Kinetic determination of primary and secondary amines using a fluoride-selective electrode and based on their reaction with 1-fluoro-2,4-dinitrobenzene

Athanasiou-Malaki, Eleni; Koupparis, Michael A.; Hadjiioannou, T.P.

doi:10.1021/ac00188a012

Cited by 20 publications

(9 citation statements)

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“…On the other hand, NCS is reduced to NHS (succinimide). 30,31 All experimental parameters affecting the reaction rate of NCS with HZ and PHZ (electrode characteristics, concentration of NCS, pH, etc.) were optimized by "one at a time" studies.…”

Section: Resultsmentioning

confidence: 99%

“…Using the standard analyte solutions, we can construct a calibration graph of (10 ΔE/S − 1) versus concentration (fixed-time method), 30 where ΔE is the potential variation in a selected time interval Δt (usually 90 s) and S is the slope of the chloride electrode response, which is determined periodically by successive additions of micro-amounts of 100 μL of 1.0 × 10 −2 -3.0 M KCl standard solutions in 25.0 mL of water mixed with 2.0 mL of buffer solution. HZ and PHZ standard solutions can be determined simultaneously in the concentration ranges of 0.5 -20.0 and 0.8 -25.0 μg mL −1 , respectively.…”

Section: Methodsmentioning

confidence: 99%

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Application of H-Point Standard Addition Method and Partial Least Squares to the Simultaneous Kinetic-Potentiometric Determination of Hydrazine and Phenylhydrazine

et al. 2008

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Electroanalytical techniques are well known as excellent and cheap procedures for the determination of trace chemical species. Chemometric methods are increasingly used in electroanalytical chemistry for extraction of more information from experimental data as in other areas of analytical chemistry. [1][2][3][4][5][6][7][8][9][10] In the field of potentiometry, several methods have been reported based on flow injection system and titration using partial least squares (PLS) regression and artificial neural networks (ANN) as modeling methods. 11-16 Based on our knowledge, there is not any report about using chemometrics methods for simultaneous determination of two or more species based on kinetic-potentiometric data.Hydrazine (HZ) and phenylhydrazine (PHZ) as its derivative have been used in industry, agriculture and other fields. 17 Several methods have been reported for the determination of HZ and its derivatives individually.18-24 H-point standard addition method (HPSAM) was reported for simultaneous determination of binaries of HZ and semicarbzide, 25 HZ and PHZ, 26 HZ and acetylhydrazine, 27 HZ and isoniazid. 28 Recently, we reported a kinetic-spectrophotometric determination of ternary mixture of HZ and its derivatives using PCR and PLS methods. 29 To the best of our knowledge, no one has reported any chemometric methods for the simultaneous determination of HZ and its derivatives in a mixture, based on the kinetic-potentiometric method in which ion-selective electrodes are used.This work reports the first application of HPSAM and PLS to the simultaneous kinetic-potentiometric determination of binary mixture of HZ and PHZ. The methods are based on the differences observed in the rate of production of chloride ion in the reactions of NCS with HZ and PHZ. Experimental Apparatus and softwareA solid-state chloride-selective electrode (Metrohm Model 6.0502.120) was used in conjunction with a double junction Ag/AgCl reference electrode (Metrohm Model 6.0726.100), whose outer compartment was filled with a 10% (w/v) KNO3 solution. The Metrohm Model 780 potentiometer, attached to a Pentium (IV) computer, was used for recording the kinetic potentiometric data. All measurements were carried out in a thermostated (25 ± 0.2˚C), double-walled reaction cell with continuous magnetic stirring. The electrode was stored in 1 × 10 −3 mol dm −3 potassium chloride solution when not in use. For pH measurements, a Metrohm Model 780 pH meter with a combination glass electrode was used. PLS analysis was performed using a PLS toolbox in the MATLAB 7.0 program. Simultaneous determination of hydrazine (HZ) and phenylhydrazine (PHZ) by H-point standard addition method (HPSAM) and partial least squares (PLS) regression was carried out based on kinetic data from novel potentiometry methods. The rate of chloride ion production in the reaction of HZ and PHZ with N-chlorosuccinimide (NCS) was monitored by a chloride ion-selective electrode. The experimental data show the good ability of ion-selective electrodes (ISEs) as detectors not only f...

