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.

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%.

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.

Gas Chromatographic Determination of the Plant Growth Regulator Flurprimidol in Soil and Soil-Grass Samples

1986 ◽  
Vol 69 (4) ◽  
pp. 572-575
Author(s):  
Sheldon D West ◽  
Bonnie S Rutherford
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Detection Limit ◽  
Plant Growth ◽  
Plant Growth Regulator ◽  
Chromatographic Determination ◽  
Gas Chromatography Mass Spectrometry ◽  
Electron Capture Detection ◽  
Control Samples

Abstract A method is described for the determination of flurprimidol residues in soil and soil-grass samples. Flurprimidol is extracted from the sample by refluxing with methanol-water. An aliquot is partitioned into hexane and purified by alumina B Sep-Pak column chromatography. The compound is detected and measured by gas chromatography with electron capture detection. Residue identity is confirmed by gas chromatography-mass spectrometry with detection at m/z 269.0. The detection limit is 0.01 ppm, and recoveries for control samples fortified with flurprimidol at 0.01-2.0 ppm averaged 80% for soil and 78% for soil-grass samples.

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.

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 Conditioning Treatments Affect Insect and Mite Populations on Bedding Plants in the Greenhouse

HortScience ◽  
1999 ◽  
Vol 34 (2) ◽  
pp. 235-238 ◽  
Author(s):  
Joyce G. Latimer ◽  
Ronald D. Oetting
Keyword(s):  
Frankliniella Occidentalis ◽  
Western Flower Thrips ◽  
New Guinea ◽  
Moisture Stress ◽  
Greenhouse Production ◽  
Dioic Acid ◽  
Stress Conditioning ◽  
New Guinea Impatiens ◽  
Aphid Populations ◽  
Ebb And Flow

During greenhouse production in Spring 1995, conditioning treatments were applied to columbine (Aquilegia×hybrida Sims `McKana Giants'), New Guinea impatiens (Impatiens hawkeri Bull. `Antares'), marigold (Tagetes erecta L. `Little Devil Mix') and ageratum (Ageratum houstonianum Mill. `Blue Puffs') plants. Treatments included: mechanical conditioning (brushing 40 strokes twice daily); moisture stress conditioning (MSC) (wilting for ≈2 hours per day); undisturbed ebb-and-flow irrigation; overhead irrigation; high (500 mg·L-1 N) or low (50 mg·L-1 N) 3×/week N fertilizer regimes; daminozide (5000 mg·L-1); or paclobutrazol (30, 45, or 180 mg·L-1). One week after initiation of treatments, individual plants in separate greenhouses were inoculated with two adult green peach aphids (Myzus persicae Sulzer) or five two-spotted spider mites (Tetranychus urticae Koch). A natural infestation of western flower thrips (Frankliniella occidentalis Pergande) in the mite-inoculated greenhouse provided an additional insect treatment. Brushing was the only treatment that consistently reduced thrips and mite populations. Aphid populations were lower on low-N than on high-N plants, but thrips and mite populations were not consistently affected by plant fertilization. Moisture stress conditioning tended to increase aphid populations on New Guinea impatiens and marigold, but had little effect on spider mite or thrips populations. Ebb-and-flow irrigation reduced the mite population on ageratum relative to that on overhead irrigated (control) plants. Plant growth regulators did not consistently affect pest populations. Chemical names used: butane-dioic acid mono(2,2-dimethylhydrazide) (daminozide); β-[(4-chlorophenyl)methyl]-α-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-1-ethanol (paclobutrazol).

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