S.B.Gamagedara & A.N.Navaratne Department of Chemistry, Faculty of Science, University of Peradeniya, Peradeniya, Sri Lanka. Abstract Oxyfluorfen [2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl) benzene] is a selective pre and post emergence diphenyl-ether herbicide used to control certain annual broadleaf and grassy weeds in vegetables, fruit, cotton, ornamentals and rice. Here we report the use of a non electroactive stearic acid modified glassy carbon electrode as an amperometric sensor for the detection of Oxyfluorfen. Preliminary electrochemical characterization was done by cyclic voltammetry. Analytical characteristics of the sensor was evaluated by steady state amperometry. Cyclic voltammetric experiments of 0.1mM Oxyfluorfen in an ethanol water (4:6) mixed solution of 0.1M NaCl showed two reduction peaks at potentials of -0.39V and -0.80V, vs saturated calomel reference electrode. Oxidation peak was obtained at -0.28V. Scan rate dependence studies of the peak at -0.15 V vs saturated calomel electrode show that it is a diffusion control reaction. The potential of the working electrode was optimized and the optimum operational potential for the amperometric experiments was found to be -0.800 V and -0.900 V with respect to the saturated calomel electrode. The amperometric measurements at the above potentials suffered interference from the noise with the sequential addition of Oxyfluorfen at bare glassy carbon electrode. This difficulty was overcome by modifying the electrode surface with a suitable modifier. In this study non electro active stearic acid (0.5% w/v) was used as the electrode modifier. When stearic acid was deposited on the electrode surface noise levels of the amperometric results were substantially reduced. This may due to prevention of adsorption of the analyte molecules on the electrode surface and an uniform electron transfer mechanism. Slopes of calibration curves were taken as the sensitivities of the sensor. At -0.800V potential slope is 9.828x105 μAmol-1dm3 and at -0.900V potential slope is 1.1982x106 μAmol-1dm3. Signal to Noise ratio was calculated to be 7.00. The steady state amperometric response time (t-90) of the sensor was 6.3 sec. The coefficient of variation of the sensor was estimated to be 13.2%. Since the problematic noise levels can be successfully overcome by stearic acid coated glassy carbon electrode, this study demonstrates the potential utility of the sensor as an amperometric detector for Oxyfluorfen. S.B.Gamagedara, A.N.Navaratne “An Electroanalytical Sensor for detection of Oxyfluorfen (Goal)”; Sri lanka Association for the Advancement of Science,Proc.62nd Annual Sessions, Colombo,Sri Lanka, December 2006.

There are a lot of chemicals racing around your brain and body when you're in love. That initial giddiness that comes when we're first falling in love includes a racing heart, flushed skin and sweaty palms. Researchers say this is due to the dopamine, norepinephrine and phenylethylamine we're releasing. Dopamine is thought to be the "pleasure chemical," producing a feeling of bliss. Norepinephrine is similar to adrenaline and produces the racing heart and excitement. These two chemicals produce elation, intense energy, sleeplessness, craving, loss of appetite and focused attention. The brain scans showed increased blood flow in areas of the brain with high concentrations of receptors for dopamine associated with states of euphoria, craving and addiction. High levels of dopamine are also associated with norepinephrine, which heightens attention, short-term memory, hyperactivity, sleeplessness and goal-oriented behavior. In other words, couples in this stage of love focus intently on the relationship and often on little else. People in love have lower levels of serotonin and also that neural circuits associated with the way we assess others are suppressed. Vasopressin, an antidiuretic hormone, is another chemical that has been associated with the formation of long-term, monogamous relationships. Endorphins, the body's natural painkillers, also play a key role in long-term relationships. They produce a general sense of well-being, including feeling soothed, peaceful and secure. The feelings of passionate love, however, do lose their strength over time. Studies have shown that passionate love fades quickly and is nearly gone after two or three years. The chemicals responsible for "that lovin' feeling" (adrenaline, dopamine, norepinephrine, phenylethylamine, etc.) dwindle. Suddenly your lover has faults. Why has he or she changed, you may wonder. Actually, your partner probably hasn't changed at all; it's just that you're now able to see him or her rationally, rather than through the blinding hormones of infatuation and passionate love. At this stage, the relationship is either strong enough to endure, or the relationship ends. References: http://people.howstuffworks.com/love6.htm

