Analysis Of Mono Research Articles

Analysis of mono- and disaccharides in milk-based formulae by high-performance liquid chromatography with refractive index detection

A simple and reproducible method for the qualitative and quantitative analysis of free mono- and disaccharides (fructose, glucose, galactose, sucrose, lactulose and lactose) in milk-based formulae by high-performance liquid chromatography (HPLC) with refractive index (RI) detection was developed and validated. The method showed good linearity with determination coefficients exceeding 0.99. The limits of detection (DL) in these sugars were 0.17, 0.13, 0.06, 0.16, 0.05 and 0.25 mg/ml, respectively; and the limits of quantification (QL), 0.27, 0.24, 0.20, 0.26, 0.22 and 0.38 mg/ml. The relative standard deviations (R.S.D.s) for repeatability in fructose, sucrose, lactulose and lactose were 0.78, 0.99, 2.91 and 0.46 and the R.S.D.s for reproducibility were 4.8, 6.15, 7.04 and 2.49, respectively. Recoveries in all sugars were between 93 and 113%.

Analysis of mono- and diesters of o-phthalic acid by solid-phase extractions with polystyrene–divinylbenzene-based polymers

Retention mechanisms of an unmodified and a hydroxylated polystyrene–divinylbenzene polymer were studied by solid-phase extraction of o-phthalic acid and some of its mono- and diesters from purified water and then analysing by GC–MS. The monoesters and phthalic acid were retained only when protonated (i.e. acidified with HCl to pH 0.9). Of all elution solvents tested, ethyl acetate gave the best overall recoveries (61–89%) with both polymers. Applicability to complex matrixes (e.g. acidogenic landfill leachates) was examined by introducing a washing step with acetone in acidified water (pH 0.9) to eliminate volatile fatty acids (C 2–C 6) from the cartridge. Finally, the method was tested on real samples.

Analysis of mono- to deca-brominated diphenyl ethers in chickens at the part per billion level

Polybrominated diphenyl ethers (PBDEs) are flame retardants which have been found to be increasing in the environment. Because of structural similarities to the polychlorinated biphenyls and concerns that PBDEs may be widespread, we have investigated their presence in a food source, namely chickens. A GC–MS method was developed to analyze mono- through deca-BDEs in chicken fat samples. The method utilized GC pressure programming and selected ion monitoring to quantitate PBDEs at the low part per billion level. Four 13 C-labeled surrogates were used to determine recoveries; recoveries averaged from 76% to 114%. Thirteen chickens from the Southern US and a composite sample of chickens from North Dakota were analyzed by this method. The total concentrations of PBDEs on a whole weight basis ranged from 1.7 ppb in North Dakota chickens to 39.4 ppb in a chicken from Arkansas. On a lipid weight basis, these levels were lower than those generally found in fish and fish-eating mammals. The PBDE pattern was also different from other samples reported; penta-BDEs rather than tetra-BDEs were the most prominent congeners.

Analysis of mono- and oligosaccharides by multiwavelength surface plasmon resonance (SPR) spectroscopy

Surface plasmon resonance (SPR) spectra of different saccharides were collected using a home-made multiwavelength SPR apparatus. Pentoses, hexoses, disaccharides and a trisaccharide were distinguished from one another according to their SPR spectra collected at the same concentration. The spectra were also used for the quantitation of sugars by exploring the linear relationship between resonance wavelength and solute concentration. The dynamic linear ranges for the determination of glucose, sucrose and raffinose are 0.01–0.2, 0.005–0.1 and 0.0025–0.1 mol/L, respectively. The SPR spectrum of a mixture of two components was investigated. While the experiments have not been carried out, the implications from this work are that the technique would be applicable to mixtures containing more than two components.

P-139. Cytogenetic analysis of mono- and tri-pronucleate zygotes and embryos resulting from ICSI and IVF

P-139. Cytogenetic analysis of mono- and tri-pronucleate zygotes and embryos resulting from ICSI and IVF

Analysis of Mono- and Oligosaccharide Isomers Derivatized with 9-Aminopyrene-1,4,6-trisulfonate by Capillary Electrophoresis with Laser-Induced Fluorescence

A method of analysis of isomers of mono- and oligosaccharides derivatized with 9-aminopyrene-1,4,6-trisulfonate (APTS) by capillary electrophoresis (CE) in simple buffer systems is presented. The derivatization chemistry is performed at 75°C for 1 h for most mono- and oligosaccharides. Sialyllactose was derivatized at 37°C for 15 h without significant desialylation. Most of the APTS derivatized isomers of mono- and oligosaccharides are resolved in buffers such as acetate (pH 5.0), 3-( N-morpholino)-propanesulfonic acid (pH 7.0), and phosphate (pH 7.4). The mechanism of CE separation using the above buffers is based on the differences in hydrodynamic volume of the derivatized species and is different from that in borate or high pH buffer.

Extraction of mono- and dicarboxylic acids from a curative water.

