scholarly journals Novel Approach to Automated Flow Titration for the Determination of Fe(III)

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1533 ◽  
Author(s):  
Joanna Kozak ◽  
Justyna Paluch ◽  
Marek Kozak ◽  
Marta Duracz ◽  
Marcin Wieczorek ◽  
...  
Keyword(s):  
Reference Method ◽  
Good Precision ◽  
Concentration Gradients ◽  
Spectrophotometric Detection ◽  
Simultaneous Control ◽  
Novel Approach ◽  
Wide Range ◽  
Artesian Water ◽  
Flow Titration

A novel approach to automated flow titration with spectrophotometric detection for the determination of Fe(III) is presented. The approach is based on the possibility of strict and simultaneous control of the flow rates of sample and titrant streams over time. It consists of creating different but precisely defined concentration gradients of titrant and analyte in each successively formed monosegments, and is based on using the calculated titrant dilution factor. The procedure was verified by complexometric titration of Fe(III) in the form of a complex with sulfosalicylic acid, using EDTA as a titrant. Fe(III) and Fe(II) (after oxidation to Fe(III) with the use of H2O2) were determined with good precision (CV lower than 1.7%, n = 6) and accuracy ( | RE | lower than 3.3%). The approach was applied to determine Fe(III) and Fe(II) in artesian water samples. Results of determinations were consistent with values obtained using the ICP–OES reference method. Using the procedure, it was possible to perform titration in 6 min for a wide range of analyte concentrations, using 2.4 mL of both sample and titrant.

Combined enzymic-Jaffé method for determination of creatinine in serum.

1981 ◽  
Vol 27 (1) ◽  
pp. 18-21 ◽  
Author(s):  
P Masson ◽  
P Ohlsson ◽  
I Björkhem
Keyword(s):  
Reference Method ◽  
Enzyme Reaction ◽  
Creatine Phosphate ◽  
Mass Fragmentography ◽  
Good Precision ◽  
Serum Samples ◽  
Modified Method ◽  
Combined Use ◽  
High Concentrations

Abstract Concentrations of creatinine, as determined in serum by a method involving the combined use of creatinine amidohydrolase (EC 3.5.2.10) and alkaline sodium picrate were found to be factitiously low, owing to a reversal of the enzyme reaction. This effect could be eliminated by converting creatine, the product of the enzymic reaction, to creatine phosphate. The combined enzymic-Jaffé method was therefore modified to include creatine amidohydrolase, creatine kinase, ATP, and Mg2+ in the reaction mixture. The modified method has good precision. We saw no significant interferences by relatively high concentrations of acetone, acetylacetone, ADP, creatine, creatine phosphate, glucose, glycocyamine, or pyruvate. Likewise, no interferences were evident with icteric, lipemic, or hemolytic serum samples. There was an excellent agreement between creatinine values obtained with our method and by a reference method based on isotope dilution-mass fragmentography. Our method is considerably simpler than the fully enzymic method for determination of creatinine and might be a method of choice if a high accuracy is desired.

scholarly journals DETERMINATION OF ACETATE IN FOODS BY ION CHROMATOGRAPHY-FLOW INJECTION

1995 ◽  
Vol 3 (3) ◽  
pp. 9-22
Author(s):  
E. Esteve-Juan ◽  
R. Puchades ◽  
A. Maquieira
Keyword(s):  
Standard Deviation ◽  
Detection Limit ◽  
Ion Chromatography ◽  
Chromatographic Analysis ◽  
Reference Method ◽  
Spectrophotometric Detection ◽  
Flow Rates ◽  
Injection Volume ◽  
Relative Standard

A method for acetate determination using IC separation and FI post-column spectrophotometric detection based on the La(OH)3-I2 reaction has been developed. The chromatographic conditions (eluants, flow-rates, sensitivity, and so on) and FI variables (length of coils, injection volume, pH, ... ) were optimized. Linearity was observed over the concentration range 0 to 1 gl-1 with HAc as standard (r = 0.9916) and a detection limit of 0.1 g AcH/l. The IC-FI method afforded a low relative standard deviation (3.6%) and was free from interferences. The IC-FI procedure was applied to the determination of acetate in mustard sauce and the results obtained agree with those provided by the reference method. Additionally, the developed method permits the simultaneous chromatographic analysis of other anions such as chloride, nitrate, phosphate, sulphate, and so on.

