scholarly journals Simultaneous liquid-chromatographic determination of three antiarrhythmic drugs: disopyramide, lidocaine, and quinidine.

1980 ◽  
Vol 26 (2) ◽  
pp. 197-200 ◽  
Author(s):  
J G Flood ◽  
G N Bowers ◽  
R B McComb
Keyword(s):  
Mobile Phase ◽  
Antiarrhythmic Drugs ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Peak Height ◽  
Reversed Phase ◽  
Multiple Drug ◽  
Evaporation Technique ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract We report a common methodology for determining three antiarrhythmic drugs: disopyramide, lidocaine, and quinidine. Alkalinized serum and internal standard (p-chlorodisopyramide) are extracted into dichloromethane, the organic phase is evaporated, and the redissolved residue is injected onto a reversed-phase column (micron Bondapack C18). Quantitation is via peak-height ratios of analyte vs internal standard (as detected at 205 nm) referenced to a serum-based multiple-drug standard. A mobile phase of 30 mmol/L phosphate buffer and acetonitrile (72/28 by vol) is used. These conditions yiel; optimum separation and band symmetry for the analytes and some of their metabolites. Crucial factors in this simultaneous assay include pH of the mobile phase and injected solution, extraction time, and evaporation technique. Day-to-day precision (CV) for all drugs was less than 5%, and correlation with other assay techniques for each drug is reported. The method enables more efficient use of personnel and instrumentation without sacrificing analytical quality.

Simultaneous liquid-chromatographic determination of three antiarrhythmic drugs: disopyramide, lidocaine, and quinidine.

1980 ◽  
Vol 26 (2) ◽  
pp. 197-200
Author(s):  
J G Flood ◽  
G N Bowers ◽  
R B McComb
Keyword(s):  
Mobile Phase ◽  
Antiarrhythmic Drugs ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Peak Height ◽  
Reversed Phase ◽  
Multiple Drug ◽  
Evaporation Technique ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract We report a common methodology for determining three antiarrhythmic drugs: disopyramide, lidocaine, and quinidine. Alkalinized serum and internal standard (p-chlorodisopyramide) are extracted into dichloromethane, the organic phase is evaporated, and the redissolved residue is injected onto a reversed-phase column (micron Bondapack C18). Quantitation is via peak-height ratios of analyte vs internal standard (as detected at 205 nm) referenced to a serum-based multiple-drug standard. A mobile phase of 30 mmol/L phosphate buffer and acetonitrile (72/28 by vol) is used. These conditions yiel; optimum separation and band symmetry for the analytes and some of their metabolites. Crucial factors in this simultaneous assay include pH of the mobile phase and injected solution, extraction time, and evaporation technique. Day-to-day precision (CV) for all drugs was less than 5%, and correlation with other assay techniques for each drug is reported. The method enables more efficient use of personnel and instrumentation without sacrificing analytical quality.

Improved liquid-chromatographic determination of haloperidol in plasma.

1984 ◽  
Vol 30 (7) ◽  
pp. 1228-1230 ◽  
Author(s):  
A K Dhar ◽  
H Kutt
Keyword(s):  
Mobile Phase ◽  
High Performance ◽  
Room Temperature ◽  
Internal Standard ◽  
Isoamyl Alcohol ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract This method for determination of haloperidol in plasma is based on "high-performance" isocratic liquid chromatography with the use of a C8 bonded reversed-phase column at room temperature. Haloperidol and the internal standard (chloro-substituted analog) are extracted from alkalinized plasma into isoamyl alcohol/heptane (1.5/98.5 by vol) and back-extracted into dilute H2SO4. The aqueous phase is directly injected onto the column. The mobile phase is a 30/45/25 (by vol) mixture of phosphate buffer (16.5 mmol/L, pH 7.0), acetonitrile, and methanol. Unlike other liquid-chromatographic procedures for haloperidol, commonly used psychotropic drugs do not interfere. Analysis can be completed within an hour. The procedure is extremely sensitive (1.0 microgram/L) and is well reproducible (CV 5.6% for a 2.5 micrograms/L concentration in plasma).

Improved liquid-chromatographic determination of 3-methoxy-4-hydroxyphenylethyleneglycol in urine with electrochemical detection.