A method for the analysis of mono- and dicarboxylic acids from water is presented. For this purpose two techniques, a C(18) solid phase extraction (SPE) and a combination method of liquid-liquid extraction (LLE) and aminopropyl SPE, were tested. With the combination method all analytes, short-chain mono- and long-chain dicarboxylic acids, could be analysed in one approach. The C(18) SPE was not suitable for short-chain mono- but for dicarboxylic acids. Concentrations in the investigated water ranged from 315 mg/l (butanoic acid) to 2.9 mg/l (octanoic acid). Dicarboxylic acids were found from 5 mg/l (octanedioic acid) to 0.5 mg/l (dodecanedioic acid).

Analysis of finite-energy signals higher-order moments- and spectra-based time-frequency distributions

A general class of higher-order moments- and spectra-based time-frequency distributions, including Wigner higher-order moment spectra (WHOS), has been defined and studied recently as an extension of bilinear time-frequency representations (TFR) in terms of multilinear (higher than two) moments of the signal. In this paper, the analysis of mono- and multi-component signals is addressed using higher-order TFR. A computationally feasible implementation of the Wigner bispectrum and trispectrum (i.e., WHOS in the third- and fourth-order domains) is proposed considering two-dimensional slices of the time-multifrequency domain of support of WHOS. It is shown that these simplified formulations provide us with information about the evolution of higher-order spectra of a signal with similar resolution and complexity as bilinear TFRs. The problem of cross-terms cancellation is also considered by defining reduced interference distributions as extensions of the Choi-Williams distribution in the fourth-order domain. A simplified implementation, that employs only the principal slice of WHOS, is also proposed for practical purposes. Vor kurzem wurde eine allgemeine Klasse von Momenten höherer Ordnung und Spektrum-basierten Zeit-Frequenz-Verteilungen definiert und untersucht, die Wigner-Spektren höherer Ordnung einschließen und eine Erweiterung von bilinearen Zeit-Frequenz-Darstellungen (TFR) in Abhängigkeit von multilinearen (mehr als zwei) Momenten des Signals darstellen. In dieser Arbeit wird eine Analyse von Mono- und Multikomponenten Signalen unter Anwendung der TFR höherer Ordnung behandelt. Es wird eine rechentechnisch durchführbare Implementierung des Wigner Bispektrums und Trispektrum (d.h. WHOS im Bereich dritter und vierter Ordnung) vorgeschlagen, wobei zweidimensionale Unterräume des Zeit-Multifrequenzbereichs von WHOS betrachtet werden. Es wird gezeigt, daß diese vereinfachten Formulierungen uns Informationen über die Entwicklung von Spektren höherer Ordnung von einem Signal mit gleicher Auflösung und Komplexität wie bilineare TFRs liefern. Das Problem der Auslöschung von Kreuztermen wird auch betrachtet, indem reduzierte Interferenz-Verteilungen wie Erweiterungen der Choi-Williams-Verteilungen auf den Bereich vierter Ordnung definiert werden. Eine vereinfachte Implementierung, welche nur die Haupt-Slices von WHOS berücksichtigt, wird für die praktische Anwendung vorgeschlagen. Une classe de représentations temps-fréquences basées sur les spectres d'ordre supérieur, comprenant les spectres de moment d'ordre supérieur de Wigner (WHOS en anglais), a été récemment définie et étudiée comme une extension des distributions temps-fréquences (TFR) bilinéaires en termes de moments d'ordre supérieur multilinéaires (au delà de l'ordre deux) du signal. Dans cet article, l'analyse des signaux mono et multi-composantes est faite à l'aide de distributions temps-fréquences basées sur les spectres d'ordre supérieur. Dans un premier temps, une implémentation réalisable du calcul des Bispectre et Trispectre de Wigner (c.a.d. WHOS d'ordre trois et quatre) est proposée en ne considérant qu'une tranche bidimensionnelle de l'espace temps-multifréquence du WHOS. Nous montrerons alors que cette formulation simplifiée permet d'obtenir des informations relative au spectre d'ordre supérieur du signal avec une résolution dans le domaine temps-fréquence et une complexité de calcul comparable à celles des TFR bilinéairs. Le problème de l'élimination des termes croisés est alors considéré et des distributions à interférences réduites sont définies comme une extension des distributions de Choi-Williams dans le cas de l'ordre quatre. Une implémentation simplifiée, n'utilisant que la tranche principale du WHOS, est également proposée dans un but pratique.

The Analysis of Mono- and Divalent Cations Present in Explosive Residues Using Ion Chromatography with Conductivity Detection

Abstract The separation of nine mono- and divalent cations of interest in explosives residue analysis was achieved using a Waters IC Pak-C Cation M/D column with a 3 mN HNO3 eluent and conductivity detection. The apparatus was then used to collect data on the types of cations found in a variety of explosive residues including black powder, smokeless powder, and ammonium nitrate based explosives.

