Absorbance based light emitting diode optical sensors and sensing devices

The ever increasing demand for in situ monitoring of health, environment and security has created a need for reliable, miniaturised sensing devices. To achieve this, appropriate analytical devices are required that possess operating characteristics of reliability, low power consumption, low cost, autonomous operation capability and compatibility with wireless communications systems. The use of light emitting diodes (LEDs) as light sources is one strategy, which has been successfully applied in chemical sensing. This paper summarises the development and advancement of LED based chemical sensors and sensing devices in terms of their configuration and application, with the focus on transmittance and reflectance absorptiometric measurements

Effect of vanadium on growth of Chinese green mustard (Brassica campestris ssp. chinensis var. parachinensis) under substrate culture

The effects of vanadium on growth of Chinese green mustard (Brassica campestris spp. var. parachinensis) and itsaccumulation in plant tissues were investigated. Substrate culture was set to grow the plants. Two weeks after planting, plantswere exposed for 3 weeks with a solution containing 6 different concentrations of ammonium metavanadate (0-80 mg/l).The results showed that stem length, number of leaves, and leaf and stem fresh weight of the plants treated with solutioncontaining 80 mg/l ammonium metavanadate were significantly lower than those of the plants treated with solutions of 0-40mg/l ammonium metavanadate. The vanadium accumulated in the plant tissues and substrates were determined by ioninteractionhigh performance liquid chromatography technique. Higher concentration of ammonium metavanadate appliedon plant, resulted on higher vanadium accumulated in tissues. Substrate, leaf and stem tissues of plants treated with 80 mg/lammonium metavanadate showed the highest accumulation of vanadium at 20.981, 1.658 and 2.046 mg/g, respectively