Publication detail

Beyond Karl Fischer titration: a monolithic quantum cascade sensor for monitoring residual water concentration in solvents

PILAT, F. SCHWARZ, B. BAUMGARTNER, B. RISTANIC, D. DETZ, H. ANDREWS, A. LENDL, B. STRASSER, G. HINKOV, B.

Original Title

Beyond Karl Fischer titration: a monolithic quantum cascade sensor for monitoring residual water concentration in solvents

Type

journal article in Web of Science

Language

English

Original Abstract

Quality control of liquids is an important part of analytical chemistry. The gold standard for measuring residual water in organic solvents and pharmaceutical applications is Karl Fischer titration. It has a high sensitivity, selectivity and accuracy. The downsides are a time-consuming offline analysis, together with the need for toxic reagents producing waste, and it suffers from poor inter-laboratory reproducibility. In this work, we present a high-performance lab-on-a-chip sensor exploiting mid-IR spectroscopy for liquid sensing. It is operating at 6.1 mu m wavelength and is suitable for robust and flexible real-time in situ analysis of the residual water concentration in isopropyl alcohol. This is demonstrated in two experiments. A custom-made 60 mu L flow cell is employed to measure only minute amounts of analyte in an inline configuration. In a second approach, the whole sensor is immersed into the analyte to demonstrate sensitive and rapid in situ operation on the millisecond time scale. This is confirmed by the ability for time resolved single water-droplet monitoring, while they are mixed into the liquid sample. We obtain a limit of detection between 120 ppm and 150 ppm with a concentration coverage spanning three orders of magnitude from 1.2 x 10(-2)%(vol) to 25%(vol) for the flow cell and 1.5 x 10(-2)%(vol) to 19%(vol) in the in situ configuration, respectively.

Keywords

FT-IR; ORGANIC-SOLVENTS; WAVE-GUIDES; IN-VITRO; SPECTROSCOPY; TEMPERATURE; LASER

Authors

PILAT, F.; SCHWARZ, B.; BAUMGARTNER, B.; RISTANIC, D.; DETZ, H.; ANDREWS, A.; LENDL, B.; STRASSER, G.; HINKOV, B.

Released

28. 3. 2023

Publisher

Royal Society of Chemistry

Location

CAMBRIDGE

ISBN

1473-0189

Periodical

LAB ON A CHIP

Year of study

23

Number

7

State

United Kingdom of Great Britain and Northern Ireland

Pages from

1816

Pages to

1824

Pages count

9

URL

https://pubs.rsc.org/en/content/articlelanding/2023/LC/D2LC00724J

Full text in the Digital Library

http://hdl.handle.net/11012/213677

BibTex

@article{BUT183758,
  author="Florian {Pilat} and Benedikt {Schwarz} and Bettina {Baumgartner} and Daniela {Ristanic} and Hermann {Detz} and Aaron Maxwell {Andrews} and Bernhard {Lendl} and Gottfried {Strasser} and Borislav {Hinkov}",
  title="Beyond Karl Fischer titration: a monolithic quantum cascade sensor for monitoring residual water concentration in solvents",
  journal="LAB ON A CHIP",
  year="2023",
  volume="23",
  number="7",
  pages="1816--1824",
  doi="10.1039/d2lc00724j",
  issn="1473-0189",
  url="https://pubs.rsc.org/en/content/articlelanding/2023/LC/D2LC00724J"
}