scholarly journals Quick Multicomponent Analysis Based on Matrix Isopotential Synchronous Fluorimetry

2012 ◽  
Vol 2012 ◽  
pp. 1-6
Author(s):  
Géza Makkai ◽  
János Erostyák

Fast and precise methods are important in chemical and physical analysis, but determination of concentration of selected components in mixtures may have special difficulties. Excitation-emission matrices (EEM) are widely used in characterizing fluorescence emission. Based on these primary data, we present an improvement of matrix isopotential synchronous fluorimetry (MISF) and a method which ensures a very fast multicomponent analysis. MISF is generally combined with derivative technique (DMISF) to be able to eliminate the contribution of the background emission. Unfortunately, it is too sensitive to noises and fluctuations; thus the concentration region where it can be used, was limited until now. Our first aim was to reduce the influence of measurement errors and to increase the sensitivity of known MISF method by more than one order of magnitude. As a further result, using improved MISF, we got a method which ensures very fast determination of the wanted compound's concentration both in presence of one- or even two-component background of unknown concentration.

The Analyst ◽  
2018 ◽  
Vol 143 (16) ◽  
pp. 3900-3906 ◽  
Author(s):  
Yang Wang ◽  
Hongkun Xiang ◽  
Rongrong Zhao ◽  
Chusen Huang

We developed a new technique combining a renewable test strip and solid-state ratiometric fluorescence readout for the fast capture and quantification of N2H4 gas.


2019 ◽  
Vol 7 (2A) ◽  
Author(s):  
Camilo Fuentes Serrano ◽  
Juan Reinaldo Estevez Alvares ◽  
Alfredo Montero Alvarez ◽  
Ivan Pupo Gonzales ◽  
Zahily Herrero Fernandez ◽  
...  

A method for determination of Cr, Fe, Co, Ni, Cu, Zn, Hg and Pb in waters by Energy Dispersive X Ray Fluorescence (EDXRF) was implemented, using a radioisotopic source of 238Pu. For previous concentration was employed a procedure including a coprecipitation step with ammonium pyrrolidinedithiocarbamate (APDC) as quelant agent, the separation of the phases by filtration, the measurement of filter by EDXRF and quantification by a thin layer absolute method. Sensitivity curves for K and L lines were obtained respectively. The sensitivity for most elements was greater by an order of magnitude in the case of measurement with a source of 238Pu instead of 109Cd, which means a considerable decrease in measurement times. The influence of the concentration in the precipitation efficiency was evaluated for each element. In all cases the recoveries are close to 100%, for this reason it can be affirmed that the method of determination of the studied elements is quantitative. Metrological parameters of the method such as trueness, precision, detection limit and uncertainty were calculated. A procedure to calculate the uncertainty of the method was elaborated; the most significant source of uncertainty for the thin layer EDXRF method is associated with the determination of instrumental sensitivities. The error associated with the determination, expressed as expanded uncertainty (in %), varied from 15.4% for low element concentrations (2.5-5 μg/L) to 5.4% for the higher concentration range (20-25 μg/L).


2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Astri Furqani ◽  
Hafidhah .

In this era, a lot of activities that can not be separated from the practice of cheating or fraud , no exception In the government . Inspektorat Sumenep is the leading institution of internal Local Government in preventing and detecting fraud in the Local Government appropiate Perbup Sumenep No. 29 of 2008 . Dinas Pendidikan Sumenep need attention on the issue . This is due to Dinas Pendidikan Sumenep an agency with the largest number of assets and managing large budgets . These conditions led to the formulation of the problem is How Inspektorat Sumenep role in preventing and detecting fraud in Dinas Pendidikan Sumenep. This study used a qualitative approach in which the focus of this study is Inspektorat role in preventing and detecting fraud at Dinas Pendidikan Sumenep . Primary data obtained by direct interviews with the parties directly related to the determination of the source of research data in a qualitative study using nonprobability sampling . The sampling technique used was purposive sampling . The conclusion of this study, role of the Inspektorat Sumenep in the prevention of fraud in Dinas Pendidikan Sumenep still not maximal . This is due to Inspektorat Sumenep not supervise from the planning / budgeting and not optimal in overseeing and assisting the implementation of the SPIP as an instrument of fraud prevention in Dinas Pendidikan Sumenep . The role of Inspektorat Sumenep in the detection of fraud in Dinas Pendidikan Sumenep done by conducting an audit of financial and asset management in each financial year.Keywords: fraud, government, inspektorat.


