scholarly journals Voltammetric Determination of Anethole on La2O3/CPE and BDDE

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Mateusz Kowalcze ◽  
Jan Wyrwa ◽  
Małgorzata Dziubaniuk ◽  
Małgorzata Jakubowska
Keyword(s):  
Detection Limit ◽  
Essential Oil ◽  
Sample Preparation ◽  
Cyclic Voltammograms ◽  
Structure And Properties ◽  
Ethanol Extracts ◽  
First Time ◽  
Herbal Mixtures ◽  
No Sample Preparation

In this work, DPV determination of anethole was presented using various carbon, two-diameter (1.5 and 3 mm) electrodes, that is, BDD, GC, CP, and CP doped by La2O3 and CeO2 nanoparticles. La2O3/CPE to our best knowledge was proposed first time. Cyclic voltammograms confirmed totally irreversible electrode electrooxidation process, controlled by diffusion, in which two electrons take part. The most satisfactory sensitivity 0.885 ± 0.016 µA/mg L−1 in 0.1 mol L−1 acetate buffer was obtained for La2O3/CPE with the correlation coefficient r of 0.9993, while for BDDE it was 0.135 ± 0.003 µA/mg L−1 with r of 0.9990. The lowest detection limit of 0.004 mg L−1 was reached on La2O3/CPE (3 mm), what may be compared with the most sensitive conjugate methods, but in the proposed approach, no sample preparation and analyte separation was needed. Anethole was successfully determined in specially prepared ethanol extracts of herbal mixtures of various compositions, which imitated real products. The proposed procedure was verified in analysis of commercial products, that is, anise essential oil, which contains a large concentration of anethole, and in alcohol drinks like Metaxa, Ouzo, and Rakija, in which the considered analyte occurs on trace levels. Structure and properties of the considered nanopowders and graphite pastes were investigated by EDX, SEM, and EIS.

Chelyabinsk Meteorite

2021 ◽  
Author(s):  
Olga Popova
Keyword(s):  
Energy Deposition ◽  
Seismic Waves ◽  
The Body ◽  
Structure And Properties ◽  
Ural Mountains ◽  
Asteroid Impact ◽  
Unusual Event ◽  
The Earth ◽  
First Time

The asteroid impact near the Russian city of Chelyabinsk on February 15, 2013, was the largest airburst on Earth since the 1908 Tunguska event, causing a natural disaster in an area with a population exceeding 1 million. On clear morning at 9:20 a.m. local time, an asteroid about 19 m in size entered the Earth atmosphere near southern Ural Mountains (Russia) and, with its bright illumination, attracted the attention of hundreds of thousands of people. Dust trail in the atmosphere after the bolide was tens of kilometers long and was visible for several hours. Thousands of different size meteorites were found in the areas south-southwest of Chelyabinsk. A powerful airburst, which was formed due to meteoroid energy deposition, shattered thousands of windows and doors in Chelyabinsk and wide surroundings, with flying glass injuring many residents. The entrance and destruction of the 500-kt Chelyabinsk asteroid produced a number of observable effects, including light and thermal radiation; acoustic, infrasound, blast, and seismic waves; and release of interplanetary substance. This unexpected and unusual event is the most well-documented bolide airburst, and it attracted worldwide attention. The airburst was observed globally by multiple instruments. Analyses of the observational data allowed determination of the size of the body that caused the superbolide, its velocity, its trajectory, its behavior in the atmosphere, the strength of the blast wave, and other characteristics. The entry of the 19-m-diameter Chelyabinsk asteroid provides a unique opportunity to calibrate the different approaches used to model meteoroid entry and to calculate the damaging effects. The recovered meteorite material was characterized as brecciated LL5 ordinary chondrite, in which three different lithologies can be distinguished (light-colored, dark-colored, and impact-melt). The structure and properties of meteorites demonstrate that before encountering Earth, the Chelyabinsk asteroid had experienced a very complex history involving at least a few impacts with other bodies and thermal metamorphism. The Chelyabinsk airburst of February 15, 2013, was exceptional because of the large kinetic energy of the impacting body and the damaging airburst that was generated. Before the event, decameter-sized objects were considered to be safe. With the Chelyabinsk event, it is possible, for the first time, to link the damage from an impact event to a well-determined impact energy in order to assess the future hazards of asteroids to lives and property.

