The Characterization of a Custom-Built Coulometric Karl Fischer Titration Apparatus

Abstract

The instrumentation found in laboratories today is unaffordable for many secondary schools and universities. Although most analytical chemistry curricula at the undergraduate level teach students the principles behind modern instruments, few courses are able to incorporate them into a laboratory setting, thus preventing many science and engineering students from attaining valuable work experience with the equipment they may one day use. This dilemma led our research group to focus on developing inexpensive small-scale instruments. One such device we have produced is a Karl Fischer coulometric titrator. Karl Fischer (KF) titration is a widely used analytical technique for the quantification of water in various substances including laboratory solvents, transformer oils, pharmaceuticals, cosmetics, and food products. This method of titration is carried out within a bipotentiometric cell, where the water content of a sample is quantified based on the number of electrons transferred during titration. Our aim was to develop a low-cost, custom-built KF titration apparatus that facilitates the practical application of KF analysis within standard undergraduate general and analytical chemistry laboratory courses.

Analysis of water in room temperature ionic liquids by linear sweep, differential pulse and square wave cathodic stripping voltammetries

“…The Karl Fischer titrations (KFT) were performed using a custom-built KF titrator [26,33]. The cell consists of a 100 mL beaker with a 4-hole rubber stopper.…”

“…The detector electrode system comprised two straight Pt wires since a bipotentiometric end-point detection method was used [34]. The accuracy and efficiency of this KF equipment were tested using small additions (1-5 mL) of Type 1 water into the anolyte compartment, finding a total recovery of 100.2 AE 1.7 %, with a minimum detectable volume (MDV) [33] slightly less than 0.01 mL of water and a lower limit of quantitation (LOQ) of 0.34 mL, values that compare well with those reported for commercial instruments.…”

Integrating Chemistry Laboratory Instrumentation into the Industrial Internet: Building, Programming, and Experimenting with an Automatic Titrator

“…Excellent examples of novel laboratory experiments designed to address this problem have been published in this Journal. 11,12 In the present experiment, students use state-of-the-art microcontroller hardware and an open-source software platform to build and operate chemistry laboratory equipment. Additionally, the integration of laboratory instrumentation into the Internet opens many opportunities for remote control of the instrumentation and further developments of new laboratory units.…”

“…Too often, the actual chemical processes are hidden, and instruments seem to operate “magically”. , In this highly technological era, it is crucial that students understand the electronic components required for the instrumentation to work as well as the chemical explanations. Excellent examples of novel laboratory experiments designed to address this problem have been published in this Journal . , …”

Autonomous Titration for Chemistry Classrooms: Preparing Students for Digitized Chemistry Laboratories

“…32 In this work, we describe a set of classroom activities that are designed to address the changing skill requirements bridging chemistry, engineering and computer science. Specifically, the project aims to design a robotic platform for autonomous titration, a common experiment for high school and undergraduate education, [33][34][35][36] and can thus be readily integrated into existing curricula. Several classroom experiments focusing on automated titrations have recently been introduced.…”