An optical chemical sensor has been developed for the determination of iodine based on the reversible fluorescence quenching of 2, 2, 7, 7, 12, 12, 17, 17-octamethyl-21, 22, 23, 24-tetraoxaquaterene-Li （LiTOE） imm...An optical chemical sensor has been developed for the determination of iodine based on the reversible fluorescence quenching of 2, 2, 7, 7, 12, 12, 17, 17-octamethyl-21, 22, 23, 24-tetraoxaquaterene-Li （LiTOE） immobilized in a plasticized poly（vinyl chloride） （PVC） membrane. The optimum membrane of the sensor consists of 100 mg of PVC, 200 mg of bis （2-ethytbexyl） sebacate （BOS） and 3.0 mg of LiTOE. The maximum response of the optode membrane for iodine is obtained in Tris-HCl buffer solutlon （pH 8.0）. With the optimum conditions described, the proposed sensor responds linearly in the measuring range of 3.90×10^-2 to 3.90×10^-4 mol/L, and has a detection limit of 6.0×10^-8 mol/L. The response time of the sensor is less than I rain. In addition to high reproducibility and reversibility of the fluorescence signal, the sensor also exhibits good selectivity. It is not interfered by some common anions and cations. It is applied for the determination of iodine in table salt samples. The results agree with those obtained by another method.展开更多
Several organic polymers and sol-gel derived porous silica were investigated as cladding material of a fused silica optical fi ber as well as a solid phase microextraction (SPME) material in an eff ort to develop an e...Several organic polymers and sol-gel derived porous silica were investigated as cladding material of a fused silica optical fi ber as well as a solid phase microextraction (SPME) material in an eff ort to develop an evanescent wave optical fi ber chemical sensor (EW-OFCS) for detecting acetylsalicylic acid (ASA) in aqueous sample solutions.A dip-coating method was adopted for coating a polymer on the fi ber core surface of a bent optical fi ber probe (BOFP) as a cladding/SPME membrane.Among the polymers investigated,it was found that cellulose triacetate (CTA) can function as a SPME material for concentrating ASA from aqueous sample solution into CTA membrane coated on BOFP surface.The ASA concentrated into the CTA membrane was detected by passing a light beam through the BOFP and detecting the fi ber optic EW absorption signal at ASA’s intrinsic peak absorption wavelength (310 nm).No chemical reaction was involved in the developed sensor and no chemical reagent is needed in using the sensor for detecting ASA in an aqueous sample solution.The sensor response is reversible because SPME is a reversible process.This SPME-EW-OFCS achieved a detection limit of 0.72μg/mL for detecting ASA in aqueous sample solutions.The sensor has been used for analyzing ASA in pharmaceutical Aspirin products,and obtained analytical results agree well with a conventional UV/Vis absorption spectrometric method.展开更多
A low-cost and portable optical chemical sensor based ammonia sensing system that is capable of detecting dissolved ammonia up to 5 ppm is presented. In the system, an optical chemical sensor is designed and fabricate...A low-cost and portable optical chemical sensor based ammonia sensing system that is capable of detecting dissolved ammonia up to 5 ppm is presented. In the system, an optical chemical sensor is designed and fabricated for sensing dissolved ammonia concentrations. The sensor uses eosin as the fluorescence dye which is immobilized on the glass substrate by a gas-permeable protection layer. A compact module is developed to hold the optical components, and a battery powered micro-controller system is designed to read out and process the data measured. The system operates without the requirement of laboratory instruments that makes it cost effective and highly portable. Moreover, the calculated results in the system can be transmitted to a PC wirelessly, which allows the remote and real-time monitoring of dissolved ammonia.展开更多
Quantum communication is a new technology requiring a stable and reliable laser source for communication security. A new kind of polarization-locked vertical-cavity surface-emitting laser （VCSEL） with polarization m...Quantum communication is a new technology requiring a stable and reliable laser source for communication security. A new kind of polarization-locked vertical-cavity surface-emitting laser （VCSEL） with polarization maintaining （PM） fiber pigtail is fabricated as a decoy state laser source. The VCSEL is packaged in a standard butterfly box integrated with thermoelectric coder （TEC） and thermistor. The optical pulse width of full-width at half-maximum （FWHM） is smaller than 400 ps with a 100-MHz on/off modulation frequency. The results reveal that modulation range is better than 4. Moreover, the polarization is stable, and the power extinction ratio is larger than 25. The center wavelength is 850 nm, and the SMSR is better than 40 dB.展开更多