Direct Determination of Nickel in Catalytic-Cracking Feedstocks by Atomic-Absorption Spectrophotometry

1966 ◽  
Vol 20 (4) ◽  
pp. 212-213 ◽  
Author(s):  
J. D. Kerber
Keyword(s):  
Detection Limit ◽  
Atomic Absorption ◽  
Catalytic Cracking ◽  
Direct Determination ◽  
Atomic Absorption Spectrophotometry ◽  
Rapid Testing ◽  
Absorption Spectrophotometry ◽  
Determination Of Nickel ◽  
No Sample Preparation

Nickel in catalytic-cracking feedstocks is determined by atomic-absorption spectrophotometry with no sample preparation other than dilution in p–xylene. A modification of the method of additions permits rapid testing with a detection limit of 0.05 ppm Ni and a precision of 0.05 ppm.

scholarly journals Photoinduced triplet-state electron transfer of platinum porphyrin: a one-step direct method for sensing iodide with an unprecedented detection limit

2015 ◽  
Vol 3 (13) ◽  
pp. 6733-6738 ◽  
Author(s):  
Dilshad Masih ◽  
Shawkat M. Aly ◽  
Erkki Alarousu ◽  
Omar F. Mohammed
Keyword(s):  
Electron Transfer ◽  
Detection Limit ◽  
Triplet State ◽  
Direct Method ◽  
Economical Method ◽  
State Electron ◽  
One Step ◽  
Platinum Porphyrin ◽  
First Time

Herein, we report for the first time the photoinduced triplet-state electron transfer of Pt(ii)TMPyP as an easy, rapid, environmentally friendly, ultra-sensitive and economical method for the determination of iodide in the aqueous phase.

Determination of Six Common Phthalate Plasticizers in Grain Neutral Spirits and Vodka

1995 ◽  
Vol 78 (3) ◽  
pp. 730-735 ◽  
Author(s):  
Jeffrey N Leebowitz ◽  
Rafael Sarmiento ◽  
Sumer M Dugar ◽  
Michael W Ethridge
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Liquid Chromatography ◽  
Sample Preparation ◽  
Sample Injection ◽  
Sample Enrichment ◽  
Injection Methods ◽  
No Sample Preparation ◽  
Direct Sample

Abstract Two direct sample injection methods using liquid chromatography (LC) and gas chromatography coupled with mass spectrometry (GC/MS) were used to determine phthalate residues in grain neutral spirits and vodka. Six reported phthalates were quantitated at concentrations as low as 20 μg/L (20 ppb) with no sample preparation or sample enrichment.

scholarly journals Determination of Sodium Azide in Beverages by Ion Chromatography

2000 ◽  
Vol 83 (6) ◽  
pp. 1410-1414 ◽  
Author(s):  
Harumi Oshima ◽  
Eiji Ueno ◽  
Isao Saito ◽  
Hiroshi Matsumoto
Keyword(s):  
Detection Limit ◽  
Sample Preparation ◽  
Sodium Hydroxide ◽  
Ion Chromatography ◽  
Sodium Azide ◽  
Convenient Method ◽  
Sodium Hydroxide Solution ◽  
Hydrazoic Acid ◽  
Suppressed Conductivity Detection

Abstract A convenient method for determination of sodium azide in beverages using ion chromatography is described. This method combines the specificity for azide with a simple sample preparation using a bubble and trap apparatus that removes any interferences. Sodium azide in a sample was acidified, and the azide was converted to the volatile hydrazoic acid, which was trapped in 2.5mM sodium hydroxide solution. Determination was performed by isocratic ion chromatography using suppressed conductivity detection. Calibration curves were linear for 0.5 to 20 μg/mL sodium azide and the detection limit was 0.05 μg/mL. Recoveries of sodium azide from spiked samples (10.0 μg/g) were more than 82.6%. The method was then used to analyze various beverages.

The Determination of Quartz in Perlite by X-ray Diffraction

1989 ◽  
Vol 33 ◽  
pp. 493-497 ◽  
Author(s):  
R. D. Hamilton ◽  
N. G. Peletis
Keyword(s):  
Detection Limit ◽  
Sample Preparation ◽  
Accurate Determination ◽  
Analytical Techniques ◽  
Crystalline Silica ◽  
X Ray Diffraction ◽  
X Ray ◽  
Precision And Accuracy ◽  
Improved Technique

AbstractIARC's designation of crystalline silica as a “probable carcinogen” triggered the requirement to label products containing greater than 0.1 % crystalline silica. For perlite and other materials which may contain crystalline silica in levels close to 0.1% an accurate determination is critical from both legal and marketing considerations.Existing analytical techniques for the determination of crystalline silica at levels of less than 1.0% were found to be inadequate to meet the new requirements. An improved technique based on x-ray diffraction has been developed specifically to analyze perlite for crystalline silica, which occurs largely in the form of quartz, at the 0.1%. level. The technique employs long counting times and improved sample preparation and mounting to increase both precision and accuracy, and to lower the detection limit to less than 0.1%.The technique was tested on a large number of samples from a variety of sources and proven to give excellent results for all types of expanded perlites and perlite ores. The procedures developed are applicable to a wide variety of materials in addition to perlite.

