Quantitative gas-chromatographic flame-ionization method for p-chlorophenoxyisobutyric acid in human serum and saliva.

1976 ◽  
Vol 22 (6) ◽  
pp. 884-888 ◽  
Author(s):  
J N Connor ◽  
G F Johnson ◽  
H M Solomon
Keyword(s):  
Human Serum ◽  
Extraction Procedure ◽  
Average Dose ◽  
Unbound Fraction ◽  
Butyl Esters ◽  
Flame Ionization ◽  
Double Extraction ◽  
High Concentrations ◽  
Gas Chromatographic Method ◽  
Chlorophenoxyisobutyric Acid

Abstract We describe a gas-chromatographic method for p-chlorophenoxyisobutyric acid (I) the active metabolite of clofibrate. The drug and internal standards are separated from either serum or saliva by a double extraction procedure and converted to the corresponding butyl esters by reaction with iodobutane in a mixture of methanol and N,N-di-methylacetamide containing tetramethylammonium hydroxide. Within-run CV of this assay at a serum I concentration of 79.2 mg/liter was 2.3% and at a salivary I concentration of 2.5 mg/liter was 2.1%. Precision during four months of the serum and salivary assays at these concentrations was 4.1% and 6.2%, respectively. The mean serum concentration of I (12 h after dose) in patients receiving the drug at an average dose of 28.0 mg/kg per day was 109.6 mg/liter. Serum and salivary concentrations of I as determined by our procedure were used to calculate the unbound fraction of drug in human serum. Such measurements can be used to monitor therapy in patients with renal disease, where drug toxicity may arise from high concentrations of unbound I.

Measurement of felbamate by wide-bore capillary gas chromatography and flame ionization detection

1994 ◽  
Vol 40 (5) ◽  
pp. 745-748 ◽  
Author(s):  
N Rifai ◽  
D Fuller ◽  
T Law ◽  
M Mikati
Keyword(s):  
Extraction Procedure ◽  
Stability Study ◽  
Therapeutic Monitoring ◽  
Antiepileptic Agent ◽  
Flame Ionization ◽  
Generalized Seizures ◽  
Drug Concentrations ◽  
Wide Range ◽  
Simple Extraction ◽  
Gas Chromatographic Method

Abstract Felbamate, a newly developed antiepileptic agent, has been demonstrated to control partial and generalized seizures effectively. We have developed a gas-chromatographic method for the determination of felbamate, using a wide-bore capillary column, a flame ionization detector, and a simple extraction procedure. The assay day-to-day precision (n = 20) was 5.2% and 3.6% for drug concentrations of 50 and 150 mg/L, respectively; average recovery over a wide range of felbamate concentrations was 95%; the detection limit was 5 mg/L; and assay linearity extended to 300 mg/L. Although 9 of the 27 drugs tested were coextracted with felbamate, they exhibited significantly different retention times and showed no interference. A short-term stability study showed that plasma felbamate is stable at 4, -20, or -78 degrees C for at least 1 month. Plasma felbamate concentrations in 66 pediatric patients ranged from 7 to 154 mg/L (mean +/- SD 44 +/- 24.7). We consider the method ideally suited for therapeutic monitoring of plasma felbamate concentration.

DIRECT MEASUREMENT OF ARGININE-VASOPRESSIN IN HUMAN SERUM WITHOUT EXTRACTION PROCEDURE

1975 ◽  
Vol 80 (1_Suppla) ◽  
pp. S130 ◽  
Author(s):  
H. Wagner ◽  
V. Maier ◽  
H.-J. Herrmann ◽  
H. E. Franz
Keyword(s):  
Human Serum ◽  
Direct Measurement ◽  
Arginine Vasopressin ◽  
Extraction Procedure

Ayurvedic formulations containing benzoic and ascorbic acids as additives: benzene formation during storage and impact of additives on quality parameters

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Priyanka Sharma ◽  
Mukesh Maithani ◽  
Vikas Gupta ◽  
Parveen Bansal
Keyword(s):  
Ascorbic Acid ◽  
Quality Parameters ◽  
Over The Counter ◽  
Flame Ionization ◽  
Class 1 ◽  
Short And Long Term ◽  
Pharmaceutical Industries ◽  
Increasing Demand ◽  
Gas Chromatographic Method ◽  
Ascorbic Acids

AbstractObjectivesAyurvedic formulations are becoming the prior choice of people as health care supplements. The increasing demand for these formulations has led to extensive development of Ayurvedic pharmaceutical industries worldwide. The reaction between the preservatives (sodium benzoates and ascorbic acid) used in these formulations could generate benzene. Benzene is classified as class-1 human carcinogen and responsible for various short and long term health effects.MethodsIn this study, 25 formulations (containing ascorbic acid and sodium benzoate) of various manufacturers available as over the counter products were obtained and their benzene content were determined using gas chromatograph with flame ionization detector.ResultsThe result showed that 64% of the formulations were free from benzene contamination whereas 36% of formulations were found to be contaminated with benzene. A simple, less time-consuming, economic, and validated gas chromatographic method for estimation of benzene in Ayurvedic formulations was also developed successfully in present study.ConclusionsThe data revealed that the level of benzene was within permissible limits, yet the presence of a carcinogen in the marketed formulations intended for internal use is an alarming situation.

