A potential high-throughput method for the determination of lipase activity by potentiometric flow injection titrations

Vahl, Katja; Kahlert, Heike; Böttcher, Dominique; Wardenga, Rainer; Komorsky‐Lovrić, Šebojka; Bornscheuer, Uwe T.; Scholz, Fritz

doi:10.1016/j.aca.2008.01.014

Cited by 8 publications

(9 citation statements)

References 30 publications

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“…23,24] and quinhydrone in a ratio 10 : 1 in a ball mill. To 1.1 g of that mixture 1 g silicone (Aquarium Silikon, Masterfix, Warenimport & Handels GmbH, Wien, Austria) was added, and the resulting paste was carefully mixed before it was pressed to obtain a planar layer of 1 mm thickness.…”

Section: The Fia Titration Systemmentioning

confidence: 99%

“…A single line FIA configuration comparable to that described in [23,24] was used. The major differences were that (i) we used silicone as a binder for the pH sensitive layer instead of polymethylmethacrylate (PMMA), and (ii) the contact to the reference electrode was established via a gel filled tube acting as a salt bridge which was placed as close as possible to the sensitive layer to avoid marked potential drops due to a possible high resistance of solutions with a low ionic strength.…”

Section: The Fia Titration Systemmentioning

confidence: 99%

“…Recently, we have introduced solid composite electrodes based on quinhydrone as detectors in FIA acid-base titrations [23][24][25]. These detectors proved to have small time constants and sufficient long term stability.…”

Section: Introductionmentioning

confidence: 99%

“…The sample loop was filled with a syringe. As stated earlier [23][24][25] these are optimized conditions to titrate acids and bases with a satisfying sample frequency. Chronopotentiometric measurements were recorded using an AUTOLAB with a PSTAT 10 (Eco-Chemie, The Netherlands) in conjunction with a personal computer (IBM compatible).…”

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confidence: 99%

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Rapid Automatic Determination of Calcium and Magnesium in Aqueous Solutions by FIA Using Potentiometric Detection

2010

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A pH-sensitive detector for flow-through potentiometry based on a graphite/quinhydrone/silicone composite electrode was applied to determine calcium and magnesium in aqueous solutions. The determinations are performed by FIA titrations with EDTA as the carrier solution. The method was applied to the analysis of mineral water, drinking water, and river water. The results were compared with those obtained by batch complexometric titration. The proposed new method is suitable for the simple, rapid and automated determination of water hardness in small sample volumes of aqueous solutions. The detection limit for both ions is about 1 10 À5 mol L À1 , the standard deviation is less than 2%. The sampling frequency is 60 determinations per hour.

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Section: The Fia Titration Systemmentioning

confidence: 99%

Section: The Fia Titration Systemmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Rapid Automatic Determination of Calcium and Magnesium in Aqueous Solutions by FIA Using Potentiometric Detection

2010

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“…2 3 Regarding the possibilities of exploiting of injection techniques to improve titration, the most popular approach seems to be so-called gradient titration performed in flow injection systems. [4][5][6][7][8] Material and time could be saved by using flow injection titration to replace manual batch titration. Calatayud et al proposed a flow method for the titration of weak acids or weak bases using linear titration plots.…”

Section: Introductionmentioning

confidence: 99%

Determination of Base Composition Based on Flow Injection Analysis and Local Linear Embedding-Support Vector Regression Modeling Method

Ji¹,

Deng²

2012

Jnl of Comp & Theo Nano

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A flow injection analysis (FIA) method was used to determine the alkaline constituents in boil water. The FIA method was based on the injection of an alkaline sample into a carrier stream of a standard acid solution. The sample and reagent zones were partially mixed due to dispersion and thereby the sample was partially neutralized by the acid. A flat pH electrode was used to sense the output voltage of the mixture. The signal was recorded as a typical FIA peak. For the mixed base with the same composition, the FIA peak areas were experimentally found to be proportional to the logarithm of total basicity of mixed base. The composition of the mixed base could be determined by the pH and the FIA peak area. In case of Na 2 CO 3 and NaOH mixture, the concentration of NaOH could be directly obtained from the pH value of the solution, due to the fact that the pH of the mixture was mainly decided by the NaOH concentration. The total basicity could be determined by the corresponding calibration curve. The concentration of Na 2 CO 3 could be calculated by the concentration of NaOH and the total basicity of mixture. In order to get the better precision of the FIA method, a local linear embedding (LLE), coupled with support vector regression (SVR) modeling, is also proposed to determine the constituents of an alkaline mixture instead of the previous linear calibration curve. All the output voltage of the pH electrode, instead of the FIA peak areas, was used as the input of the LLE-SVR model. The logarithm of total basicity of mixed base was the output of the model. LLE is a nonlinear dimensionality reduction method, which is suitable for the data that lies on the nonlinear manifold and can reveal the global nonlinear structure by combining the local linear relationship. SVR is considered as a substitute for traditional learning regression approach and has the excellent generalization performance especially in small samples of the nonlinear case. Using LLE and SVR method (LLE-SVR) together to determine alkaline mixture can avoid disturbance from the unknown compositions. Relative standard deviation from the linear calibrating curve between the peak area and the logarithm of total basicity of mixed base was 2.34 percent. The proposed LLE-SVR modeling can decrease the calibrating error between the FIA peak areas and the total basicity. Prediction relative error of NaOH from LLE-SVR model and SVR model was 0.7224 and 1.1857 percent respectively. Prediction relative error of Na 2 CO 3 from LLE-SVR model and SVR model was 1.1864 and 1.6885 percent respectively. But the LLE-SVR and SVR had the more computation than the liner calibration curve.

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Application of High‐Throughput Screening in Biocatalysis

Ju¹,

Zhang

Chan³

et al. 2016

Applied Biocatalysis: From Fundamental Science to Industrial Applications

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A potential high-throughput method for the determination of lipase activity by potentiometric flow injection titrations

Cited by 8 publications

References 30 publications

Rapid Automatic Determination of Calcium and Magnesium in Aqueous Solutions by FIA Using Potentiometric Detection

Rapid Automatic Determination of Calcium and Magnesium in Aqueous Solutions by FIA Using Potentiometric Detection

Determination of Base Composition Based on Flow Injection Analysis and Local Linear Embedding-Support Vector Regression Modeling Method

Application of High‐Throughput Screening in Biocatalysis

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