Rapid Instrumental Fat Determination

1970 ◽  
Vol 53 (5) ◽  
pp. 1080-1081
Author(s):  
A J Malanoski ◽  
E L Greenfield
Keyword(s):  
Specific Gravity ◽  
Sample Preparation ◽  
Screening Tool ◽  
Automatic Computation ◽  
Automated Method ◽  
Aoac Method ◽  
No Sample Preparation ◽  
Plant Control

Abstract The Digital Fat Controller was evaluated for use in plant control and as a screening tool. The determination of fat by the Digital Fat Controller utilizes specific gravity with automatic computation and a “nixie” tube readout. No sample preparation is required and an analysis can be completed in 30–60 sec. Fiftysix samples were analyzed by both the automated method and the official AOAC method.

Chemiluminescent determination of xanthine oxidase activity in milk

1999 ◽  
Vol 66 (3) ◽  
pp. 441-448 ◽  
Author(s):  
STEFANO GIROTTI ◽  
SANDRO LODI ◽  
ELIDA FERRI ◽  
GRAZIELLA LASI ◽  
FABIANA FINI ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Enzyme Activity ◽  
Detection Limit ◽  
Sample Preparation ◽  
Xanthine Oxidase ◽  
Milk Sample ◽  
Uht Milk ◽  
Milk Samples ◽  
Chemiluminescent Method

A chemiluminescent method for determining xanthine oxidase (XOD) activity was developed and applied to the assay of milk enzyme activity using a photomultiplier luminometer. Various kinds of milk and cream samples were analysed for XOD content. In pasteurized milk, XOD activity depended on the fat content and in UHT milk it disappeared owing to the heat treatment. Milk sample preparation was very simple, requiring only homogenization at 40°C followed by a 1[ratio ]10 dilution with UHT (‘XOD-free’) milk. The assay was carried out at 25°C. The response obtained from XOD standard solutions in milk was linear from 0·1 to 500 enzyme units (U) l−1, but for the actual milk samples values ranged only from 1 to 135 U l−1. The detection limit at 2 SD was 0·1 U l−1 in milk, while in buffer it was 100 times lower. The intra-assay and interassay CV for XOD activity in milk were 6–12%.

Chemiluminescence Detection of Nitrite in Nonfat Dried Milk Powders

1982 ◽  
Vol 65 (3) ◽  
pp. 616-618
Author(s):  
Robert C Doerr ◽  
Robert A Gates ◽  
Walter Fiddler
Keyword(s):  
Statistical Analysis ◽  
Sample Preparation ◽  
Colorimetric Method ◽  
Chemiluminescence Detection ◽  
Milk Samples ◽  
Dry Milk ◽  
Nonfat Dry Milk ◽  
No Sample Preparation

Abstract Determination of nitrite in nonfat dry milk powders by chemiluminescence detection was compared with a colorimetric method specifying Griess reagents. The chemiluminescent technique requires no sample preparation, is free from apparent interferences, and is sensitive to 25 ppb nitrite. Statistical analysis shows no difference at P = 0.05 between the colorimetric and chemiluminescent methods, based on the analysis of 16 commercial nonfat dry milk samples.

scholarly journals Development of a multi-mycotoxin LC-MS/MS method for the determination of biomarkers in pig urine

2021 ◽  
Author(s):  
Agnieszka Tkaczyk ◽  
Piotr Jedziniak
Keyword(s):  
Enzymatic Hydrolysis ◽  
Sample Preparation ◽  
Solid Phase ◽  
Urine Samples ◽  
European Medicines Agency ◽  
Alternariol Monomethyl Ether ◽  
Selective Determination ◽  
Relative Standard ◽  
First Time

AbstractAn LC-MS/MS method has been developed for the sensitive and selective determination of 35 mycotoxins (biomarkers of exposure) in pig urine samples. Sample preparation includes creatinine adjustment (with the developed LC-UV method) with enzymatic hydrolysis of pig urine samples followed by liquid-liquid (LLE) extraction. The LLE protocol, as well as enzymatic hydrolysis for indirect mycotoxin glucuronides determination, was optimized in this study. Additionally, two other sample preparation protocols were compared with the developed LLE method: immunoaffinity columns and solid-phase extraction cartridges (Oasis HLB). The detection and quantification of the biomarkers were performed using triple quadrupole mass spectrometry.The method was validated with regard to the guidelines specified by the EMEA (European Medicines Agency). The extraction recoveries were higher than 60% for 77% of the analytes studied, with the intra- and inter-day relative standard deviation being lower than 20% for most of the compounds at four different concentration levels. The limits of quantification ranged from 0.1 ng/mL for zearalenone and sterigmatocystin to 8 ng/mL for nivalenol. To the best knowledge of the authors, the matrix effect was evaluated for the first time in this study for six different urine samples, and the coefficient of variation was found to be lower than 15% for most analytes studied. Finally, the developed method was applied to analyse 56 pig urine samples. Deoxynivalenol (1–20 ng/mL), zearalenone (0.1–1.5 ng/mL) and ochratoxin A (1.5–15 ng/mL) were the main analytes detected in these samples. Moreover, the co-occurrence of alternariol monomethyl ether and alternariol in pig urine is reported herein for the first time.

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