are estimated from their peak heights. Each analysis requires no longer than 30 min at the optimum column temperature of 50 degrees C. The lower limit of detection for all of these drugs is less than 10 ng/sample for drug standard. A sensitivity of 1.0 mg/liter of serum is attained routinely for each of the drugs. Analytical recoveries for the 12 drugs varied from 94 to 112%, with good day-to-day precision (CV between 3.8 and 10.4%). Of more than 35 drugs tested for possible interference, only ethotoin interferes with the analysis of phenobarbital.

Gas-Liquid Chromatographic Determination of Fluchloralin in Formulations

1977 ◽  
Vol 60 (5) ◽  
pp. 1145-1147
Author(s):  
Gregory S Grimes
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Reference Standard ◽  
Relative Standard ◽  
Liquid Chromatographic Determination ◽  
Standard Solution ◽  
Liquid Chromatographic

Abstract A gas-liquid chromatographic (GLC) method has been developed that is precise, rapid, simple, and specific for fluchloralin in emulsifiable liquid formulation. Sample and reference standard are weighed, internal standard solution is added, and an aliquot of the mixture is injected onto the chromatographic column. Fluchloralin gives a sharp symmetrical peak at about 5.4 min. The internal standard has a broader symmetrical peak at about 6.9 min. The relative standard deviation for 21 consecutive injections of the standard solution was 0.3773%. The method was compared with the official GLC method, 6.210–6.215, for the structurally similar trifluralin. Fluchloralin gave a sharp symmetrical peak at about 8.5 min; the internal standard had a sharp symmetrical peak at about 9.2 min. The relative standard deviation of 21 consecutive injections of reference standard solution was 0.6988%. Comparison of the variances of the 2 methods by the F-test at the 99% confidence level showed that the proposed method demonstrated substantially better precision.

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