Determination of the aqueous-phase structure of 6-O-methylerythromycin from NMR constraints

2001 ◽  
Vol 39 (4) ◽  
pp. 163-172 ◽  
Author(s):  
Wayne E. Steinmetz ◽  
Jack D. Sadowsky ◽  
Jeffrey S. Rice ◽  
John J. Roberts ◽  
Yen K. Bui
Keyword(s):  
Aqueous Phase ◽  
Phase Structure

Determination of Dimetridazole and Ipronidazole in Feeds at Cross-Contamination Levels

1988 ◽  
Vol 71 (3) ◽  
pp. 474-477 ◽  
Author(s):  
Duane D Hughes
Keyword(s):  
Thin Layer ◽  
Rapid Method ◽  
Aqueous Phase ◽  
Borate Buffer ◽  
Cross Contamination ◽  
Chromatographic System ◽  
Arsanilic Acid ◽  
Contamination Levels ◽  
Benzene Extract

Abstract A rapid method for the determination of dimetridazole and ipronidazole in feeds is described. The compounds are extracted from a borate buffer (pH 8.65) with benzene, partitioned into IN HC1, and then partitioned back into benzene from a basic aqueous phase. The benzene extract is concentrated and injected onto a nonpolar (Apiezon L) gas chromatographic column for determination by 63Ni electroncapture detection. Recoveries from feeds of various composition, spiked at 0.2 ppm with both dimetridazole and ipronidazole, ranged from 70 to 115%; for the same feeds spiked at 1 ppm or more, the recoveries were greater than 80%. Carbadox, furazolidone, levamisole, oxytetracycline, chlortetracycline, sulfamethazine, sulfaquinoxaline, arsanilic acid, piperazine, penicillin, and commonly added vitamins and minerals do not interfere. A 2-dimensional thin layer chromatographic system is presented as a means of additional identification.

HPLC Determination of Furfural after Preliminary Extraction to Aqueous Phase

2007 ◽  
Vol 30 (14) ◽  
pp. 2081-2093 ◽  
Author(s):  
Hossein Sid Kalal ◽  
Mohamad Khayatzadeh Mahani ◽  
Mohamad Ghanadi Maragheh ◽  
Marzieh Chaloosi
Keyword(s):  
Aqueous Phase ◽  
Hplc Determination ◽  
Preliminary Extraction

Determination of Tin in Canned Fruits and Vegetables by Atomic Absorption Spectrometry and Liquid–Liquid Extraction

1994 ◽  
Vol 77 (6) ◽  
pp. 1627-1630 ◽  
Author(s):  
Ana M Martín ◽  
Mercedes Sánchez ◽  
Pedro Espinosa ◽  
Gracia Bagur
Keyword(s):  
Aqueous Phase ◽  
Fruits And Vegetables ◽  
Methyl Ketone ◽  
Absorption Spectrometry ◽  
Liquid Extraction ◽  
Acid Complex ◽  
Liquid Liquid Extraction ◽  
Relative Standard ◽  
Good Agreement

Abstract A method was developed for the determination of tin based on the extraction of its 5,5-methylenedisalicylohydroxamic acid complex with 1.09M isobutyl methyl ketone in tributyl phosphate. After the samples were treated with nitric and hydrochloric acid, the aqueous phase was made to 0.05M in perchloric acid. When the ratio of aqueous phase to organic phase was 4:1 (v/v), the detection limit and the relative standard deviation (n = 7,50 μg tin) were 0.20 μg/mL and 0.9%, respectively. The proposed method was applied to the analysis of tin in canned fruits and vegetables. The results were in good agreement with those obtained by the phenylfluorone method.

Determination of unconjugated 3-methoxy-4-hydroxyphenylglycol by liquid chromatography for monitoring inhibition of monoamine oxidase activity in plasma.

1987 ◽  
Vol 33 (11) ◽  
pp. 2078-2080 ◽  
Author(s):  
R N Gupta ◽  
M Steiner ◽  
M Lew
Keyword(s):  
Liquid Chromatography ◽  
Monoamine Oxidase ◽  
Ethyl Acetate ◽  
Aqueous Phase ◽  
Oxidase Activity ◽  
Back Extraction ◽  
Monoamine Oxidase Activity ◽  
Simple Method ◽  
Extraction Recovery

Abstract We describe a simple method for extracting 3-methoxy-4-hydroxyphenylglycol (MHPG) from plasma. The sample is applied to a 1-mL "Extrelut" column (EM Industries) and eluted 15 min later with ethyl acetate. After mixing the eluate with pentane and back-extraction into water, we inject 25 or 50 microL of the aqueous phase onto a Beckman 15 cm x 4.6 mm (i.d.) column packed with 5-micron ODS particles (Beckman). Peaks are detected with a coulometric detector. The resulting chromatogram is clean, with few extraneous peaks. The extraction recovery of MHPG is 55-60%, which allows for detection of as little as 0.2 microgram of the analyte per liter. The decrease in the concentration of MHPG in plasma of patients treated with phenelzine agrees with the decrease in monoamine oxidase activity in platelets of these patients.

Determination of Nicotine in Feeds

1964 ◽  
Vol 47 (2) ◽  
pp. 226-228
Author(s):  
David E Root
Keyword(s):  
Aqueous Phase ◽  
Steam Distillation ◽  
Animal Feed ◽  
Collaborative Study ◽  
Basic Solution ◽  
Ultraviolet Spectrophotometry

Abstract Nicotine, used in medicated animal feed in combination with phenothiazine, dibutyl tin dilaurate, and 2,2'-dihydroxy-5,5’-dichlorophenyl methane, has been successfully isolated from these compounds and the feed interferences and cleaned up by extraction with 0.5% NaOH, steam distillation f r om this basic solution, and extraction from the aqueous phase with chloroform. The nicotine is then partitioned into 0.05iV HC1, and determined by ultraviolet spectrophotometry. A collaborative study yielded 9 0% over-all recoveries, and the method is recommended for adoption as official, first action.

scholarly journals Gas-Phase Structure Determination of Dihydroxycarbene, One of the Smallest Stable Singlet Carbenes

2014 ◽  
Vol 126 (16) ◽  
pp. 4173-4176 ◽  
Author(s):  
Caroline C. Womack ◽  
Kyle N. Crabtree ◽  
Laura McCaslin ◽  
Oscar Martinez ◽  
Robert W. Field ◽  
...  
Keyword(s):  
Gas Phase ◽  
Structure Determination ◽  
Phase Structure ◽  
Singlet Carbenes ◽  
Gas Phase Structure
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