scholarly journals A Novel Approach for Measurement of Composition and Temperature of N-Decane/Butanol Blends Using Two-Color Laser-Induced Fluorescence of Nile Red

Sensors ◽  
2020 ◽  
Vol 20 (19) ◽  
pp. 5721
Author(s):  
Matthias Koegl ◽  
Mohammad Pahlevani ◽  
Lars Zigan
Keyword(s):  
Nile Red ◽  
Spectral Shift ◽  
Laser Induced Fluorescence ◽  
Temperature Changes ◽  
Novel Approach ◽  
Detection Approach ◽  
Wide Range ◽  
Fuel Mixtures ◽  
Butanol Concentration

In this work, the possibility of using a two-color LIF (laser-induced fluorescence) approach for fuel composition and temperature measurements using nile red dissolved in n-decane/butanol blends is investigated. The studies were conducted in a specially designed micro cell enabling the detection of the spectral LIF intensities over a wide range of temperatures (283–423 K) and butanol concentrations (0–100 vol.%) in mixtures with n-decane. Furthermore, absorption spectra were analyzed for these fuel mixtures. At constant temperature, the absorption and LIF signals exhibit a large spectral shift toward higher wavelengths with increasing butanol concentration. Based on this fact, a two-color detection approach is proposed that enables the determination of the butanol concentration. This is reasonable when temperature changes and evaporation effects accompanied with dye enrichment can be neglected. For n-decane, no spectral shift and broadening of the spectrum are observed for various temperatures. However, for butanol admixture, two-color thermometry is possible as long as the dye and butanol concentrations are kept constant. For example, the LIF spectrum shows a distinct broadening for B20 (i.e., 80 vol.% n-decane, 20 vol.% butanol) and a shift of the peak toward lower wavelengths of about 40 nm for temperature variations of 140 K.

scholarly journals MICELLAR ENHANCED SYNCHRONOUS FLUORESCENCE FOR THE ASSAY OF SUMATRIPTAN SUCCINATE IN PHARMACEUTICAL TABLETS

2019 ◽  
pp. 218-223
Author(s):  
SAFWAN M. FRAIHAT
Keyword(s):  
Limit Of Detection ◽  
Fluorescence Emission ◽  
Reference Method ◽  
Synchronous Fluorescence ◽  
Pharmaceutical Tablets ◽  
Sumatriptan Succinate ◽  
Accuracy And Precision ◽  
Relative Standard ◽  
Wide Range

Objective: To develop a sensitive, fast and selective method for the determination of sumatriptan succinate (SUM) in pharmaceutical samples. Methods: The method is based on measuring the synchronous fluorescence of SUM using ∆λ of (120 nm) and at a wavelength of excitation and emission of 230 and 325 nm respectively, using Agilent Technology, Cary eclipse, G9800AA model Luminescence spectrometer. Effect of variables on fluorescence emission intensities was studied such as solvent, surfactant, and pH. The proposed method was validated in term of linearity, limit of detection as per the international conference on harmonization guidelines ICH Q2 (R1). Results: The linearity of the method was obtained with a wide range of (50-150) ng/ml with a high value of correlation coefficient value of (0.992). Limits of detection (LOD) and limits of quantitation (LOQ) were found to be 16.3 and 49.5 ng/ml respectively, the mean recovery was found to be 99.1% with low relative standard deviation (% RSD). The method was also compared statistically with the reference method using t-test and f-test, the results show no difference either in pure or pharmaceutical tablets. Conclusion: The obtained results revealed that the developed method can be applied successfully for the determination of SUM in drug formulations samples with good accuracy and precision.

scholarly journals Rutin in buckwheat grain meal determined by UV photoacoustic spectroscopy and HPLC

