A Novel Solid-State PVC-Membrane Potentiometric Dopamine-Selective Sensor Based on Molecular Imprinted Polymer.

A novel solid-state polyvinylchloride (PVC) membrane potentiometric dopamine-selective microsensor was constructed based upon dopamine-imprinted polymer used as the ionophore in the membrane structure. The optimum membrane composition was determined as 4% (w/w) MIP, 69% (w/w) bis(2-ethylhexyl) sebacate (DOS), 26% (w/w) PVC, and 1% (w/w) potassiumtetrakis(4-chlorophenyl) borate (KTpClPB). The detection limit of the microsensor was determined to be 3.71×10-7 mol.L-1. The microsensor exhibited a super-Nernstian response for dopamine over the concentration range of 10-6-10-1 mol.L-1, with a short response time (<15 s) and a slope of 60.3±1.3 mV per decade (R2: 0.9998) over seven weeks. The microsensor was effectively performed in a pH range of 4.0-8.0 and a temperature range of 5-30 °C. The microsensor has been successfully demonstrated for the rapid, accurate, selective and reproducible determination of dopamine in pharmaceutical formulations with the recovery of 104.3-104.8%. The obtained results were in good harmony with the UV-Vis results at a confidence level of 95%.

Cytological and histological effects of pesticide chlorpyriphos in the gills of Anabas testudineus.

The present study was aimed to report the toxicity of the chlorpyrifos, an organophosphorus insecticide, with regard to histological and cytological effects through light and transmission electron microscopes in the gills of freshwater fish, Anabas testudineus. The fish were exposed to 0.125 (5% of 96 h LC50), 0.250 (10% of 96 h LC50), and 0.375 mgL-1 (15% of 96 h LC50) of chlorpyrifos for 7, 14, and 21 days for light microscopy and 21 days for transmission electron microscopy. The histological effects were seen in all exposed concentrations of 0.125, 0.250, and 0.375 mgL-1. These effects increased with the increase in chlorpyrifos concentrations and duration of exposure. The main histological effects visible in the gill tissue were fusion of secondary lamellae and epithelial hyperplasia. Other effects included the epithelial hypertrophy, lifting of lamellar epithelium, aneurysm, necrosis, and desquamation of epithelial cells were also reported. Cytological effects included epithelial detachment, large subepithelial space, necrotic cells, apoptotic remnant of cells, the presence of macrophages, swelling of mitochondria in the chloride cells, distension of the tubular system, the presence of some large vacuoles, deposition of excessive mucous, and nucleus abnormalities. This study confirms that varying doses of chlorpyrifos have adverse histological and cytological effects in the gills of A. testudineus.