scholarly journals New Acyclic Diterpenic Acids from Yacon (Smallanthus Sonchifolius) Leaves

2010 ◽  
Vol 5 (11) ◽  
pp. 1934578X1000501 ◽  
Author(s):  
María I. Mercado ◽  
María V. Coll Aráoz ◽  
Alfredo Grau ◽  
César A. N. Catalán
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Methylene Chloride ◽  
Sesquiterpene Lactones ◽  
2D Nmr ◽  
Smallanthus Sonchifolius

Two new acyclic diterpenoids, smaditerpenic acid E (1a) and F (2a), along with nineteen melampolide-type sesquiterpene lactones, six of them not previously reported in yacon, were isolated from the methylene chloride leaf rinse extract. Their structures were elucidated from 1D and 2D NMR experiments and gas chromatography coupled to mass spectrometry.

Hemopyrrole and kryptopyrrole are absent from the urine of schizophrenics and normal persons.

1978 ◽  
Vol 24 (2) ◽  
pp. 230-233 ◽  
Author(s):  
P L Gendler ◽  
H A Duhan ◽  
H Rapoport
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Detection Limit ◽  
Methylene Chloride ◽  
Acute Intermittent Porphyria ◽  
Gas Chromatography Mass Spectrometry ◽  
Chromatography Mass Spectrometry

Abstract We describe a method for detecting hemopyrrole and kryptopyrrole in urine, with a detection limit of 100 mug/liter (1 part in 10(7)). Urine is thoroughly extracted with methylene chloride and the extract is concentrated and examined by gas chromatography and gas chromatography-mass spectrometry. No hemopyrrole or kryptopyrrole could be detected in 52 samples, from 17 controls, 29 schizophrenics, and six persons with acute intermittent porphyria.

Determination and Confirmation of cis-9-Tricosene in Technical Materials by Capillary Gas Chromatography and Gas Chromatography/Mass Spectrometry

1992 ◽  
Vol 75 (5) ◽  
pp. 878-882
Author(s):  
Jinren Ko ◽  
Jack Nguyen ◽  
Jim Burleson
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Correlation Coefficient ◽  
Calibration Curve ◽  
Capillary Gas Chromatography ◽  
Methylene Chloride ◽  
Internal Standard ◽  
Gas Chromatography Mass Spectrometry ◽  
Technical Material ◽  
Standard Calibration

Abstract A capillary gas chromatographic (GC) method was developed for the quantitation of cis-9-tricosene in technical material. This method is capable of resolving cis-9-tricosene from the trans-9-tricosene isomer and other impurities in technical 9-tricosene. Samples are dissolved in methylene chloride and analyzed by splitless GC using docosane as an internal standard. The integrity and purity of the peak of interest were confirmed by GC/mass spectrometry. The overall recovery of this method was 101.3 ± 0.82%. The correlation coefficient of the standard calibration curve was 0.9999. The system and method precision for cis-9-tricosene were 0.18 and 0.20%, respectively. The reproducibility of the method by different analysts was within 0.5%.

scholarly journals Effect of Mechanical and Moisture-stress Conditioning on Growth and Cuticle Composition of Broccoli Transplants

1997 ◽  
Vol 122 (6) ◽  
pp. 788-791 ◽  
Author(s):  
Joyce G. Latimer ◽  
Ray F. Severson
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Plant Growth ◽  
Methylene Chloride ◽  
Moisture Stress ◽  
Epicuticular Waxes ◽  
Greenhouse Production ◽  
Detached Leaves ◽  
Stress Conditioning ◽  
Over Time

Epicuticular waxes were analyzed to explain the visible differences in the waxy bloom of conditioned broccoli (Brassica oleracea L. Group Italica `Green Duke') transplants. Seedlings (22 days old) were subjected to brushing (40 cycles per minute, 1 minute twice daily), wind (7 m·s-1 for 5 minutes twice daily), or moisture-stress conditioning (MSC; visible wilt for 2 to 4 hours daily) for 16 (1987) or 21 (1988) days during transplant production in the greenhouse. The epicuticular waxes of the uppermost fully expanded leaves were removed by dipping detached leaves into methylene chloride. The extract was derivatized with trimethylsilyl reagents and subjected to capillary gas chromatography. The primary epicuticular wax components were the nonpolar C29 compounds nonacosane, nonacosan-15-ol, and nonacosan-15-one, which were identified by mass spectrometry. In a Summer 1987 experiment, cuticle samples taken over time of treatment indicated acclimation to the conditioning treatments relative to untreated plants. After 9 days of treatment, the amount of total epicuticular waxes present on the leaves was reduced 38%, 31%, or 11% by wind, brushing, or MSC, respectively. However, after 15 days of treatment, the amount of cuticle present was reduced 15% by brushing but only 6% by wind and was 17% greater in MSC-treated plants. Two weeks after transplanting to the field there were no differences in the amount or composition of the epicuticular waxes. In Fall 1988, all treatments reduced plant growth, but only MSC tended to increase the amount of C29 epicuticular components during greenhouse production. Differences in the amounts of epicuticular waxes were no longer significant after 8 days in the field.

