Gas Chromatographic Determination of Propamocarb in Agricultural Commodities

1996 ◽  
Vol 79 (3) ◽  
pp. 769-772 ◽  
Author(s):  
Toshihiro Nagayama ◽  
Maki Kobayashi ◽  
Hiroko Shioda ◽  
Toshio Tomomatsu
Keyword(s):  
Detection Limit ◽  
Diethyl Ether ◽  
Signal To Noise Ratio ◽  
Chromatographic Determination ◽  
Agricultural Commodities ◽  
Signal To Noise ◽  
Aqueous Fraction ◽  
Acetone Water ◽  
Nitrogen Phosphorus

Abstract A simple and efficient gas chromatographic (GC) method is described for quantitative determination of propamocarb in agricultural commodities. Propamocarb is extracted into acetone–water (or acidified solvent for dry products) and then cleaned up by extraction with diethyl ether. The analyte is extracted from the aqueous fraction under basic conditions with diethyl ether and then analyzed by GC with nitrogen–phosphorus detection. The minimum detection limit is 0.01 μg/g in original samples (signal-to-noise ratio > 5). Recovery of propamocarb spiked at 0.1 μg/g into various samples is >75%, except for lettuce (41%).

Ion-chromatographic determination of plasma oxalate reexamined

1993 ◽  
Vol 39 (3) ◽  
pp. 537-539 ◽  
Author(s):  
M Petrarulo ◽  
E Cerelli ◽  
M Marangella ◽  
F Maglienti ◽  
F Linari
Keyword(s):  
Detection Limit ◽  
Hydrochloric Acid ◽  
Signal To Noise Ratio ◽  
Sample Pretreatment ◽  
Chromatographic Determination ◽  
Plasma Samples ◽  
Signal To Noise ◽  
Analytical Recovery ◽  
Healthy Persons

Abstract This new procedure for determining oxalic acid in plasma is based on sample deproteinization with hydrochloric acid and acetonitrile and subsequent ion-chromatographic assay of the neutralized supernate. Sample pretreatment produces very clean samples, which ensures long column life. Mean analytical recovery of oxalate (5.0-10.0 mumol/L) added to plasma samples averaged 98.6 +/- 6.2%; imprecision (CV) was 5.2% (at 2.2 mumol/L) and the detection limit was 0.5 mumol/L at a signal-to-noise ratio of 5:1. Ascorbate to oxalate conversion was < 0.2%, indicating that the procedure is free from ascorbate interference. Plasma oxalate concentrations, measured in samples from 31 healthy persons, ranged from 0.8 to 3.4 mumol/L (mean 1.89, SD 0.75 mumol/L), which agrees with results from indirect radioisotopic dilution methods.

Ion-chromatographic determination of L-tartrate in urine samples

1991 ◽  
Vol 37 (1) ◽  
pp. 90-93 ◽  
Author(s):  
Mlchele Petrarulo ◽  
Martino Marangella ◽  
Omalla Bianco ◽  
Franco Linari
Keyword(s):  
Potential Role ◽  
Signal To Noise Ratio ◽  
Standard Procedure ◽  
Dicarboxylic Acids ◽  
Chromatographic Determination ◽  
Signal To Noise ◽  
Coefficients Of Variation ◽  
Analytical Recovery

Abstract We propose using ion chromatography to determine tartrate concentration in urine. A 100-microL sample of urine is diluted and injected into the chromatograph. Tartrate is eluted within 11.5 min as a distinct and well-resolved peak. The sensitivity of the standard procedure (signal-to-noise ratio, 3/1) is 30 mumol/L. The intra-run and interrun coefficients of variation are 2.5% and 4.1%, respectively. Mean analytical recovery of known amounts of added tartrate ranges between 94.2% and 104.0%. We investigated the specificity of the procedure by analyzing urine containing added dicarboxylic acids structurally related to tartrate. The reliability of the procedure makes it suitable for investigating tartrate metabolism, e.g., the potential role of tartrate as an inhibitor of crystallization in calcium nephrolithiasis.

scholarly journals METHODOLOGICAL RECEPTION FOR DETERMINATION OF DICAMBA RESIDUES IN SOYBEANS BY GC-MS

2018 ◽  
Vol 97 (6) ◽  
pp. 564-567
Author(s):  
Olga E. Egorchenkova ◽  
D. N. Sobolev
Keyword(s):  
Methyl Ester ◽  
Diethyl Ether ◽  
Signal To Noise Ratio ◽  
Gas Liquid Chromatography ◽  
Acetone Water ◽  
Quadratic Deviation ◽  
Chromatographic Measurement ◽  
Development And Validation ◽  
Butyl Methyl Ether

