Photometric Sensing of Active Chlorine, Total Chlorine, and pH on a Microfluidic Chip for Online Swimming Pool Monitoring

A microfluidic sensor was studied for the photometric detection of active chlorine, total chlorine, and pH in swimming pool samples. The sensor consisted of a four-layer borosilicate glass chip, containing a microchannel network and a 2.2 mm path length, 1.7 mL optical cell. The chip was optimised to measure the bleaching of methyl orange and spectral changes in phenol red for quantitative chlorine (active and total) and pH measurements that were suited to swimming pool monitoring. Reagent consumption (60 mL per measurement) was minimised to allow for maintenance-free operation over a nominal summer season (3 months) with minimal waste. The chip was tested using samples from 12 domestic, public, and commercial swimming pools (indoor and outdoor), with results that compare favourably with commercial products (test strips and the N,N’-diethyl-p-phenylenediamine (DPD) method), precision pH electrodes, and iodometric titration.

Ex-vivo Electrochemical pH Mapping of the Gastrointestinal Tract in the Absence and Presence of Pharmacological Agents

<i>Ex-vivo</i> pH profiling of the upper gastrointestinal (GI) tract (of a mouse) in both the absence and presence of pharmacological agents aimed at altering acid/bicarbonate production, is reported using an electrochemical pH probe, for the first time. Three pH electrodes were assessed for suitability using a GI tract biological mimic buffer solution containing 0.5 % mucin. These include a traditional glass pH probe, an iridium oxide (IrOx) coated electrode (both potentiometric) and a quinone (Q) surface-integrated boron doped diamond (BDD-Q) electrode (voltammetric). In mucin the timescale for both IrOx and glass to obtain stable pH readings was in the ~100’s of s, most likely due to mucin adsorption, in contrast to 6 s with the BDD-Q electrode. Both the glass and IrOx pH electrodes were also compromised on robustness due to fragility and delamination (IrOx); contact with the GI tissue was an experimental requirement. BDD-Q was deemed the most appropriate. Ten measurements were made along the GI tract, esophagus (1), stomach (5) and duodenum (4). Under untreated conditions (buffer only), the BDD-Q probe tracked the pH from neutral in the esophagus, to acidic in the stomach and rising to more alkaline in the duodenum. In the presence of omeprazole, a proton pump inhibitor, the body regions of the stomach exhibited elevated pH levels. Under melatonin treatment (a bicarbonate agonist and acid inhibitor), both the body of the stomach and the duodenum showed elevated pH levels. This study demonstrates the versatility of the BDD-Q pH electrode for real-time <i>ex-vivo</i> biological tissue measurements.

Ex-vivo Electrochemical pH Mapping of the Gastrointestinal Tract in the Absence and Presence of Pharmacological Agents

<i>Ex-vivo</i> pH profiling of the upper gastrointestinal (GI) tract (of a mouse) in both the absence and presence of pharmacological agents aimed at altering acid/bicarbonate production, is reported using an electrochemical pH probe, for the first time. Three pH electrodes were assessed for suitability using a GI tract biological mimic buffer solution containing 0.5 % mucin. These include a traditional glass pH probe, an iridium oxide (IrOx) coated electrode (both potentiometric) and a quinone (Q) surface-integrated boron doped diamond (BDD-Q) electrode (voltammetric). In mucin the timescale for both IrOx and glass to obtain stable pH readings was in the ~100’s of s, most likely due to mucin adsorption, in contrast to 6 s with the BDD-Q electrode. Both the glass and IrOx pH electrodes were also compromised on robustness due to fragility and delamination (IrOx); contact with the GI tissue was an experimental requirement. BDD-Q was deemed the most appropriate. Ten measurements were made along the GI tract, esophagus (1), stomach (5) and duodenum (4). Under untreated conditions (buffer only), the BDD-Q probe tracked the pH from neutral in the esophagus, to acidic in the stomach and rising to more alkaline in the duodenum. In the presence of omeprazole, a proton pump inhibitor, the body regions of the stomach exhibited elevated pH levels. Under melatonin treatment (a bicarbonate agonist and acid inhibitor), both the body of the stomach and the duodenum showed elevated pH levels. This study demonstrates the versatility of the BDD-Q pH electrode for real-time <i>ex-vivo</i> biological tissue measurements.

A framework for plant growth analysis and simulation using data analysis techniques

PurposeIn India, agriculture is considered as the major source of income for a major sector of people. Our country's GDP (Gross Domestic Product) can increase only if we focus on agriculture and its growth toward global economy. There have been several attempts to improve the agricultural sector since decades.Design/methodology/approachThis work describes about the design of a device which continuously monitors the plant growth and sends the data to a centralized database, where data is dynamically analyzed based on base references using various machine learning algorithms like regression, gradient descent, clustering etc.FindingsThis paper aims at analyzing the plant growth in of our country and focuses on the improvement of plant growth based on factors such as temperature, air moisture, radiant energy, carbon dioxide levels, soil pH& temperature through the design of a device.Originality/valueIt is anticipated to provide a solution by analyzing the plant growth percentage in different regions over a period of time. Based on the inferences, we will be able to suggest an optimum environment for the plant species to grow best. Various sensors like temperature and humidity sensors, light sensors and pH electrodes can be used in collecting data from the plant environment.