Capillary Column Gas Chromatographic Determination of Ethyl Carbamate in Alcoholic Beverages with Confirmation by Gas Chromatography/Mass Spectrometry

1987 ◽  
Vol 70 (4) ◽  
pp. 749-751 ◽  
Author(s):  
Henry B S Conacher ◽  
Denis B Page ◽  
Benjamin P Y Lau ◽  
James F Lawrence ◽  
Ruth Bailey ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Capillary Column ◽  
Methylene Chloride ◽  
Ethyl Carbamate ◽  
Mass Spectrometric ◽  
Mass Spectrometric Detection ◽  
Alcoholic Beverages ◽  
Gas Chromatography Mass Spectrometry ◽  
Acetate Solution

Abstract A method is described for determining ethyl carbamate at low \i%l kg levels in several types of alcoholic beverages by capillary column gas chromatography with Hall electrolytic conductivity detection and confirmation by mass spectrometry. Samples are diluted to obtain a uniform concentration of ethanol (ca 10%) then saturated with NaCl and extracted with methylene chloride. Extracts are evaporated to a small volume and injected in ethyl acetate solution for chromatographic analysis. The method was evaluated by 5 laboratories, 4 employing the Hall detector and one using mass spectrometric detection. Overall between-laboratory mean percent recoveries were: wine, 85.3 ± 21.0% coefficient of variation (CV) (spiking level 20- 45 μg/kg); sherry, 83.8 ± 16.1% CV (spiking level, 81-142 μg/kg);whiskey, 79.5 ± 13.9% CV (spiking level 127-190 Mg/kg); and brandy, 85.0 ± 12.5% CV (spiking level 297-446 μg/kg). Mass spectrometric results agreed well with the Hall results for all commodities. Detection limits were about 5 μg/kg for the Hall detector and about 0.5 μg/kg for mass spectrometric detection.

scholarly journals Development and Validation of a Gas Chromatography/Mass Spectrometry Procedure for Confirmation of Para-Toluenesulfonamide in Edible Fish Fillet Tissue

2004 ◽  
Vol 87 (5) ◽  
pp. 1098-1108 ◽  
Author(s):  
Olutosin R Idowu ◽  
Philip J Kijak ◽  
Jeffery R Meinertz ◽  
Larry J Schmidt
Keyword(s):  
Mass Spectrometry ◽  
Aqueous Solution ◽  
Gas Chromatography ◽  
Methylene Chloride ◽  
Fish Tissue ◽  
Gas Chromatography Mass Spectrometry ◽  
Chromatography Mass Spectrometry ◽  
Chloramine T ◽  
Development And Validation ◽  
Edible Fish

Abstract Chloramine-T is a disinfectant being developed as a treatment for bacterial gill disease in cultured fish. As part of the drug approval process, a method is required for the confirmation of chloramine-T residues in edible fish tissue. The marker residue that will be used to determine the depletion of chloramine-T residues from the edible tissue of treated fish is para-toluenesulfonamide (p-TSA), a metabolite of chloramine-T. The development and validation of a procedure for the confirmation of p-TSA is described. Homogenized fish tissue is dried by mixing with anhydrous sodium sulfate, and the mixture is extracted with methylene chloride. The extract is passed through a silica gel solid-phase extraction column, from which p-TSA is subsequently eluted with acetonitrile. The acetonitrile extract is evaporated, and the oily residue is dissolved in hexane. The hexane solution is shaken with fresh acetonitrile. The acetonitrile solution is evaporated and the residue is redissolved in dilute potassium hydroxide solution. The aqueous solution is extracted with methylene chloride to further remove more of the fat co-extractive. The aqueous solution is reacted with pentafluorobenzyl bromide in presence of tetrabutylammonium hydrogensulfate. The resulting di-(pentafluorobenzyl) derivative of p-TSA is analyzed by gas chromatography/mass spectrometry. This method permits the confirmation of p-TSA in edible fish tissue at 20 ppb.

scholarly journals Chemical constituents from Vellozia graminifolia (Velloziaceae)

2004 ◽  
Vol 76 (3) ◽  
pp. 505-518 ◽  
Author(s):  
Alexsandro Branco ◽  
Angelo C. Pinto ◽  
Raimundo Braz Filho
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
High Resolution ◽  
Chemical Constituents ◽  
2D Nmr ◽  
Chemical Transformations ◽  
Pentacyclic Triterpenes ◽  
Labdane Diterpene ◽  
High Resolution Gas Chromatography ◽  
Ethyl Acetate Extracts

