Organic Functional Group Analysis Research Articles

Study of soil management in rice fields in Bantimurung District Maros Regency

Rice productivity in Bantimurung District is unstable every year. Farmers tend not to attend to environmental and soil protection but are racing to increase yields rapidly using excessive chemical fertilizers and pesticides, tilling the soil too frequently, and burning postharvest straw. This study aims to study rice fields’ management in Bantimurung District, Maros Regency, based on the soil’s physical and chemical characteristics, which are expected to be a source of information in managing rice fields in Bantimurung District, Maros Regency. Data were collected using a field survey method in irrigated and rainfed rice fields and farmer interviews. Laboratory analysis included soil texture, bulk density, N-total, C-organic, pH, and organic functional group analysis. The result showed that both irrigated and rainfed rice fields have the low category of N-total (0.1-0.23%), low to a moderate category of c-organic (1.87-3.16%), and slightly acid to neutral pH (5.98-6.67). Based on farmers’ information, we know that the rice fields in Bantimurung District are still suitable for rice production but must have a proper good management principle. The best management includes not using an-organic fertilizer excessively, adding organic matter, crop rotation, and attending to water needs.

An open platform for Aerosol InfraRed Spectroscopy analysis – AIRSpec

Abstract. AIRSpec is a platform consisting of several chemometric packages developed for analysis of Fourier transform infrared (FTIR) spectra of atmospheric aerosols. The packages are accessible through a browser-based interface, which also generates the necessary input files based on user interactions for provenance management and subsequent use with a command-line interface. The current implementation includes the task of baseline correction, organic functional group (FG) analysis, and multivariate calibration for any analyte with absorption in the mid-infrared. The baseline correction package uses smoothing splines to correct the drift of the baseline of ambient aerosol spectra given the variability in both environmental mixture composition and substrates. The FG analysis is performed by fitting individual Gaussian line shapes for alcohol (aCOH), carboxylic acid (COOH), alkane (aCH), carbonyl (CO), primary amine (aNH2), and ammonium (ammNH) for each spectrum. The multivariate calibration model uses the spectra to estimate the concentration of relevant target variables (e.g., organic or elemental carbon) measured with different reference instruments. In each of these analyses, AIRSpec receives spectra and user choices on parameters for model computation; input files with parameters that can later be used with a command-line interface for batch computation are returned together with diagnostic figures and tables in text format. AIRSpec is built using the open-source software consisting of R and Shiny and is released under the GNU Public License v3. Users can download, modify, and extend the package, or access its functionality through the web application (http://airspec.epfl.ch, last access: 3 April 2019) hosted at the École polytechnique fédérale de Lausanne (EPFL). AIRSpec provides a unified framework by which different chemometric techniques can be shared and accessed, and its underlying suite of packages provides the basic functionality for extending the platform with new types of analyses. For example, basic functionality includes operations for populating and accessing spectra residing in in-memory arrays or relational databases, input and output of spectra and results of computation, and user interface development. Moreover, AIRSpec facilitates the exploratory work, can be used by FTIR spectra acquired with different methods, and can be extended easily with new chemometric packages when they become available. Therefore AIRSpec provides a framework for centralizing and disseminating such algorithms. This paper describes the modular architecture and provides examples of the implemented packages using the spectra of aerosol samples collected on PM2.5 polytetrafluoroethylene (Teflon) filters.

Organic Functional Group Analysis and Drug Stability

Organic Functional Group Analysis and Drug Stability

Application of some reagents used in organic functional group analysis for identification of amines, alcohols, aldehydes and ketones to elimination of these substances from organic mixtures in reaction gas chromatography

A number of reagents have been tested for elimination of lower aliphatic amines and alcohols from mixtures of organic compounds, viz. 4-toluenesulphonyl chloride, 3,5-dinitrobenzoyl chloride, N,N-dimethyl-4'-aminoazobenzene-4-carboxylic acid chloride, 3-nitrophthalic anhydride, phthalic anhydride, N,N-dimethyl-4-aminobenzaldehyde and 1-naphthyl isocyanate. Aldehydes and ketones have been eliminated with 2,4-dinitrophenylhydrazine or 4-nitrophenylhydrazine in the presence of phosphoric acid. The reaction column was placed in the thermostat along with the chromatographic column. The reagents were introduced on Celite 545 or Chromaton N.

Ion-selective electrodes in organic functional group analysis: Microdetermination of hydrazines with the copper electrode

A simple micromethod is described for the determination of hydrazines using the copper ion-selective electrode. The method is based on direct potentiometric titration of the sample in ammoniacal solution of pH 9.5±0.2 with copper(II) ions at room temperature. N-Shaped curves with well-defined inflections at 1∶1 and 1∶2 molar ratios are obtained. This is probably due to the formation of copper monohydrazinate and copper dihydrazinate complexes. Various alkyl and aryl hydrazines and hydrazine salts have been satisfactorily analyzed with an average recovery of 99.4% and a relative standard deviation of ±0.4%. The reaction of hydrazines with Fehling's solution followed by measuring the copper(I) oxide formed using the copper ion-selective electrode also has been investigated.