The massive amount of processing power generated by computer manufacturers has not yet been able to satisfy our need for speed and computing capacity. According to Moore's Law the number of transistors on a microprocessor continues to double every 18 months. So next generation computers will be quantum computers, which harness the power of atoms and molecules to perform memory and processing tasks. Quantum computers have the potential to perform certain calculations billions of times faster than any silicon-based computer. Paul Benioff was the first person who applied the quantum theory to computers in 1981and it was based on Turing Theory. Today's computers, like a Turing machine, work by manipulating bits that exist in one of two states: a 0 or a 1. Quantum computers are not limited to two states; they encode information as quantum bits, or qubits. A qubit can be a 1 or a 0, or it can exist in a superposition that is simultaneously both 1 and 0 or somewhere in between. Qubits represent atoms that are working together to act as computer memory and a processor. Because a quantum computer can contain these multiple states simultaneously, it has the potential to be millions of times more powerful than today's most powerful supercomputers. This superposition of qubits is what gives quantum computers their inherent parallelism. Quantum computers also utilize another aspect of quantum mechanics known as entanglement. In quantum computers when you try to look at the subatomic particles, you could bump them. So their value changed. But in quantum physics, if you apply an outside force to two atoms, it can cause them to become entangled, and the second atom can take on the properties of the first atom. So if left alone, an atom will spin in all directions; but the instant it is disturbed it chooses one spin, or one value; and at the same time, the second entangled atom will choose an opposite spin, or value. We can use this to know the value of the qubits without actually looking at them, which would collapse them back into 1's or 0's.Other major advantage is not like the Binary Logic, the Quantum Logic is reversible. Currently the technology required to develop such a quantum computer is beyond our reach because most research in quantum computing is still very theoretical. Hope one day quantum computers will replace the silicon based computers.

The electronic nose recently developed by NASA Jet Propulsion Laboratory is based on a Polymer Carbon Sensing Array.It is designed to be used for Air Quality Monitoring in the space and to detect and identify common contaminants in the ppm range.It is consists of 32 conductometric sensors made from insulating polymer films loaded with carbon. In the current design it can detect 10 common contaminants which may be released into the re circulated breathing air of the space shuttle or space station from a spill or a leak. As in other array-based sensor devices, the individual sensor films of the ENose are not specific to any one analyte; it is in the use of an array of different sensor films that gases or gas mixtures can be uniquely identified by the pattern of measured response. So these complex response patterns require software analysis to identify the compounds and concentrations causing the response. Currently it can detect Ammonia, Benzene, Ethanol, Freon, Formaldehyde, Indole, Methane, Mathanol, Propanol,Toluene, Medical Wipe and Relative Humidity. The sensors in the ENose are thin films made from commercially available insulating polymers loaded with carbon black as a conductive medium, to make a polymer-carbon composite. A baseline resistance of each film is established; as the constituents in the air change, the films swell or contract in response to the new composition of the air, and the resistance changes. Sensing films were deposited on ceramic substrates which had eight Au-Pd electrode sets.Six different polymers were used to make sensing film; each polymer was used to make 2 sensors for a total of 32 sensors. I think we can modify this Electronic Nose to detect explosive materials and the Narcotic Drugs. Since the sensor array can detect air contaminants in parts per million range this would be very useful in security purposes in Air Ports. We modify the polymer that we are using and may be we can go even lower concentrations than this. So I hope one day guard dogs are replaced by these Electronic Noses.