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Application of H-Point Standard Addition Method and Partial Least Squares to the Simultaneous Kinetic-Potentiometric Determination of Hydrazine and Phenylhydrazine

et al. 2008

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“…[1][2][3][4][5][6][7] For this purpose, 1-fluoro-2,4-dinitrobenzene [1][2][3][4] and Girard's reagent 3,[5][6][7] are widely used. The former reagent can release fluoride by the reaction with amino acids, amines, hydrazines or phenols, so that a fluoride-selective electrode can be used for the determination of these compounds.…”

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confidence: 99%

“…(1) Thus, the concentration of NAD(P)H can be determined through the detection of NO 2 -. This approach is very useful because many enzyme reactions can be coupled with the formation of the coenzymes.…”

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Potentiometric Determination of NAD(P)H Coenzymes Using a Nitrite-Selective Membrane Electrode and a Nitrate Reductase Enzyme and the Application to Glucose Assay in Human Serum

1999

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NAD(P)H coenzyme concentrations were determined with the combination of a nitrite-selective membrane electrode and a nitrate reductase enzyme. The method was based on the detection of nitrite formed by the enzymatic reaction of NAD(P)H with nitrate catalyzed by nitrate reductase. The lower detection limits for both these coenzymes were around 100 µM. This system was applied to detect glucose by combining an additional glucose dehydrogenase enzyme. Serum glucose levels could be determined through the detection of nitrite.

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Instrumentation for Kinetics

Cordos

2000

Encyclopedia of Analytical Chemistry

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In kinetic methods or reaction‐rate methods of analysis, the rate of a given reaction is measured and related to the concentration of the sought‐for species. The instrumentation in kinetics is primarily designed to monitor the evolution of the analytical signal with time. Unlike in the traditional equilibrium‐based approaches, where the signal is measured after the reaction has reached completion, in kinetic methods the signal is usually measured in the first few percent of the total reaction time. Therefore, the advantages and limitations of kinetic methods should be considered in their relations with equilibrium methods. Kinetic methods are faster than equilibrium‐based methods since the user does not have to wait for a reaction to go to completion. They are relative methods that depend on changes in concentration and not on its absolute value and they could be more selective than equilibrium methods since the difference between reaction constants could be used to discriminate against an interfering species. The limitations of kinetic methods are a lower precision and a strong dependence on experimental conditions. The main factors that cause these limitations are the measured signal, which is small in comparison with that from an equilibrium reaction, and the dependence of rate constants on temperature, pH, ionic strength, etc. Therefore, the measurement systems used in kinetic methods should be sensitive and the experimental conditions should be kept strictly constant. The best results in kinetic methods are obtained with instrumental systems having a high degree of automation. The main operations that should be carried out by the instrumentation in kinetic determinations are the mixing of the reactants, measurement of the detector signal in time and processing of data to obtain the reaction rate and concentration. The mixing of the reactants should be done in a time shorter than the reaction half‐life and it is critical for fast reactions where required mixing times are of the order of milliseconds. In these cases the mixing is accomplished by mechanical systems that rapidly drive the reactants through a mixing chamber into an observation chamber. For slower reaction the best mixing procedures are based on automated flow analyzers that have different manifolds configurations adapted both to sample processing and to reactant mixing. After mixing, the reaction could be monitored in time either by stopping the flow and recording the signal or by passing the reacting plug several times through the detector and reading the signal after each pass. The measurement of the detector signal, after the reagents are mixed, could be done with a large variety of detectors, but the most commonly used detection systems are photometric and electrochemical. Photometric detection provides a short response time, specificity and the possibility of collecting full spectra very rapidly if photodetector arrays are used. Electrochemical detectors are simple and relatively inexpensive. The concentration of the analyte is determined from the slope of the detector signal. In many routine procedures the slope is determined by measuring the signal at one or two fixed points in time or by determining the time required by the signal to reach a predetermined level. These procedures have the advantage that they are rapid and need no supplementary instrumentation for data processing. Another approach in kinetic data processing, based on computer software, computes a curve that fits the experimental data. The slope or concentration is then extracted from the mathematical expression of the fitting curve.

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Kinetic determination of primary and secondary amines using a fluoride-selective electrode and based on their reaction with 1-fluoro-2,4-dinitrobenzene

Cited by 20 publications

References 61 publications

Application of H-Point Standard Addition Method and Partial Least Squares to the Simultaneous Kinetic-Potentiometric Determination of Hydrazine and Phenylhydrazine

Application of H-Point Standard Addition Method and Partial Least Squares to the Simultaneous Kinetic-Potentiometric Determination of Hydrazine and Phenylhydrazine

Potentiometric Determination of NAD(P)H Coenzymes Using a Nitrite-Selective Membrane Electrode and a Nitrate Reductase Enzyme and the Application to Glucose Assay in Human Serum

Instrumentation for Kinetics

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