Continuous on-line true titrations by feedback based flow ratiometry: application to potentiometric acid–base titrations

Dasgupta, Purnendu Κ.; Tanaka, Hideji; Jo, Kyoo Dong

doi:10.1016/s0003-2670(01)00864-9

Cited by 20 publications

(14 citation statements)

References 12 publications

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“…The scan rate of Vc for feedback-based control was set at 50 mV s -1 by refereeing to the results of a previous study. 13 Temporal titration profile and titration curve Figure 3A shows a typical temporal profile of Vc and Vd for the titration of 0.1 mol dm -3 HCl with the same concentration of NaOH containing ca. 30 mmol dm -3 Bromothymol Blue as an acid-base indicator (acid form, yellow; base form, blue).…”

Section: Basic Conditions For the Measurementmentioning

confidence: 99%

“…11 Tanaka et al 12,13 proposed a feedback-based flow ratiometry, a new concept for continuous titration. In their approach, the titrant flow rate is linearly varied while the total (titrant + titrand) flow rate (FT) is held constant.…”

mentioning

confidence: 99%

“…Thus, the scan range is limited to the range around EP. A high throughput was attained for photometric 12 and potentiometric 13 titrtions (6 and 5 titrations per minute, respectively). Jo and Dasgupta 14 applied this method to cheletometric titrations.…”

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confidence: 99%

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High-Throughput Photometric Titrimetry Based on a Feedback-based and Subsequent Fixed Triangular Wave-controlled Flow Ratiometry

Tanaka

Baba

2005

ANAL. SCI.

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Titrimetry is a classical analytical method that is still widely in use. It is adopted, for example, as a method for the quantitative analysis of nearly 60% of drugs listed in Part 1 of the Japanese Parmacopoeia. 1 According to a book by Szabadváry, 2 the origin of titrimetry can be traced back to 1729 when Geoffroy analyzed vinegar samples with K2CO3. However, conventional manual titration using glassware, such as a burette, is tedious and time-consuming. Various flow titration techniques have therefore been developed, as recently reviewed by Tanaka and Nakano. 3These include flow injection titration, 4 sequential injection titration, 5 triangle programmed coulometric titration, 6-8 flow ratiometric titration 9,10 and monosegmented flow titration. 11 Tanaka et al. 12,13 proposed a feedback-based flow ratiometry, a new concept for continuous titration. In their approach, the titrant flow rate is linearly varied while the total (titrant + titrand) flow rate (FT) is held constant. The scan direction of the titrant flow rate is reversed from upward to downward, and vice versa, whenever the equivalence point EP is detected. Thus, the scan range is limited to the range around EP. A high throughput was attained for photometric 12 and potentiometric 13 titrtions (6 and 5 titrations per minute, respectively). Jo and Dasgupta 14 applied this method to cheletometric titrations.Very recently, we introduced a new strategy to feedback-based flow ratiometry. 15 After feedback-based operation, fixed triangular waves were used to control the titrant flow rate in order to further limit the scan to the range of interest. The developed method realized potentiometric titrations having an extremely high throughput rate at reasonable precision (maximally 17.6 titrations per minute at RSD = 0.35%). In the present study, we extended the principle of the method to photometric titrimetry, because the photo-sensor is one of the most popular detectors in flow analyses, and is expected to have a quicker response than an electrode. ExperimentalFlow system Figure 1 shows the flow system of the present study. The principle of flow ratiometry for high-throughput titration, which we recently proposed for potentiometric titration, was extended to photometric titration. The flow rate (FB) of a base solution containing an acid-base indicator was linearly varied in response to a control voltage (Vc) generated from a computer. With the total (acid + base) flow rate (FT) being kept constant, the base solution was merged with an acid solution, which was aspirated to the confluence point at a flow rate of FT -FB. Downstream, the relative transmittance of the mixed solution was measured at the maximum absorption wavelength of the base form of the indicator. Initially, a feedback-based control was applied, where the scan direction of Vc was reversed from upward to downward, and vice versa, whenever the transition of the indicator at the equivalence point (EP) was sensed. Next, the scan range of Vc was further limited to the range just around EP by using f...

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Section: Basic Conditions For the Measurementmentioning

confidence: 99%

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confidence: 99%

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High-Throughput Photometric Titrimetry Based on a Feedback-based and Subsequent Fixed Triangular Wave-controlled Flow Ratiometry

Tanaka

Baba

2005

ANAL. SCI.

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“…Titrimetry reckons to the oldest analytical methods, still widely used because of high precision, accuracy, convenience, and affordability [1]. Nowadays, according to Comité Consultatif pour la Quantité de la Matière (CCQM) opinion [2], it is considered as one of the primary methods of analysis i.e., it fulfills the demands of the highest metrological qualities.…”

Section: Introductory Remarksmentioning

confidence: 99%

Principles of Titrimetric Analyses According to Generalized Approach to Electrolytic Systems (GATES)

Michałowska-Kaczmarczyk¹,

Spórna‐Kucab²,

Michałowski³

2017

Advances in Titration Techniques

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The generalized equivalent mass (GEM) concept, based on firm algebraic foundations of the generalized approach to electrolytic systems (GATES), is considered and put against the equivalent "weight" concept, based on a "fragile" stoichiometric reaction notation still advocated by IUPAC. The GEM is formulated a priori, with no relevance to a stoichiometry. GEM is formulated in a unified manner, and referred to systems of any degree of complexity with special emphasis put on redox systems, where generalized electron balance (GEB) is involved. GEM is formulated on the basis of all attainable (and preselected) physicochemical knowledge on the system in question, and resolved with use of iterative computer programs. It is possible to calculate coordinates of the end points taken from the vicinity of equivalence point. This way, one can choose (among others) a proper indicator and the most appropriate (from analytical viewpoint) color change of the indicator. Some interpolative and extrapolative methods of equivalence volume V eq determination are recalled and discussed. The GATES realized for GEM purposes provides the basis for optimization of analytical procedures a priori. The GATES procedure realized for GEM purposes enables to foresee and optimize new analytical methods, or modify, improve, and optimize old analytical methods.

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“…These methods have been extensively applied to environmental and clinical analyses and to process monitoring because of their excellent advantages in precision, sample throughput, costs, and compatibility with computers compared to conventional batch methods. Recently, one of the authors (H. T.) 4,5 proposed feedback-based flow ratiometry, a new concept of flow analysis, for continuous on-line true titration. In this method, the flow rate ratio of titrand and titrant was varied in a triangular wave fashion.…”

Section: Introductionmentioning

confidence: 99%

Analytical Parameters for Amplitude-Modulated Multiplexed Flow Analysis

2010

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Continuous on-line true titrations by feedback based flow ratiometry: application to potentiometric acid–base titrations

Cited by 20 publications

References 12 publications

High-Throughput Photometric Titrimetry Based on a Feedback-based and Subsequent Fixed Triangular Wave-controlled Flow Ratiometry

High-Throughput Photometric Titrimetry Based on a Feedback-based and Subsequent Fixed Triangular Wave-controlled Flow Ratiometry

Principles of Titrimetric Analyses According to Generalized Approach to Electrolytic Systems (GATES)

Analytical Parameters for Amplitude-Modulated Multiplexed Flow Analysis

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