Hi, I’m Sanjeewa Gamagedara. I have completed my BSc.(Hons) Chemistry Special degree (2002-2006) at the Faculty of Science, University of Peradeniya, Sri Lanka. Also I finished Advanced Diploma in Information Technology at the Sri Lanka Institute of Information Technology (SLIIT). I completed my primary and high school education at the Dharmaraja College, Kandy, Sri Lanka. Currently I'm working in the Temporary Academic Staff, Department of Chemistry,University of Peradeniya, Sri Lanka. For my Undergraduate degree I studied Chemistry, Physics, Molecular Biology & Biotechnology and specialized in Chemistry. From my childhood I had a innate interest in Science. As I look back, I was interested in Instruments and wanted to know how stuff works and what is in it.During my undergraduate studies I became interested in Analytical Chemistry, because of its Interdisciplinary Nature. For my Undergraduate Research I have developed an Electroanalytical Sensor for the detection of diphenyl ether herbicide, Oxyfluorfen. It was presented in a National Conference and Currently being reviewed for publish in an International Research Journal. I’m interested in Chemical Sensors, BioSensors, Miniaturized Sensing devices, Lab on Chips, Bioengineering Instrumentations and currently studying those sensors since we don’t have much facilities to continue research in those miniaturized systems here in Sri Lanka. Hope I will be able to continue my ideas when I’m doing my graduate studies. I use this Blog entry as a “Concept Nursery” to Incubate and share my ideas with the scientific community. Please feel free to add comments to this site. Also you can email me, email: sanjeewagamagedara@yahoo.com.

I have developed an Electroanalytical Sensor to detect Oxyfluorfen.This is a short description about Oxyfluorfen. Oxyfluorfen, the active ingredient of the herbicide Goal is a selective pre and post emergence diphenyl-ether herbicide used to control certain annual broadleaf and grassy weeds in vegetables, fruit, cotton, ornamentals and rice. It is a contact herbicide and light is required for it to affect target plants. Some other trade names include Goal2E, Koltar and RH-2915. It is available in emulsifiable concentrate and granular formulations. Oxyfluorfen is a white to orange or red-brown crystalline solid with a smoke-like odor. It may decompose if exposed to UV light. It is stable under normal temperatures and pressures, but poses a slight fire hazard if exposed to heat or flame, and a fire and explosion hazard in the presence of strong oxidizers. It may burn but will not readily ignite. It may form flammable or explosive dust-air mixtures. Avoid contact with strong oxidizers, excessive heat, sparks or open flame. Thermal decomposition may release highly toxic fumes of fluorides and chlorides and toxic oxides of nitrogen and carbon.Its IUPAC name is 2-Chloro-α,α,α-trifluoro-p-tolyl 3-ethoxy-4-nitrophenyl ether and Chemical Abstract name is 2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4 (trifluoromethyl) benzene. It has a molecular weight of 361.7 gmol-1. Its molecular formula is C15H11ClF3NO4 .

Electroanalytical chemistry can play a very important role in the protection of our environment. In particular, electrochemical sensors and detectors are very attractive for on-site monitoring of priority pollutants, as well as for addressing other environmental needs. Such devices satisfy many of the requirements for on-site environmental analysis. They are inherently sensitive and selective towards electroactive species, fast and accurate, compact, portable and inexpensive. Such capabilities have already made a significant impact on decentralized clinical analysis. Yet, despite their great potential for environmental monitoring, broad applications of electrochemical sensors for pollution control are still in their infancy. Several electrochemical devices, such as pH- or oxygen electrodes, have been used routinely for years in environmental analysis. Recent advances in electrochemical sensor technology will certainly expand the scope of these devices towards a wide range of organic and inorganic contaminants and will facilitate their role in field analysis. These advances include the introduction of modified- or ultramicroelectrodes, the design of highly selective chemical or biological recognition layers, of molecular devices or sensor arrays, and developments in the areas of microfabrication, computerized instrumentation and flow detectors.