Research Article
Naphthalene Based Azo Dyes and Its Substituted Derivatives Containing Mono Boronic Acid - Saccharide Sensors
Issue:
Volume 14, Issue 2, June 2026
Pages:
18-27
Received:
14 March 2026
Accepted:
26 March 2026
Published:
13 April 2026
Abstract: Three novel naphthalene-based azo dyes incorporating boronic acid functional groups were synthesized. Their sugar-sensing behavior toward glucose and fructose was systematically investigated using UV-visible, fluorescence, time-resolved fluorescence, pH titration, and cyclic voltammetry techniques. Upon increasing the concentration of the sugars, both the absorbance and fluorescence intensities of the dyes decreased, indicating effective interaction. In the excited state, the dyes exhibited stronger sensing responses to fructose compared to glucose. The fluorescence lifetime measurements further confirmed the compounds' capability to detect sugars. At elevated pH levels, the boronic acid groups exist predominantly in their anionic form [B(OH)3-], which induces a change in the boron atom's hybridization from sp2 to sp3, facilitating binding with sugar molecules. Among the three compounds, compound 1 exhibited the highest association constant with fructose, suggesting a stronger binding affinity is higher than compared to glucose. To further validate the sugar-sensing behavior, the quantum yields of the compounds were measured in pure water, glucose, and fructose solutions. When higher concentrations of the sensor were introduced into the sugar solution, the oxidation peaks current (Ipa) decreased while the reduction peak current (Ipc) increased. In contrast, Ipa increased in the sensor-only solutions. Based on these observations, a plausible sensing mechanism has been proposed.
Abstract: Three novel naphthalene-based azo dyes incorporating boronic acid functional groups were synthesized. Their sugar-sensing behavior toward glucose and fructose was systematically investigated using UV-visible, fluorescence, time-resolved fluorescence, pH titration, and cyclic voltammetry techniques. Upon increasing the concentration of the sugars, b...
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Research Article
Assessment of Pesticide Contamination in Agricultural Soils According to Crop Type in the Niayes Zone
Marie Ndao
,
Alioune Badara Paye,
Adama Ndiaye,
Saliou Ngom,
Sokhna Ndao Diao,
Amadou Diop*
Issue:
Volume 14, Issue 2, June 2026
Pages:
28-35
Received:
22 May 2026
Accepted:
3 June 2026
Published:
23 June 2026
DOI:
10.11648/j.sjac.20261402.12
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Views:
Abstract: The Niayes constitute a unique ecosystem in Senegal, providing the bulk of the country's horticultural production. However, this area is undergoing severe ecological degradation due to the combined effects of several factors, including agricultural activities, urban and industrial development and climate change. Agriculture is becoming increasingly intensive, with high levels of chemical inputs, including pesticides. In 2021, studies showed that 100% of agricultural soils contained pesticides that could have harmful effects on soil health. Soil samples were taken in the study area in 2022 and 2023 and analyzed for residues of thirty-five pesticides, including persistent organic pollutants. The results obtained in 2022 revealed that 100% of the study sites were contaminated by pesticides, including profenofos (88% of plots), dimethoate (89%), bromacil and chlorpyrifos (64%) and abamectin (48%). The same trend was observed in 2023, when all sites were contaminated, with abamectin (89% of plots), cypermethrin, bromacil and profenofos (80%) the most frequently found molecules. These were followed by lambda-cyhalothrin, trifluralin and pendimethalin (76%), chlorpyrifos (71%), DDT (62%) and lindane (38%). These results were used to map contamination in the Niayes area in 2022 and 2023 using Geographic Information System (GIS) software, and to identify the most polluting crops. As a result, all soils hosting onions, carrots, turnips, peppers and tomatoes were contaminated. In addition, the highest pesticide residue levels were found in the soils of onion and tomato fields.
Abstract: The Niayes constitute a unique ecosystem in Senegal, providing the bulk of the country's horticultural production. However, this area is undergoing severe ecological degradation due to the combined effects of several factors, including agricultural activities, urban and industrial development and climate change. Agriculture is becoming increasingly...
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