Ion-selective electrodes in organic functional group analysis: Microdetermination of quinones with Halide electrodes and Gran's plot

Simple and selective methods for the microdetermination ofp-benzoquinones are described. Quinones are reacted with sodium chloride or sodium bromide in 18N sulphuric acid followed by potentiometric titration of the residual excess halide ion with silver nitrate using the chloride or bromide electrode and Gran's plot. The average recovery is 98%. These procedures are not applicable to the determination of fully substituted quinones. Iodometric determination of quinones, after reaction with KI and H2SO4, by titration of the liberated iodine with sodium thiosulphate using the platinum/iodide electrode system is also described. Quinones substituted with electron-repelling groups require sulphonation prior to their determination. The average recovery is 99%.

Ion-selective electrodes in organic functional group analysis: Micro- and submicro-determination of thiocarbonyl and thiol groups using the silver/sulphide and iodide electrodes

Thiocarbonyl and thiol groups in organic compounds are determined by reaction with 1N iodine in carbon tetrachloride in the presence of pyridine, whereby 4 equivalents and 1 equivalent of iodide ion are quantitatively released per group, respectively. The iodide ions in an aqueous extract are potentiometrically titrated with silver nitrate using the solid-state silver/sulphide selective electrode. The results obtained with samples down to 70μg show an average recovery of 98.6% and no interferences are caused by unsaturated functions. Measurement of the iodide ion using the iodide ion-selective electrode and the known addition technique gives results with an absolute error of 2%.

Organic functional group analysis at the micromole level. II

Organic functional group analysis at the micromole level. II

Organic functional group analysis at the micromole level. I

The N-oxides of pyridine and of its homologs and cyano, nitro and halogenated derivatives have been studied by differential pulse polarography. The sensitivity is approximately 0.5μg/ml. Thus analysis of these compounds at theμmol level based on the N-oxide function is feasible.

Ion-selective electrodes in organic functional group analysis: Microdetermination of the amino group using the chloride electrode

Ion-selective electrodes in organic functional group analysis: Microdetermination of the amino group using the chloride electrode

Organic functional group analysis via gas chromatography. III

Organic functional group analysis via gas chromatography. III

Organic Functional Group Analysis & Organic Functional Group Analysis—Theory and Development

Organic Functional Group Analysis & Organic Functional Group Analysis—Theory and Development

Periodate Oxidations

Periodate Oxidation of Diol and other Functional Groups Analytical and Structural Applications. By Glenn Dryhurst. (Monographs in Organic Functional Group Analysis, Vol. 2.) Pp. xii + 191. (Pergamon: Oxford, London and New York, March 1970.) 70s; $9.50.

Peroxide Reactions

The Determination of Organic Peroxides By R. M. Johnson and I. W. Siddiqi. (Monographs in Organic Functional Group Analysis, Vol. 4.) Pp. ix + 119. (Pergamon Press: Oxford, London and New York, 1970.) 50s; $6.75.

Organic Functional Group Analysis by Micro and Semimicro Methods.

Organic Functional Group Analysis by Micro and Semimicro Methods.

Organic functional group analysis via gas chromatography. II

The determination of alkoxyl and alkimino groups has been extended to compounds which produce from methyl to hexyl iodide on treatment with hydriodic acid. An apparatus is described for the decomposition and collection of the alkyl iodides, followed by gas Chromatographic separation and determination on the 0.1 milliequivalent scale. Single compounds and mixtures containing both alkoxyl and alkimino groups have been successfully analyzed.

Microcalorimetric titrations and injection enthalpimetry

In ideal solutions, the temperature change produced by a chemical reaction in an adiabatic environment is solely a function of the relevant concentrations and independent of the volume of the sample taken for analysis This remarkable invariance is due to a compensatory effect between the integral heat evolved (or absorbed) and the heat capacity. Consequently, calorimetric methods are suited par excellence to microanalytical applications. Two alternative methodological approaches are described for the quantitative determination of inorganic materials and for organic functional group analysis, amenable to analyzing as little as 1 μmole of an unknown with a precision and accuracy of 1%, at millimolar concentration levels. Microcalorimetric titrimetry is an end-point determinative technique, utilizing breaks in automatically recorded plots of temperature versus volume of reagent added. “Injection enthalpimetry” relies on the measurement of a “heat pulse” which is proportional to the concentration of the relevant unknown. Temperature changes were determined with the aid of a semi-conductor resistance thermometer circuit, which had the sensitivity of a thousand-junction thermocouple.

Organic functional group analysis by micro and semimicro methods (Cheronis, Nicholas D.)

Organic functional group analysis by micro and semimicro methods (Cheronis, Nicholas D.)

Organic Functional Group Analysis by Micro and Semimicro Methods.

Organic Functional Group Analysis by Micro and Semimicro Methods.

Organic functional group analysis via gas chromatography. I. Microdetermination of carboxyl groups

A gas-chromatographic procedure for the microdetermination of carboxyl groups by decarboxylation is described. The sample is heated in the presence of quinoline and cupric carbonate in a closed vessel; the carbon dioxide formed is then driven into the gas chromatograph. The peak-height on the chromatogram varies linearly with the amount of carboxylic acid in the sample. The method is rapid, simple, and accurate.