HPLC Analysis of Oxytetracycline Residues in Honey

1986 ◽  
Vol 49 (5) ◽  
pp. 383-388 ◽  
Author(s):  
PETER SPORNS ◽  
SUET KWAN ◽  
LAWRENCE A. ROTH
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Aqueous Solutions ◽  
High Performance ◽  
Hplc Analysis ◽  
Extraction Procedure ◽  
Hplc Method ◽  
Limits Of Detection ◽  
Ph Values ◽  
Double Extraction

Oxytetracycline (OTC), also known commercially as Terramycin, was determined to be more stable in honey than in buffered aqueous solutions at similar pH values and temperatures. A rapid high performance liquid chromatography (HPLC) method was developed to detect and quantitate OTC using a 1:1 dilution (wt/wt) of honey samples in water. Using 355 nm as the wavelength of detection, amounts as low as 0.5 μg/ml could be detected in the above solution. The limits of detection were lowered considerably by a double extraction procedure.

Gas Chromatographic Method for Determination of Dimethylamine, Trimethylamine, and Trimethylamine Oxide in Fish-Meat Frankfurters

1991 ◽  
Vol 74 (2) ◽  
pp. 400-403
Author(s):  
Walter Fiddler ◽  
Robert C Doerr ◽  
Robert A Gates
Keyword(s):  
Atlantic Menhaden ◽  
Chromatographic Technique ◽  
Acid Extraction ◽  
Fish Meat ◽  
Flame Ionization ◽  
Trimethylamine Oxide ◽  
Headspace Gas ◽  
Gas Chromatographic Method ◽  
Gas Tight

Abstract A method Is described for analysis of minced fish-meat and surlmi-meat frankfurters for dimethylamine (DMA), trimethyiamine (TMA), and trimethyiamine oxide (TMAO) using a headspace-gas chromatographic technique. After simple acid extraction and addition of NaOH, the headspace was directly Injected Into a gas chromatograph by a gas-tight syringe. DMA and TMA were separated on a Chromosorb 103 column and detected by a flame Ionization detector. TMAO was measured as TMA after Zn reduction. Repeatability of the method for DMA, TMA, and TMAO was 6.6,1.0, and 18.8 ppm, respectively. The method was applicable to Alaska pollock-meat and Atlantic menhaden-meat frankfurters, unwashed, and washed mince and surlml.

RADIOIMMUNOASSAYS OF 3,5,3′-TRIIODO-L-THYRONINE WITH AND WITHOUT A PRIOR EXTRACTION STEP

1975 ◽  
Vol 80 (1) ◽  
pp. 58-69 ◽  
Author(s):  
A. Burger ◽  
C. Sakoloff ◽  
V. Staeheli ◽  
M. B. Vallotton ◽  
S. H. Ingbar
Keyword(s):  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Normal Values ◽  
Covalent Binding ◽  
Extraction Procedure ◽  
Mixed Population ◽  
Coupling Agents ◽  
Extraction Step ◽  
The Mean

ABSTRACT Two radioimmunoassays for triiodothyronine (T3) are described, one of which includes an extraction step, while the other does not. To raise antibodies, two carrier proteins and different coupling agents were used, namely haemocyanin and diazotized benzidine or human serum albumin and carbodiimide. In the case of T3 coupled to haemocyanin by diazotized benzidine, evidence of covalent binding of the hapten to the protein was obtained. In the case of T3 coupled to human serum albumin, little evidence of covalent linkage was available. Nevertheless immunization was successful in both cases. The radioimmunoassay in unextracted serum was highly reproducible and precise (intra-assay variability 5.2% inter-assay variability 8.1%). Normal values were determined which clearly indicate a fall in the serum T3 concentration with increasing age. In men the fall occurs in the fifth decade. In women the T3 starts to fall only after 70 years of age. In 31 cases of hyperthyroidism the serum T3 concentration ranged from 2.26 to 10.4 ng T3/ml. In 10 cases of hypothyroidism the values ranged from 0 to 0.8 ng T3/ml. The radioimmunoassay using an extraction procedure was less extensively used since it was found to be less reproducible (intra-assay variability 7.5%, inter-assay 12.25%). The normal values were determined with a mixed population aged 20–50. The mean ± 2 sd was 0.9 ± 0.36 ng T3/ml (n=52). In 17 cases of hypothyroidism the values ranged from 0 to 0.6 ng T3/ml and in 22 cases of hyperthyroidism from 2 to 14.4 ng T3/ml.