Introduction. In this paper, there are presented results of investigations on the development and validation of the method for the determination of dicamba residues in import foodstuff (soybeans). The identification and quantitative determination of dicamba are performed by capillary gas-liquid chromatography with mass-selective detection (ionization-electron impact). Material and methods. The stages of sample preparation include four steps as extraction with acidified acetonitrile, followed by the filtration and evaporation; freezing the sample with filtration and evaporation; dissolving the dry residue in a mixture of acetone: water (1:20); purification by repeated redistribution in a system of immiscible solvents under varying the pH of the aqueous medium (pH 9-10: dichloromethane, hexane, pH 2: hexane-tert-butyl methyl ether). The chromatographic measurement was preceded by the derivatization of the acid to the corresponding methyl ester by the treatment with a solution of diazomethane in diethyl ether Results. The lower limit of the quantitative evaluation of dicamba in samples of soybean beans is of 0.01 mg/kg, the signal-to-noise ratio at the detection limit accounts of 20:1. The completeness of extraction of dicamba, established on the basis of analysis of model samples with the introduction of a substance at four points within the defined range, amounted to 85-95%. The average quadratic deviation of the repetition varies in the range of 3.3-4.9%. Discussion. The use of diethyl ether containing dibutylhydroxytoluene (6 ppm) as a stabilizer, as well as the interfering effect of phthalates, led to the formation of poorly resolved peaks of the methyl ester of dicamba, dibutylhydroxytoluene, and dibutyl phthalate. The combination of the use of different methods of data collection (in the scanning mode and in the mode of recording individual ions) made it possible to identify these components. Replacement of the used diethyl ether, as well as variation of chromatographic conditions, for separation of dicamba and phthalate peaks, made it possible to achieve the necessary selectivity of detection of the analyte.

Determination of Phthalate Esters in Plastic Track Surface Layer Material by Gas Chromatography

2017 ◽  
Vol 726 ◽  
pp. 43-49 ◽  
Author(s):  
Peng Chen ◽  
Dan Hua Xu ◽  
Qing Dan Yuan ◽  
Shi Hua Liu
Keyword(s):  
Gas Chromatography ◽  
Surface Layer ◽  
Detection Limit ◽  
Signal To Noise Ratio ◽  
Phthalate Esters ◽  
Microwave Extraction ◽  
Signal To Noise ◽  
Layer Material ◽  
Track Surface

A method was proposed to simultaneously and rapidly determine the content of five kinds of phthalate esters (DMP, DBP, BBP, DnHP, DOP) in plastic track surface layer material by gas chromatography (GC) with the external standard,and the method was first proposed. The sample pretreatment method was microwave-assisted extracted using ethyl acetate as the solvent. Discussed the effects of extraction conditions on the extraction efficiency, microwave extraction time was 30 minutes, microwave extraction temperature was 100°C,the volume of ethyl acetate was 15mL. The results showed that there was a good linear relationship in range of 0.040 to 50 mg/L(R2 was 0.9987-0.9994). The average recoveries of standard addition for five kinds of phthalate esters were between 83.83% and 101.02%, and the relative standard derivations (RSDs (n=6)) ranged from 0.95% to 4.73%. The three times of signal to noise ratio (3 S/N) was used to calculate the detection limit of the method , and the detection limit was 2.5-3.0 mg/kg. The ten times of signal to noise ratio (10 S/N) was used to calculate the quantitation limit of the method, and the limit of quantitation was 8.5-10 mg/kg. This method is simple, effective and suitable for the determination of phthalate esters in plastic track surface layer material.

Determination of the Best Emulsion for the Microscopy of Crystals

1981 ◽  
Vol 39 ◽  
pp. 32-33
Author(s):  
David A. Grano ◽  
Kenneth H. Downing
Keyword(s):  
Spatial Frequency ◽  
Information Transfer ◽  
Signal To Noise Ratio ◽  
Experimental Situation ◽  
Photographic Emulsion ◽  
Modulation Transfer ◽  
Signal To Noise ◽  
Frequency Space ◽  
Noise Ratio

The retrieval of high-resolution information from images of biological crystals depends, in part, on the use of the correct photographic emulsion. We have been investigating the information transfer properties of twelve emulsions with a view toward 1) characterizing the emulsions by a few, measurable quantities, and 2) identifying the “best” emulsion of those we have studied for use in any given experimental situation. Because our interests lie in the examination of crystalline specimens, we've chosen to evaluate an emulsion's signal-to-noise ratio (SNR) as a function of spatial frequency and use this as our critereon for determining the best emulsion.The signal-to-noise ratio in frequency space depends on several factors. First, the signal depends on the speed of the emulsion and its modulation transfer function (MTF). By procedures outlined in, MTF's have been found for all the emulsions tested and can be fit by an analytic expression 1/(1+(S/S0)2). Figure 1 shows the experimental data and fitted curve for an emulsion with a better than average MTF. A single parameter, the spatial frequency at which the transfer falls to 50% (S0), characterizes this curve.