Analysis of Mono- and Disaccharides in Indonesian Palm Sugars by a High-Performance Liquid Chromatographic Method

Un support pour chromatographie en phase inverse est adsorbe sur silice et place dans un module de compression radiale. La methode est utilisee pour la separation des glucides dans le sucre de palme et pour etudier la degradation des glucides dans la seve de palme (Arenga pinnata Merr.)

Thermal analysis of ethylenediamine complexes of Ni(II) chloride

Thermal analysis of mono-, bis- and trisethylenediamine (en) complexes of Ni(II) chloride was carried out using TG, DTG and DTA techniques. The kinetic parameters were estimated from dynamic TG studies using the Coats and Redfern equation. The thermal stability of the metal-ligand (Ni-N) bond in, the complex was found to decrease with increasing Ni∶en ratio. The DTA studies showed that the loss of en was initially endothermic but became increasingly exothermic with the progress of the decomposition. The final step in the case of all the three complexes was always composite in nature causing the loss of both Cl atoms with simultaneous oxidation of Ni to NiO. The dissociation of the Ni-en bonds appears to be regulated by the “nucleation and growth” mechanism. Kinetic parameters corresponding to various steps of decomposition of all the three complexes were evaluated.

ChemInform Abstract: 13C NMR Spectral Analysis of Mono and Diphenylarsine Adducts of Glutathione in DMSO.

ChemInform Abstract: 13C NMR Spectral Analysis of Mono and Diphenylarsine Adducts of Glutathione in DMSO.

13C NMR spectral analysis of mono and diphenylarsine adducts of glutathione in DMSO

13C NMR spectral analysis of mono and diphenylarsine adducts of glutathione in DMSO

Analysis of mono‐, di‐, and triglycerides by capillary supercritical fluid chromatography

AbstractThe separation of mixed mono‐, di‐, and triglycerides by capillary supercritical fluid chromatography is described. The separations were performed at low operating temperatures, using a carbon dioxide mobile phase, a conventional flame ionization detector, and two different stationary phases, DB‐5 (95% dimethyl‐(5%)‐diphenylpolysiloxane) and DB‐225 (50% cyanopropyl‐methyl‐(50%)‐methylphenylpolysiloxane). Because the separations were performed at low operating temperatures, no thermal degradation of the glycerides was observed. Even under these mild operating conditions, trinervonin, a triglyceride having a molecular weight over 1100 amu, was readily eluted. When rapid pressure programming of the carbon dioxide mobile phase was employed, trinervonin was eluted in less than two minutes. On DB‐5, the mono‐, di‐, and triglycerides eluted in order of increasing molecular weight. A graph of t′r (on DB‐5) versus molecular weight is linear. When DB‐225 was used as the stationary phase, triglycerides eluted in the order of increasing unsaturation. Thus, the order of elution on DB‐225 was tristearin, triolein, trilinolein, and trilinolenin.

Analyses of Mono- and Dihydroxybenzenes in Tobacco Smoke and Pyrolyzates by Glass Capillary Gas Chromatography

Analyses of Mono- and Dihydroxybenzenes in Tobacco Smoke and Pyrolyzates by Glass Capillary Gas Chromatography

Analysis of mono- and disaccharides by high-performance liquid chromatography of the benzyloxime-perbenzoyl derivatives

A group of biologically important mono- and disaccharides are separated by high-performance liquid chromatography of the benzyloxime-perbenzoyl derivatives on a normal-phase microparticulate column with a hexane—dioxane mixture as the eluting solvent. A single, quantifiable derivative of each sugar is fromed easily. These derivatives are detected by UV adsorption at either 230 or 254 nm, with a sensitivity in the picomle range at the former wavelength. The sugars in the residues from the evaporation of small alquots of bioogic fluids (10–100/gml) are derivatized without prior isolation and are determined quantitatively by the use of appropriate internal standards. The analyses could be performed routinely with a simple, inexpensive instrument.

Isolation and analysis of mono-, di-, and trisialogangliosides

Isolation and analysis of mono-, di-, and trisialogangliosides

Isolation and analysis of mono-, di-, and trisialogangliosides

Isolation and analysis of mono-, di-, and trisialogangliosides

Determination of mono‐, di‐, and triglycerides by molecular distillation and thin‐layer chromatography

AbstractAnalysis of mixtures of mono‐, di‐, and triglycerides by molecular distillation and thin‐layer chromatography is described.Mono‐ and diglycerides undergo appreciable acyl migration through the effect of heat during molecular distillation. Nevertheless this technique may be used for the quantitative analysis of mixtures of mono‐, di‐, and triglycerides, provided there are no substances present which catalyze, disproportionation.Thin‐layer chromatographic (TLC) analysis of mono‐, di‐, and triglycerides is fast and simple and can be carried out on a micro‐scale with a high degree of accuracy and precision. It also is extremely sensitive, permitting the quantitative estimation of as little as 0.1% of a single component in a mixture.