1984 ◽  
Vol 30 (1) ◽  
pp. 140-143 ◽  
Author(s):  
J R Shipe ◽  
J Savory ◽  
M R Wills
Keyword(s):  
Mobile Phase ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Improved Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Mean Concentration ◽  
Phase Column

Abstract In this improved method for quantifying 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG) in urine, after a multistep extraction of MHPG and internal standard (iso-MHPG) from 3.0 mL of urine, the compounds are separated on a C18 reversed-phase column and quantified by use of an electro-chemical detector. The isocratic chromatographic separation takes about 16 min. The mobile phase is phosphate buffer/acetonitrile (88/12 by vol), the flow rate 0.7 mL/min. Recycling the mobile phase and automating the sample injection make possible the unattended assay of more than 70 samples per day. The within-run precision of the method is excellent (CV 1.8%) at a mean concentration of 1.1 mg/L.

Liquid-chromatographic determination of pentobarbital in plasma with use of a resin column and an alkaline mobile phase.

1982 ◽  
Vol 28 (8) ◽  
pp. 1772-1774 ◽  
Author(s):  
R N Gupta ◽  
P T Smith ◽  
F Eng
Keyword(s):  
Mobile Phase ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Enhanced Sensitivity ◽  
Acidic Drugs ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract We describe a liquid-chromatographic method involving a new, nonsilica column (XAD-2, Hamilton Co.) for pentobarbital in plasma. Plasma is extracted with chloroform after addition of the internal standard, 5-ethyl-5-p-tolyl-barbituric acid. Acidic drugs are back-extracted into alkali, then chromatographed on the resin-base reversed-phase column. The use of alkaline mobile phase allows enhanced sensitivity and detection of barbiturates at 240 nm. The within-run CV for 10 samples was 1.9%, the between-run CV 1.8%. Ten commonly used barbiturates are separated isocratically in less than 15 min. Other commonly prescribed acidic drugs do not interfere with determination of pentobarbital.

Liquid-chromatographic determination of alpha- and gamma-tocopherols in erythrocytes, with fluorescence detection.

1983 ◽  
Vol 29 (10) ◽  
pp. 1840-1842 ◽  
Author(s):  
J Lehmann ◽  
H L Martin
Keyword(s):  
Mobile Phase ◽  
High Performance ◽  
Limit Of Detection ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract We have adapted to erythrocytes a method for the determination of alpha- and gamma-tocopherols in plasma and platelets. Erythrocytes (50 microL) were extracted with methanol containing tocol (internal standard) and pyrogallol. Tocopherols were partitioned into chloroform, washed, and injected in methanol onto a reversed-phase (C18) "high-performance" liquid-chromatographic column. The mobile phase was methanol/water (99/1 by vol) at a flow rate of 2 mL/min and detection was with a "high-performance" spectrophotofluorometer. The limit of detection for either tocopherol is 0.10 microgram/mL of packed cells. Analytical recoveries ranged from 93 to 104%. Some values for tocopherols in human erythrocytes are presented.

High Pressure Liquid Chromatographic Determination of Phenol in Honey

1981 ◽  
Vol 64 (2) ◽  
pp. 337-339
Author(s):  
Peter Sporns
Keyword(s):  
High Pressure ◽  
Mobile Phase ◽  
Silicic Acid Column ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Peak Height ◽  
High Pressure Liquid Chromatographic ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A method is described for determining phenol in honey by using high pressure liquid chromatography (HPLC). An internal standard, 2-phenylethanol, was added to honey which was steam-distilled and chromatographed on a 25 cm × 3.2 mm id Spherisorb 5 µm silicic acid column using water as the mobile phase. Absorbance was monitored at 195 nm. Using a mixed standard of known concentration and peak height measurements, the amount of phenol in the honey could be quantitated. Recovery of added phenol was checked at levels from 0.1 to 33 ppm.

Liquid-chromatographic determination of two antidepressants, trazodone and mianserin, in plasma.

1984 ◽  
Vol 30 (2) ◽  
pp. 230-233 ◽  
Author(s):  
S H Wong ◽  
S W Waugh ◽  
M Draz ◽  
N Jain
Keyword(s):  
Organic Phase ◽  
Mobile Phase ◽  
Geriatric Patients ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Peak Height ◽  
Dilute Acid ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract Plasma containing trazodone or mianserin was extracted. The organic phase containing trazodone was evaporated and the residue was reconstituted in dilute acid. Mianserin was back-extracted from the organic phase with dilute acid. Both drugs were chromatographed on mu Bondapak C18 columns, with phosphate/acetonitrile as the mobile phase. Peak-height ratios of drug/internal standard were linearly correlated with concentrations between 25 and 2000 micrograms/L for trazodone, and between 25 and 200 micrograms/L for mianserin, with respective between-run CVs of 4.7% and 7.6%. Detection limits were 5 ng. Of some common drugs and metabolites examined, nortriptyline co-elutes with the internal standard used in the trazodone assay, while flurazepam co-elutes with mianserin. Concentrations of trazodone in 26 patients ranged from 73 to 1678 micrograms/L. For two geriatric patients, concentrations were about 2000 micrograms/L. For two overdose patients, they were about 5000 micrograms/L. The concentration of mianserin was 27 micrograms/L for a volunteer treated with a single 40-mg oral dose.