A new gas chromatographic method for determination of amino acid levels in human serum

1980 ◽  
Vol 105 (2) ◽  
pp. 201-211 ◽  
Author(s):  
Hartmut Frank ◽  
Albert Rettenmeier ◽  
Helmut Weicker ◽  
Graeme J. Nicholson ◽  
Ernst Bayer
Keyword(s):  
Amino Acid ◽  
Human Serum ◽  
Chromatographic Method ◽  
Amino Acid Levels ◽  
Gas Chromatographic Method

scholarly journals Investigation of pesticide residues in surface water in some areas of agricultural production at Ho Chi Minh city

2013 ◽  
Vol 16 (3) ◽  
pp. 106-119
Author(s):  
Phu Ly Sy Nguyen ◽  
Nguyen Duc Do ◽  
Hien Thi To
Keyword(s):  
Surface Water ◽  
Pesticide Residues ◽  
Agricultural Production ◽  
Chromatographic Method ◽  
Organophosphorus Pesticides ◽  
Ho Chi Minh City ◽  
Growth Stages ◽  
High Concentrations ◽  
Gas Chromatographic Method ◽  
Agricultural Areas

Residual levels of organochlorine and organophosphorus pesticides in surface water in some agricultural areas at Ho Chi Minh City were investigated in 2012. Four organophosphorus pesticides including Malathion, Parathion, Ethion and Trithion and seven organochlorine pesticides including Alpha - HCH, beta-HCH, gammaHCH, aldrin, Heptachlor – epoxide, AlphaEndosulfan and Endosulfan-sulfate were determined in the surface water in four dicstricts : Binh Chanh, Hoc Mon, Cu Chi and Binh Tan using gas chromatographic method with electron capture detector (GCECD). The results showed that residues of pesticide were found with high concentrations in surface water in agricultural areas and pesticide residues changed depending on growth stages of crops. The concentration and distribution of pesticides were different in the water samples at different sites. Residues of pesticides such as Parathion, Ethion and Trithion were detected in surface water although these chemicals had been banned.

scholarly journals The influence of roasting conditions on volatile flavour compounds in raw and roasted cashew kernels (Anacadium ocidentale) grown in Nigeria

2019 ◽  
Vol 11 (1) ◽  
pp. 1-10
Author(s):  
Olawale Paul Olatidoye ◽  
Taofik Akinyemi Shittu ◽  
Samuel Olusegun Awonorin ◽  
Emmanuel Sunday Akin Ajisegiri
Keyword(s):  
Volatile Compounds ◽  
Extraction Procedure ◽  
Consumer Acceptability ◽  
Volatile Fraction ◽  
Flavour Compounds ◽  
Overall Acceptability ◽  
Flame Ionization ◽  
Volatile Flavour ◽  
Steam Distillation Extraction ◽  
Temperature Time

The use of inappropriate temperature-time combinations during the roasting of nuts could lead to quality defects, such as burnt taste, short shelf-life, rancidity, and poor flavour. In this study, cashew kernels were roasted in a forced airflow-drying oven for 20, 40,and 60 min at 100, 120, 140, and 160°C. The productswere evaluated for volatile flavour compounds and the sensory evaluation of the roasted cashew kernelsat different roasting conditions. The volatile fraction was isolated using the combined steam distillation–extraction procedure and identified by gas chromatography–flame-ionization detection (GC-FID). The consumer acceptability test was carried out by 100 panellists using nine point hedonic scales to assess preferences for like or dislike, colour, taste, texture, flavour,and overall acceptability. It was found that there were significant differences in flavour compounds between the different conditions of roasting. Twenty-nine volatile compounds were identified in both fresh and roasted cashew kernelscomprising five main classes,which consist of 12 hydrocarbons, eight aldehydes, four ketones, three alcohols,and one acid. The volatile compounds(mg/100g) ranged from 5.03x10-2to 1.20 (2-butanone), 7.46x10-6to 1.85 (hexanal), 8.91x10-6to 1.94 (acetone), 6.74x10-1to 2.24 (benzaldehyde). The amount of generated volatile compounds increased astheroasting temperature and time increased. The consumer acceptability test revealed that samples roasted for 40 or 60 min at 140°C produced the most acceptable product in terms of all the measured attributes. The study showed that the roasting conditions produced acceptable cashew kernelsof desirable colour and superior flavour quality that enhance direct and commercial utilization.

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