From the hexane and ethyl acetate extracts obtained from stems, roots and leaf sheaths of Vellozia graminifolia, a mixture of linear hydrocarbons, a mixture of pentacyclic triterpenes, five monoisoprenylated flavonoids and one labdane diterpene, (-)-ent-3beta-hydroxy-8(17)-labden-15-oic acid, were isolated. The linear hydrocarbons and minor triterpenes were identified in their corresponding mixtures by High Resolution Gas Chromatography (HRGC) and HRGC coupled to mass spectrometry. The major pentacyclic triterpenes and the diterpene were characterized by spectral data, including 2D NMR experiments, and chemical transformations.

scholarly journals Guaianolide Sesquiterpene Lactones from Centaurothamnus maximus

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 2055
Author(s):  
Taha A. Hussien ◽  
Tarik A. Mohamed ◽  
Abdelsamed I. Elshamy ◽  
Mahmoud F. Moustafa ◽  
Hesham R. El-Seedi ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
Biosynthetic Pathway ◽  
Fast Atom Bombardment ◽  
Arabian Peninsula ◽  
Sesquiterpene Lactones ◽  
2D Nmr ◽  
Spectroscopic Techniques ◽  
Chemical Structures ◽  
Aerial Parts

Centaurothamnus maximus (family Asteraceae), is a leafy shrub indigenous to the southwestern Arabian Peninsula. With a paucity of phytochemical data on this species, we set out to chemically characterize the plant. From the aerial parts, two newly identified guaianolides were isolated: 3β-hydroxy-4α(acetoxy)-4β(hydroxymethyl)-8α-(4-hydroxy methacrylate)-1αH,5αH, 6αH-gual-10(14),11(13)-dien-6,12-olide (1) and 15-descarboxy picrolide A (2). Seven previously reported compounds were also isolated: 3β, 4α, 8α-trihydroxy-4-(hydroxymethyl)-lαH, 5αH, 6βH, 7αH-guai-10(14),11(13)-dien-6,12-olide (3), chlorohyssopifolin B (4), cynaropikrin (5), hydroxyjanerin (6), chlorojanerin (7), isorhamnetin (8), and quercetagetin-3,6-dimethyl ether-4’-O-β-d-pyranoglucoside (9). Chemical structures were elucidated using spectroscopic techniques, including High Resolution Fast Atom Bombardment Mass Spectrometry (HR-FAB-MS), 1D NMR; 1H, 13C NMR, Distortionless Enhancement by Polarization Transfer (DEPT), and 2D NMR (1H-1H COSY, HMQC, HMBC) analyses. In addition, a biosynthetic pathway for compounds 1–9 is proposed. The chemotaxonomic significance of the reported sesquiterpenoids and flavonoids considering reports from other Centaurea species is examined.

Capillary Column Gas Chromatographic Determination of Ethyl Carbamate in Alcoholic Beverages with Confirmation by Gas Chromatography/Mass Spectrometry

1987 ◽  
Vol 70 (4) ◽  
pp. 749-751
Author(s):  
Henry B.S. Conacher ◽  
B.Denis Page ◽  
Benjamin P.Y. Lau ◽  
James F. Lawrence ◽  
Ruth Bailey ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Capillary Column ◽  
Methylene Chloride ◽  
Ethyl Carbamate ◽  
Mass Spectrometric ◽  
Mass Spectrometric Detection ◽  
Alcoholic Beverages ◽  
Gas Chromatography Mass Spectrometry ◽  
Acetate Solution

Abstract A method is described for determining ethyl carbamate at low \i%l kg levels in several types of alcoholic beverages by capillary column gas chromatography with Hall electrolytic conductivity detection and confirmation by mass spectrometry. Samples are diluted to obtain a uniform concentration of ethanol (ca 10%) then saturated with NaCl and extracted with methylene chloride. Extracts are evaporated to a small volume and injected in ethyl acetate solution for chromatographic analysis. The method was evaluated by 5 laboratories, 4 employing the Hall detector and one using mass spectrometric detection. Overall between-laboratory mean percent recoveries were: wine, 85.3 ± 21.0% coefficient of variation (CV) (spiking level 20- 45 μg/kg); sherry, 83.8 ± 16.1% CV (spiking level, 81-142 μg/kg);whiskey, 79.5 ± 13.9% CV (spiking level 127-190 Mg/kg); and brandy, 85.0 ± 12.5% CV (spiking level 297-446 μg/kg). Mass spectrometric results agreed well with the Hall results for all commodities. Detection limits were about 5 μg/kg for the Hall detector and about 0.5 μg/kg for mass spectrometric detection.

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