Improved Cleanup and Derivatization for Gas Chromatographic Determination of Monosodium Glutamate in Foods

1983 ◽  
Vol 66 (6) ◽  
pp. 1528-1531 ◽  
Author(s):  
Hiroshi Nakanishi
Keyword(s):  
Glutamic Acid ◽  
Acid Derivative ◽  
Monosodium Glutamate ◽  
Chromatographic Determination ◽  
Flame Ionization Detection ◽  
Gas Chromatograph ◽  
Flame Ionization ◽  
Acetone Water ◽  
Chromatographic Procedure

Abstract A gas chromatographic procedure is described for determining monosodium glutamate (MSG) in several types of food. A sample is extracted with acetone- water (1 + 1). Acetone is evaporated and an aliquot of the extract is buffered with 1M NH4OH-1M NH4CI pH 9 solution, and chromatographed directly on a column of QAE Sephadex A-25 that has been pretreated with the same buffer. MSG is eluted with 0.1N HC1, and a portion of the eluate is evaporated to dryness and reacted with dimethylformamide( DMF)-dimethylacetal to form the glutamic acid derivative, which is injected into a gas chromatograph and measured by flame ionization detection. Recoveries of MSG from sample fortified at 5-500 mg ranged from 92.8 to 100%.

scholarly journals Remote whispering metamaterial for non-radiative transceiving of ultra-weak sound

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jin Zhang ◽  
Wei Rui ◽  
Chengrong Ma ◽  
Ying Cheng ◽  
Xiaojun Liu ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Detection Limit ◽  
Free Space ◽  
Signal To Noise Ratio ◽  
Resonance Energy Transfer ◽  
Information Leakage ◽  
Resonance Energy ◽  
Acoustic Analogy ◽  
Signal To Noise ◽  
Airborne Sound

AbstractTransceiving ultra-weak sound typically relies on signal pre-amplification at the transmitting end via active electro-acoustic devices, which inherently perturbs the environment in the form of noise that inevitably leads to information leakage. Here we demonstrate a passive remote-whispering metamaterial (RWM) enabling weak airborne sound at audible frequencies to reach unprecedented signal enhancement without altering the detected ambient soundscape, which is based on the extraordinary scattering properties of a metamaterial formed by a pair of self-resonating subwavelength Mie meta-cavities, constituting the acoustic analogy of Förster resonance energy transfer. We demonstrate efficient non-radiative sound transfer over distances hundreds times longer than the radius of the meta-cavities, which enables the RWM to recover weak sound signals completely overwhelmed by strong noise with enhanced signal-to-noise ratio from −3 dB below the detection limit of 0 dB in free space to 17.7 dB.

Liquid Chromatographic Determination of Sulfamoyldapsone in Swine Tissues

1987 ◽  
Vol 70 (6) ◽  
pp. 1031-1032
Author(s):  
Yuuko S Endoh ◽  
Ryozo Yamaoka ◽  
Nobuo Sasaki
Keyword(s):  
Detection Limit ◽  
Quantitative Determination ◽  
Chromatographic Determination ◽  
Alumina Column ◽  
Average Recovery ◽  
Diaminodiphenyl Sulfone ◽  
Alumina Column Chromatography ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method is described for the quantitative determination of sulfamoyldapsone (2-sulfamoyl-4,4'-diaminodiphenyl sulfone) in swine muscle, liver, kidney, and fat. Sulfamoyldapsone was extracted from tissues with acetonitrile saturated with n-hexane. The extract was washed with n-hexane saturated with acetonitrile, concentrated, and cleaned up by alumina column chromatography. Sulfamoyldapsone was separated on an ODS column by using acetonitrile-methanol-water (6 + 18 + 76) and was detected at 292 nm. Overall average recovery of sulfamoyldapsone added to tissues at levels of 0.1 and 0.5 /μg/g was 93.3% ± 6.0. Detection limit was 0.02 μg/g in these tissues.

scholarly journals Distance scaling method for accurate prediction of slowly varying magnetic fields in satellite missions

2016 ◽  
Vol 5 (2) ◽  
pp. 281-288 ◽  
Author(s):  
Panagiotis P. Zacharias ◽  
Elpida G. Chatzineofytou ◽  
Sotirios T. Spantideas ◽  
Christos N. Capsalis
Keyword(s):  
Signal To Noise Ratio ◽  
Near Field ◽  
Magnetic Behavior ◽  
Field Measurements ◽  
High Signal ◽  
Signal To Noise ◽  
Scaling Method ◽  
Magnetic Signature ◽  
The Magnetic Field

Abstract. In the present work, the determination of the magnetic behavior of localized magnetic sources from near-field measurements is examined. The distance power law of the magnetic field fall-off is used in various cases to accurately predict the magnetic signature of an equipment under test (EUT) consisting of multiple alternating current (AC) magnetic sources. Therefore, parameters concerning the location of the observation points (magnetometers) are studied towards this scope. The results clearly show that these parameters are independent of the EUT's size and layout. Additionally, the techniques developed in the present study enable the placing of the magnetometers close to the EUT, thus achieving high signal-to-noise ratio (SNR). Finally, the proposed method is verified by real measurements, using a mobile phone as an EUT.

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