2017 ◽  
Vol 16 (1) ◽  
pp. 61-67 ◽  
Author(s):  
Ottó Dóka ◽  
Andrea Brunori ◽  
Rezső Schmidt ◽  
Dane Bicanic ◽  
György Végvári
Keyword(s):  
Photoacoustic Spectroscopy ◽  
Reference Method ◽  
Dry Weight ◽  
Tartary Buckwheat ◽  
Fagopyrum Tataricum ◽  
Quick Method ◽  
Novel Approach ◽  
Quick Determination ◽  
Hplc Data

AbstractA relatively novel approach for easy and quick determination of rutin in buckwheat grain is suggested. The rutin content of the grain in seven common buckwheat (Fagopyrum esculentum) and six Tartary buckwheat (Fagopyrum tataricum) varieties was investigated by means of UV photoacoustic spectroscopy and HPLC as reference method. The lowest content was found in ‘Botan’ and ‘Bamby’ varieties, while the highest values were obtained in the variety ‘Emka’. Rutin content in grain of all Tartary buckwheat varieties was two orders of magnitude higher than in the other varieties. Rutin content in F. esculentum ranges between 9 and 36 mg/100 g dry weight as compared to 921 to 2 132 mg/100 g dry weight in F. tataricum. The UV photoacoustic spectroscopy data show rather good correlations of R2=0.977 and R2=0.980 with values obtained by HPLC data for all measured samples. Therefore, UV photoacoustic spectroscopy can be a cheap and quick method for determining rutin content in buckwheat grain.

scholarly journals A novel approach to non-segmented flow analysis: Part 3. Nitrate, nitrite and ammonium in waters

1988 ◽  
Vol 10 (4) ◽  
pp. 192-197 ◽  
Author(s):  
D. J. Malcolme-Lawes ◽  
C. Pasquini
Keyword(s):  
Flow Injection ◽  
Flow Injection Analysis ◽  
Continuous Flow ◽  
High Performance ◽  
Flow Analysis ◽  
Ammonium Ion ◽  
Sequential Determination ◽  
Novel Approach ◽  
Wide Range

A high-performance continuous-flow analyser is used for the analysis of nitrate, nitrite and ammonium ion in potable waters. The results demonstrate that (1) the analyser allows the sequential determination of a number of analytes without requiring modification to the manifold; (2) the use of programmed slicing of the reaction mixture allows a wide range of analyte concentrations to be handled; and (3) that the sensitivity achieved compares favourably with the best available from conventional flow-injection analysis. The limits of detection were found to be 5 ppb for NH4+, 30 ppb for NO3-, and 4 ppb for NO2-.

Determination of heat losses for sections of main heat pipelines using the reference method

2017 ◽  
Vol 20 (1) ◽  
pp. 22-27
Author(s):  
O. Tsakanyan ◽  
◽  
V. Goloshchapov ◽  
S. Koshel ◽  
N. Ganzha ◽  
...  
Keyword(s):  
Reference Method ◽  
Heat Losses

The Use of TMAH to Etch Silicon and Expose Metal Bridging Failures

2000 ◽  
Author(s):  
Mark Morris ◽  
James Mohr ◽  
Esteban Ortiz ◽  
Steven Englebretson
Keyword(s):  
Failure Mechanism ◽  
Schottky Diodes ◽  
Tetramethylammonium Hydroxide ◽  
Novel Approach ◽  
Failure Location ◽  
Metal Etching ◽  
Plastic Mold

Abstract Determination of metal bridging failures on plastic encapsulated devices is difficult due to the metal etching effects that occur while removing many of the plastic mold compounds. Typically, the acids used to remove the encapsulation are corrosive to the metals that are found within the device. Thus, decapsulation can result in removal of the failure mechanism. Mechanical techniques are often not successful due to damage that results in destruction of the die and failure mechanism. This paper discusses a novel approach to these types of failures using a silicon etch and a backside evaluation. The desirable characteristics of the technique would be to remove the silicon and leave typical device metals unaffected. It would also be preferable that the device passivation and oxides not be etched so that the failure location is not disturbed. The use of Tetramethylammonium Hydroxide (TMAH), was found to fit these prerequisites. The technique was tested on clip attached Schottky diodes that exhibited resistive shorting. The use of the TMAH technique was successful at exposing thin solder bridges that extruded over the edge of the die resulting in failure.

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