Measurement of transmembrane proton diffusion using two liposome-sequestered pH indicator dyes

1980 ◽  
Vol 93 (1) ◽  
pp. 326-332 ◽  
Author(s):  
William Stillwell ◽  
Keith Doram
Keyword(s):  
Ph Indicator ◽  
Proton Diffusion ◽  
Indicator Dyes

scholarly journals Impact of impurities in bromocresol green indicator dye on spectrophotometric total alkalinity measurements

2020 ◽  
Author(s):  
Katharina Seelmann ◽  
Martha Gledhill ◽  
Steffen Aßmann ◽  
Arne Körtzinger
Keyword(s):  
High Performance ◽  
Total Alkalinity ◽  
Bromocresol Green ◽  
Ph Indicator ◽  
Purification Method ◽  
Common Technique ◽  
Drift Behavior ◽  
Indicator Dyes ◽  
Indicator Dye

Abstract. Due to its accurate and precise character, the spectrophotometric pH detection is a common technique applied in measurement methods for carbonate system parameters. However, impurities in the used pH indicator dyes can influence the measurements quality. The work described here focuses on influences from impurities in the pH indicator dye bromocresol green (BCG) on spectrophotometric seawater total alkalinity (AT) measurements. First, a high-performance liquid chromatography (HPLC) purification method for BCG was developed. A subsequent analysis of BCG dye from four different vendors with this method revealed different types and quantities of impurities. After successful purification, AT measurements with purified and unpurified BCG were carried out using the novel autonomous analyzer CONTROS HydroFIA® TA. Long-term measurements in the laboratory revealed a direct influence of impurity types and quantities on the drift behavior of the analyzer. The purer the BCG, the smaller was the drift increment per measurement. Furthermore, we could show that a certain impurity in some indicator dyes changed the drift pattern from linear to non-linear, which can impair the AT measurements during a long-term deployment of the system. Laboratory performance characterization experiments revealed no improvement of the measurement quality (precision and accuracy) by using purified BCG as long as the impurities of the unpurified dye do not exceed a quantity of 2 % (relationship of peak areas in the chromatogram). However, BCG with impurity quantities higher than 6 % provided AT values, which failed fundamental quality requirements. Concluding, to gain optimal AT measurements, an indicator purification is not necessarily required as long as the purchased dye has a purity level of at least 98 %.

scholarly journals Impact of impurities in bromocresol green indicator dye on spectrophotometric total alkalinity measurements

Ocean Science ◽  
2020 ◽  
Vol 16 (2) ◽  
pp. 535-544
Author(s):  
Katharina Seelmann ◽  
Martha Gledhill ◽  
Steffen Aßmann ◽  
Arne Körtzinger
Keyword(s):  
High Performance ◽  
Total Alkalinity ◽  
Bromocresol Green ◽  
Ph Indicator ◽  
Purification Method ◽  
Common Technique ◽  
Drift Behavior ◽  
Indicator Dyes ◽  
Indicator Dye

Abstract. Due to its accurate and precise character, spectrophotometric pH detection is a common technique applied in measurement methods for carbonate system parameters. However, impurities in the used pH indicator dyes can influence the measurements quality. During our work described here, we focused on impacts of impurities in the pH indicator dye bromocresol green (BCG) on spectrophotometric seawater total alkalinity (AT) measurements. In order to evaluate the extent of such influences, purified BCG served as a reference. First, a high-performance liquid chromatography (HPLC) purification method for BCG was developed as such a method did not exist at the time of this study. An analysis of BCG dye from four different vendors with this method revealed different types and quantities of impurities. After successful purification, AT measurements with purified and unpurified BCG were carried out using the novel autonomous analyzer CONTROS HydroFIA® TA. Long-term measurements in the laboratory revealed a direct influence of impurity types and quantities on the drift behavior of the analyzer. The purer the BCG, the smaller was the AT increase per measurement. The observed drift is generally caused by deposits in the optical pathway mainly generated by the impurities. However, the analyzers drift behavior could not be fully overcome. Furthermore, we could show that a certain impurity type in some indicator dyes changed the drift pattern from linear to nonlinear, which can impair long-term deployments of the system. Consequently, such indicators are impractical for these applications. Laboratory performance characterization experiments revealed no improvement of the measurement quality (precision and bias) by using purified BCG as long as the impurities of the unpurified dye do not exceed a quantity of 2 % (relationship of peak areas in the chromatogram). However, BCG with impurity quantities higher than 6 % provided AT values which failed fundamental quality requirements. In conclusion, to gain optimal AT measurements especially during long-term deployments, an indicator purification is not necessarily required as long as the purchased dye has a purity level of at least 98 % and is free of the named impurity type. Consequently, high-quality AT measurements do not require pure but the purest BCG that is purchasable.

The Use of pH-indicator Dyes for pH-sensitive Textile Materials

2009 ◽  
Vol 80 (7) ◽  
pp. 590-603 ◽  
Author(s):  
L. Van der Schueren ◽  
K. De Clerck
Keyword(s):  
Ph Sensitive ◽  
Ph Indicator ◽  
Textile Materials ◽  
Indicator Dyes

scholarly journals Mass spectra of sulfonephthalein pH indicator dyes and their impurities

2017 ◽  
Vol 122 ◽  
Author(s):  
Regina A. Easley ◽  
Benjamin J. Place
Keyword(s):  
Mass Spectrometry ◽  
Bromothymol Blue ◽  
Synthesis Process ◽  
Thymol Blue ◽  
Bromocresol Green ◽  
Bromocresol Purple ◽  
Phenol Red ◽  
Ph Indicator ◽  
Ph Measurements ◽  
Indicator Dyes

Sulfonephthalein pH indicator dyes have historically been noted for impurities originating from the synthesis process, which lead to batch to batch differences in pH measurements. Uncertainties up to 0.1 pH units have been attributed to impurities in these reagents. In an effort to understand the extent of impurities in these dyes and the potential impact on the expanded uncertainty of spectrophotometric pH measurements, we have examined seven commercially available sulfonephthalein pH indicators using liquid chromatography-mass spectrometry (LC-MS): bromocresol green (BCG), bromocresol purple (BCP), bromothymol blue (BTB), cresol red (CR), meta-cresol purple (MCP), phenol red (PR), and thymol blue (TB). Peaks eluting from the LC were subjected to fragmentation by mass spectrometry. The resulting dataset will aid in efforts to improve the synthesis or purification of these dyes.

Novel pH indicator dyes for array preparation via NHS ester activation or solid-phase organic synthesis

2008 ◽  
Vol 6 (23) ◽  
pp. 4319 ◽  
Author(s):  
Sabine Trupp ◽  
Patrick Hoffmann ◽  
Thomas Henkel ◽  
Gerhard J. Mohr
Keyword(s):  
Organic Synthesis ◽  
Solid Phase ◽  
Ph Indicator ◽  
Solid Phase Organic Synthesis ◽  
Indicator Dyes

Spectroscopic Properties of Azobenzene-Based pH Indicator Dyes: A Quantum Chemical and Experimental Study

2011 ◽  
Vol 7 (4) ◽  
pp. 1062-1072 ◽  
Author(s):  
Daniel Escudero ◽  
Sabine Trupp ◽  
Beate Bussemer ◽  
Gerhard J. Mohr ◽  
Leticia González
Keyword(s):  
Experimental Study ◽  
Quantum Chemical ◽  
Spectroscopic Properties ◽  
Ph Indicator ◽  
Indicator Dyes
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