Liquid-chromatographic determination of ciprofloxacin in serum and urine.

1985 ◽  
Vol 31 (5) ◽  
pp. 684-686 ◽  
Author(s):  
D E Nix ◽  
J M De Vito ◽  
J J Schentag
Keyword(s):  
Mobile Phase ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Multiple Drug ◽  
Serum Samples ◽  
Acid Urine ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Serum And Urine

Abstract We describe the liquid-chromatographic determination of ciprofloxacin in patients' serum and urine. Serum samples were prepared by precipitating protein with perchloric acid. Urine samples were diluted 100-fold with mobile phase. The mobile phase, consisting of pH 3 phosphate buffer/acetonitrile/methanol (81/5/14, by vol), was pumped through a mu Bondapak C18 reversed-phase column at 1.5 mL/min. Fluorescence of the effluent was monitored, at wavelengths for excitation and emission of 270 and 440 nm, respectively. Standard curves were linearly related to concentration from 0.08 to 10 mg/L for serum, 1 to 20 mg/L for urine. The procedure was evaluated in a clinical setting to determine its usefulness in studying the pharmacokinetics of ciprofloxacin in patients with concurrent diseases and receiving multiple drug therapies.

High Pressure Liquid Chromatographic Determination of Fensulfothion: Collaborative Study

1983 ◽  
Vol 66 (3) ◽  
pp. 801-803
Author(s):  
Margie E Owen ◽  
◽  
O O Bennett ◽  
L T Chenery ◽  
C J Cohen ◽  
...  
Keyword(s):  
Coefficient Of Variation ◽  
Collaborative Study ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Peak Height ◽  
Matched Pair ◽  
Standard Material ◽  
Liquid Chromatographic Determination ◽  
The Difference ◽  
Liquid Chromatographic

Abstract A method for analyzing fensulfothion was tested by 10 collaborators. Formulations were dissolved, or extracted from inerts, in methanol. Benzophenone was used as an internal standard. The solution was diromatographed on a Partisil-10 ODS-2, or equivalent, reverse phase column, and detected at 230 nm. A mobile phase of methanol-water-phosphoric acid was used. The ratio of fensulfothion peak height to benzophenone peak height was calculated from the UV response and compared to the standard material for quantitation. A 15% granular formulation was analyzed as a matched pair. The results of one collaborator were outliers by the Dixon test. The coefficient of variation for the granular formulation was 1.6%. A matched pair of 63% spray concentrate samples was analyzed by 10 collaborators. The difference in results was an outlier for one collaborator; the coefficient of variation for the other collaborators was 1.5%. The method has been adopted official first action.

Liquid Chromatographic Determination of Diclazuril in Premix and Supplemented Feed: Interlaboratory Study

1994 ◽  
Vol 77 (6) ◽  
pp. 1359-1361 ◽  
Author(s):  
Andre Fontaine ◽  
Karel Haustraete
Keyword(s):  
Solid Phase ◽  
Collaborative Study ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Peak Height ◽  
Reversed Phase ◽  
Poultry Feed ◽  
Uv Detector ◽  
Relative Standard ◽  
Liquid Chromatographic

Abstract Diclazuril, Janssen Research Compound R 64433 (Clinacox), is analyzed by liquid chromatography (LC). Compound R 062646, with a structure analogous to that of diclazuril, is used as internal standard. The drug is extracted from feed with acidified methanol. Diclazuril is then isolated by solid-phase extraction (SPE) with a cartridge containing a C18 phase. The eluate is evaporated, and the residue is redissolved in dimethylformamide. An aliquot is injected onto a reversed-phase ODS LC column, and the drug quantitated at 280 nm with a UV detector. Peak areas are obtained at the retention times corresponding to the internal standard and diclazuril. The quantity of active ingredient is determined by comparing the ratio of the peak height of diclazuril to that of internal standard in the sample with the same ratio in a single calibration solution. SPE is not necessary for the analysis of premixes. Eleven laboratories participated in the collaborative study. Laboratories were provided with 2 samples of premixes and 3 samples of feed for poultry. Feed sample K1 was sent to only 6 laboratories. The reproducibility relative standard deviations (RSDRS) were 7.38 and 7.53% for the 2 premixes and 9.67,13.65, and 18.61% for the 3 samples of supplemented feed.

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