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.

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).

Gas-Liquid Chromatographic Determination of Pyridazinones in Technical Products and Formulations

1978 ◽  
Vol 61 (1) ◽  
pp. 161-163
Author(s):  
Giuseppe Cellerino ◽  
Mariarosa Re
Keyword(s):  
Internal Standard ◽  
Standard Technique ◽  
Chromatographic Determination ◽  
Gas Liquid Chromatography ◽  
Flame Ionization ◽  
Selective Detector ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Technical Products

Abstract Simultaneous determination of the active ingredient and of by-products in technical and formulated pyridazinones was rapidly performed by gas-liquid chromatography with complete resolution of all compounds. Quantitative determination by the internal standard technique is accurate and precise. The lower limit of detectability is 8 × 10–12 g/sec with a flame ionization detector and 1 × 10–12 g/sec with a nitrogen-phosphorus selective detector operating in the nitrogen mode.

Liquid Chromatographic Determination of Carbamazepine in Tablets

1988 ◽  
Vol 71 (3) ◽  
pp. 523-525 ◽  
Author(s):  
Ella S Walker
Keyword(s):  
Internal Standard ◽  
Standard Technique ◽  
Chromatographic Determination ◽  
Individual Values ◽  
Qualitative And Quantitative ◽  
Average Value ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A simple and rapid liquid chromatographic method is described for the qualitative and quantitative determination of carbamazepine in tablet composites and individual tablets, using the internal standard technique. Analyses were performed on a C-18 reverse-phase column with tetrahydrofuran-methanol-water (8 + 37 + 55) as the mobile phase. A linear relationship was obtained between detector responses at 254 nm and amounts of carbamazepine injected ranging from 0.2 to 1.7 ng. The coefficient of variation for 10 consecutive injections of a standard preparation was 0.4%. Recoveries of carbamazepine from 100 and 200 mg tablets averaged 101.4 and 99.7%, respectively. Assay results for commercial tablets analyzed by the proposed method agreed favorably with those obtained by the method of USP XXI. The assay results for individual tablets indicated that deviations from the average value and the range of individual values are much wider with the compendial method than with the proposed method

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.

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.

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.

Gas-Liquid Chromatographic Determination of Hexestrol Residues in Adipose Tissue

1981 ◽  
Vol 64 (3) ◽  
pp. 709-713
Author(s):  
Hisaya Tobioka ◽  
Ryoji Kawashima
Keyword(s):  
Adipose Tissue ◽  
Silica Gel ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Optimum Ratio ◽  
Extraction And Purification ◽  
Percent Recovery ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A gas-liquid chromatographic (GLC) method is described for determining hexestrol residues in adipose tissue. The extraction and purification procedures were based on a published method for determining diethylstilbestrol. To increase precision and sensi-(ivy, the sample was further cleaned up by silica gel column chromatography. The heptafluorobutyric (HFB) derivative of hexestrol was used for GLC analysis with HFB-docosanol as an internal standard. A variety of acetone-benzene mixtures were compared to determine the optimum ratio for hexestrol acylation. Acetone-benzene (90 + 10) or 100% acetone provided 16% higher GLC response than did a 50 – 50 mixture (P <0.001) and was selected for use in the acylation procedure. A system for evaporating excess reagents was also studied. Overall percent recovery reached 72 ± 5. The method can be used to determine residual hexestrol at the 0.1 ppb level.

Gas-Liquid Chromatographic Determination of Paraldehyde in Paraldehyde Elixir

1972 ◽  
Vol 55 (1) ◽  
pp. 166-169
Author(s):  
William T Lampkin
Keyword(s):  
Collaborative Study ◽  
Internal Standard ◽  
Pharmaceutical Preparations ◽  
Standard Technique ◽  
Chromatographic Determination ◽  
Flame Ionization ◽  
Glass Column ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A collaborative study was conducted on a GLC method for determining paraldehyde in pharmaceutical preparations of paraldehyde elixirs. Eleven collaborating laboratories analyzed 2 unknown paraldehyde solutions and a solution of known paraldehyde concentration. Recoveries of 15–25% paraldehyde solutions averaged 98.5% with a coefficient of variation of about 2%. The method consists of diluting a sample aliquot to a definite volume and determining the paraldehyde content by GLC, using a flame ionization detector and a 6’ × 4 mm coiled glass column packed with 80–100 mesh Diatoport S coated with 2% HIEFF-8BP (cyclohexane dimethanol succinate) plus 20% Carbowax 20M. The internal standard technique was used for calculation. It is recommended that the method be adopted as official first action.

Liquid-chromatographic determination of amiodarone and N-desethylamiodarone in serum

1990 ◽  
Vol 36 (3) ◽  
pp. 532-534 ◽  
Author(s):  
C N Ou ◽  
C L Rognerud ◽  
L T Duong ◽  
V L Frawley
Keyword(s):  
Internal Standard ◽  
Chromatographic Determination ◽  
Isopropyl Ether ◽  
Organic Layer ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Standard Solution ◽  
Liquid Chromatographic

Abstract We have developed a stable and simple normal-phase liquid-chromatographic method for simultaneously measuring amiodarone and its metabolite, N-desethylamiodarone, within 8 min. The chromatographic system consists of a 15 cm x 3.9 mm Waters "Resolve" silica column and a mobile phase of ammonium sulfate (17 mmol/L, pH 6.8) and methanol (8/92 by vol), pumped at 1.8 mL/min and monitored at 254 nm. After 250 microL of serum is mixed with 100 microL of 0.36 mol/L NaH2PO4, 100 microL of the internal standard solution (L8040, 6 mg/L), and 200 microL of isopropyl ether, the mixture is vortex-mixed and centrifuged. Fifty microliters of the organic layer is injected onto the column. Relative recovery was 100% over the assay range of 0.1 to 20.0 mg/L for both compounds. Within-run and total (day-to-day) CVs were 3% and 7% for amiodarone and 5% and 8% for N-desethylamiodarone, respectively.

High Performance Liquid Chromatographic Determination of Fructose, Glucose, and Sucrose in Molasses

1980 ◽  
Vol 63 (3) ◽  
pp. 476-480 ◽  
Author(s):  
Carolyn E Damon ◽  
Bruce C Pettitt
Keyword(s):  
High Performance ◽  
Reducing Sugars ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
High Performance Liquid Chromatographic ◽  
Cleanup Procedure ◽  
Liquid Chromatographic Determination ◽  
Standard Solution ◽  
Liquid Chromatographic

Abstract Fructose, glucose, and sucrose were determined quantitatively in molasses by high performance liquid chromatography (HPLC) using maltose as an internal standard. After a simple cleanup procedure, chromatographic separation required less than 20 min for the 17 molasses samples. HPLC gave lower results for reducing sugars (fructose plus glucose) and for sucrose by an average of 3.9 and 1.2%, respectively, when compared to results obtained by classical methods. The lower values are believed to result from elimination of interfering substances by this method. The values probably reflect more accurately the true composition of the molasses. Repetitive injections of a standard solution indicated a coefficient of variation of 2.0% for fructose and glucose and of 2.2% for sucrose.

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