2018 ◽  
Author(s):  
Suwandi S. Sangadji

The purpose of this researchment is to ascertain how wide the farming of species Saccharun Edule Hasskarl (terubuk) in sub district Tosa, district of East Tidore of Tidore Island through the indicator of the value revenue, production and selling prices so that the farmers will achieve The Break Event Point (BEP). The research method was used a quantitative method with the number of samples of 30 people. The determination of the sample method is using the census method or involving all members of the population into a sample of researchment. The secondary data collection was done by using library literature in the form of document review and relevant references to research object while primary data collection was done by using questionnaire. The data is using equation R /C Ratio, BEP Revenue, BEP Price, and BEP Production. Therefore from the results of the researchment it can be explained that the two of the thirty farmers come through the break event point, while the other twenty-eight farmers declared having a business that worth to be develop or experiencing profit, because the R/C ratio is above 1.0 with average profit reach Rp. 989.000, - per production / farmer.


1982 ◽  
Vol 47 (7) ◽  
pp. 1973-1978 ◽  
Author(s):  
Jiří Karhan ◽  
Zbyněk Ksandr ◽  
Jiřina Vlková ◽  
Věra Špatná

The determination of alcohols by 19F NMR spectroscopy making use of their reaction with hexafluoroacetone giving rise to hemiacetals was studied on butanols. The calibration curve method and the internal standard method were used and the results were mutually compared. The effects of some experimental conditions, viz. the sample preparation procedure, concentration, spectrometer setting, and electronic integration, were investigated; the conditions, particularly the concentrations, proved to have a statistically significant effect on the results of determination. For the internal standard method, the standard deviation was 0.061 in the concentration region 0.032-0.74 mol l-1. The method was applied to a determination of alcohols in the distillation residue from an oxo synthesis.


1991 ◽  
Vol 56 (7) ◽  
pp. 1434-1445 ◽  
Author(s):  
Jiří Barek ◽  
Ivana Švagrová ◽  
Jiří Zima

Polarographic reduction of the genotoxic N,N’-dinitrosopiperazine was studied and its mechanism was suggested. Optimum conditions were established for the determination of this substance by tast polarography over the concentration region of 1 . 10-3 to 1 . 10-6 mol l-1 and by differential pulse polarography on the conventional dropping mercury electrode or by fast scan differential pulse voltammetry and linear sweep voltammetry on a hanging mercury drop electrode over the concentration region of 1 . 10-3 to 1 . 10-7 mol l-1. Attempts at increasing further the sensitivity via adsorptive accumulation of the analyte on the surface of the hanging mercury drop failed. The methods are applicable to the testing of the chemical efficiency of destruction of the title chemical carcinogen based on its oxidation with potassium permanganate in acid solution.


Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1238
Author(s):  
Eduardo Laga ◽  
David Dalmau ◽  
Sofía Arregui ◽  
Olga Crespo ◽  
Ana I. Jimenez ◽  
...  

The goal of the work reported here was to amplify the fluorescent properties of 4-aryliden-5(4H)-oxazolones by suppression of the hula-twist non-radiative deactivation pathway. This aim was achieved by simultaneous bonding of a Pd center to the N atom of the heterocycle and the ortho carbon of the arylidene ring. Two different 4-((Z)-arylidene)-2-((E)-styryl)-5(4H)-oxazolones, the structures of which are closely related to the chromophore of the Kaede protein and substituted at the 2- and 4-positions of the arylidene ring (1a OMe; 1b F), were used as starting materials. Oxazolones 1a and 1b were reacted with Pd(OAc)2 to give the corresponding dinuclear orthometalated palladium derivates 2a and 2b by regioselective C–H activation of the ortho-position of the arylidene ring. Reaction of 2a (2b) with LiCl promoted the metathesis of the bridging carboxylate by chloride ligands to afford dinuclear 3a (3b). Mononuclear complexes containing the orthopalladated oxazolone and a variety of ancillary ligands (acetylacetonate (4a, 4b), hydroxyquinolinate (5a), aminoquinoline (6a), bipyridine (7a), phenanthroline (8a)) were prepared from 3a or 3b through metathesis of anionic ligands or substitution of neutral weakly bonded ligands. All species were fully characterized and the X-ray determination of the molecular structure of 7a was carried out. This structure has strongly distorted ligands due to intramolecular interactions. Fluorescence measurements showed an increase in the quantum yield (QY) by up to one order of magnitude on comparing the free oxazolone (QY < 1%) with the palladated oxazolone (QY = 12% for 6a). This fact shows that the coordination of the oxazolone to the palladium efficiently suppresses the hula-twist deactivation pathway.


2004 ◽  
Vol 18 (4) ◽  
pp. 665-668 ◽  
Author(s):  
M.M.H Huisman ◽  
A Oosterveld ◽  
H.A Schols

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