文摘An optical chemical sensor has been developed for the determination of iodine based on the reversible fluorescence quenching of 2, 2, 7, 7, 12, 12, 17, 17-octamethyl-21, 22, 23, 24-tetraoxaquaterene-Li （LiTOE） immobilized in a plasticized poly（vinyl chloride） （PVC） membrane. The optimum membrane of the sensor consists of 100 mg of PVC, 200 mg of bis （2-ethytbexyl） sebacate （BOS） and 3.0 mg of LiTOE. The maximum response of the optode membrane for iodine is obtained in Tris-HCl buffer solutlon （pH 8.0）. With the optimum conditions described, the proposed sensor responds linearly in the measuring range of 3.90×10^-2 to 3.90×10^-4 mol/L, and has a detection limit of 6.0×10^-8 mol/L. The response time of the sensor is less than I rain. In addition to high reproducibility and reversibility of the fluorescence signal, the sensor also exhibits good selectivity. It is not interfered by some common anions and cations. It is applied for the determination of iodine in table salt samples. The results agree with those obtained by another method.
基金West Texas A&M University Killgore Research Grant。
文摘Several organic polymers and sol-gel derived porous silica were investigated as cladding material of a fused silica optical fi ber as well as a solid phase microextraction (SPME) material in an eff ort to develop an evanescent wave optical fi ber chemical sensor (EW-OFCS) for detecting acetylsalicylic acid (ASA) in aqueous sample solutions.A dip-coating method was adopted for coating a polymer on the fi ber core surface of a bent optical fi ber probe (BOFP) as a cladding/SPME membrane.Among the polymers investigated,it was found that cellulose triacetate (CTA) can function as a SPME material for concentrating ASA from aqueous sample solution into CTA membrane coated on BOFP surface.The ASA concentrated into the CTA membrane was detected by passing a light beam through the BOFP and detecting the fi ber optic EW absorption signal at ASA’s intrinsic peak absorption wavelength (310 nm).No chemical reaction was involved in the developed sensor and no chemical reagent is needed in using the sensor for detecting ASA in an aqueous sample solution.The sensor response is reversible because SPME is a reversible process.This SPME-EW-OFCS achieved a detection limit of 0.72μg/mL for detecting ASA in aqueous sample solutions.The sensor has been used for analyzing ASA in pharmaceutical Aspirin products,and obtained analytical results agree well with a conventional UV/Vis absorption spectrometric method.
基金This work was supported by Enterprise Ireland （El） and Science Foundation Ireland （SFI）. The authors would like to thank Pat O＇Leary from Faaltech Technologies Ltd and Jean-Michel Rubillon from Cork Institute of Technology for their support and help.
文摘A low-cost and portable optical chemical sensor based ammonia sensing system that is capable of detecting dissolved ammonia up to 5 ppm is presented. In the system, an optical chemical sensor is designed and fabricated for sensing dissolved ammonia concentrations. The sensor uses eosin as the fluorescence dye which is immobilized on the glass substrate by a gas-permeable protection layer. A compact module is developed to hold the optical components, and a battery powered micro-controller system is designed to read out and process the data measured. The system operates without the requirement of laboratory instruments that makes it cost effective and highly portable. Moreover, the calculated results in the system can be transmitted to a PC wirelessly, which allows the remote and real-time monitoring of dissolved ammonia.
文摘Quantum communication is a new technology requiring a stable and reliable laser source for communication security. A new kind of polarization-locked vertical-cavity surface-emitting laser （VCSEL） with polarization maintaining （PM） fiber pigtail is fabricated as a decoy state laser source. The VCSEL is packaged in a standard butterfly box integrated with thermoelectric coder （TEC） and thermistor. The optical pulse width of full-width at half-maximum （FWHM） is smaller than 400 ps with a 100-MHz on/off modulation frequency. The results reveal that modulation range is better than 4. Moreover, the polarization is stable, and the power extinction ratio is larger than 25. The center wavelength is 850 nm, and the SMSR is better than 40 dB.
