"Do-It-Yourself" reliable pH-stat device by using open-source software, inexpensive hardware and available laboratory equipment

Abstract

In this paper, we present the construction of a reliable and inexpensive pH stat device, by using open-source “OpenPhControl” software, inexpensive hardware (a peristaltic and a syringe pump, Arduino, a step motor…), readily available laboratory devices: a pH meter, a computer, a webcam, and some 3D printed parts. We provide a methodology for the design, development and test results of each part of the device, as well as of the entire system. In addition to dosing reagents by means of a low-cost peristaltic pump, we also present carefully controlled dosing of reagents by an open-source syringe pump. The upgrading of the basic open-source syringe pump is given in terms of pump control and application of a larger syringe. In addition to the basic functions of pH stat, i.e. pH value measurement and maintenance, an improvement allowing the device to be used for potentiometric titration has been made as well. We have demonstrated the device’s utility when applied for cellulose fibers oxidation with 2,2,6,6-tetramethylpiperidine-1-oxyl radical, i.e. for TEMPO-mediated oxidation. In support of this, we present the results obtained for the oxidation kinetics, the consumption of added reagent and experimental repeatability. Considering that the open-source scientific tools are available to everyone, and that researchers can construct and adjust the device according to their needs, as well as, that the total cost of the open-source pH stat device, excluding the existing laboratory equipment (pH meter, computer and glossary) was less than 150 EUR, we believe that, at a small fraction of the cost of available commercial offers, our open-source pH stat can significantly improve experimental work where the use of pH stat is necessary.

Arduino-based lab equipment: building a multipurpose pressure transducer device

“…However, many open-source micro-controllers and sensors are available at low cost for educational and recreational purposes: they do not require an academic-level knowledge of electronics or informatics, and they have been employed by researchers to set up many type of lab instruments [1][2][3][4].…”

Real-time water quality monitoring of an artificial lake using a portable, affordable, simple, Arduino-based open source sensor

“…However, free and opensource software (FOSS) is an available device, nowadays, that can pave the way for important measurements. FOSS is defined as computer software available in an open-source form, and that can be utilized, modified, and redistributed without any restriction (Milanovic et al 2018). These days, FOSS is becoming the norm in software evolution, with a variety of applications, including science and education , medicine (Lang 2011), engineering and nanotechnology (Pearce 2013).…”

“…Creating both software and hardware is feasible by a transparent system represented by FOSS and improving open-source hardware results in a significant cost reduction, enabling the state of the art scientific tools available all over the world (Pearce et al 2010). According to the literature, there are various open-source "do-it-yourself" devices, including: a potentiostat (Arevalo-Ramirez et al 2017), syringe pump (Wijnen et al 2014), a colorimeter (Anzalone et al 2013), pH-meter (Milanovic et al 2018) which can be provided by scientists with low costs. However, to our knowledge, the open-source device for measuring Turbidity, pH, and Temperature values has been provided in a notably smaller range (Garbacz et al 2013).…”

“…Using open-source hardware and software is one way to decrease the cost while still acquiring reliable assessment data. As a result, alternative methods which involve practical and cheaper testing platforms with multiple sensors were reported (Rao et al 2013;Kelley et al 2014;Wijnen et al 2014;Jin et al 2018;Milanovic et al 2018;Oelen et al 2018;Parra et al 2018). Rao et al 2013designed a continuous low-cost water quality monitoring system using an Arduino Mega 2560 to control six different sensors: temperature, light, pH, conductivity, dissolved oxygen, and oxidation-reduction potential.…”

“…Lopez-Ruiz et al (2014) determined the nitrite concentration and pH of water samples by using a low-cost, paper-based microfluidic device and used a smartphone as the light source and an image processing computer. Milanovic et al (2018) constructed a pH-stat device by using free and open source software and inexpensive hardware such as Arduino Nano and 3D-printed parts. Oelen et al (2018) controlled four different sensors with an Arduino board: a TDS (total dissolved solids), pH, turbidity, and temperature sensors.…”