A novel method based on conversion of chlorinatedvolatile organic compounds (CVOCs) to chlorine using anew type of column packed with nanometer TiO2 coupledwith chemiluminescence (CL) has been developed fordetermination of them in workplace air. CVOCs areconverted to chlorine by nanometer TiO2 at 220℃. TheCl2 that is produced is selectively enriched on the columnand subsequently released from the column at 600℃. The Cl2 that is released is determined using a postcolumnCL detector. The CL intensity was linear with CCl4 in therange of 0.1-380 ppm, and the detection limit was 40ppb (S/N) 3). Higher sensitivity could be acquired byusing a larger volume of enrichment. A similar procedurecould be used for the determination of other CVOCs. CLintensities of CH2Cl2, CHCl3, and CCl4 at the sameconcentration increased in the order CH2Cl2<CHCl3<CCl4. The method has been successfully applied to thedetermination of CCl4 in workplace air, where 0.15-150ppm CCl4 would be detected. The possible mechanismfor the long lifetime of the column packed with nanometerTiO2 was tested using Raman spectrometer, X-ray powderdiffraction, transmission electron microscopy and X-rayphotoelectron spectroscopy. The results showed that thecolumn packed with nanometer TiO2 could be operatedin the reversible mode for determination of CVOCs underthe present conditions. The method would be potentiallyapplied to the analysis of other chlorinated compoundsin environment, such as persistent organic pollutants.

A gas-sensing mode based on chemiluminescence generatedon the surface of nanosized materials is proposed inthe present work. Seven nanosized materials were tested, and chemiluminescence was detected from six of themduring the catalytic oxidation of organic vapors in air. The luminescence characteristics of ethanol and acetonevapors passing through the surface of TiO2 chosen werestudied with a chemiluminescence-based detection system.The linear range of chemiluminescence intensityversus concentration of organic compounds is 40-400µg/mL for ethanol and 20-200µg/mL for acetone dissolvedin water, respectively. X-ray powder diffraction andRaman spectrometry were used to investigate the changesin catalytic activity of TiO2 after a 60-h reaction at 380℃. The results showed that the carbon deposited on thesurface of TiO2, decreasing the catalytic activity, but canbe removed in air by controlling the temperature at 500℃ for 3h. Regenerability and no consumption of sensorsubstrate signify the long lifetime of the gas sensor.

In the present report, thirty different types of Chinese edible seafood, including brown algae, red algae, fish, crab, shrimp, mussels, oysters, and clams, which are very popular foodstuffs in the Chinese kitchen, were examined for their total content of As aswell as its different species. Total arsenic concentration in algae samples was 1.7-38.7

When reductive gases pass over the surface of nanosized catalysts, a kind of chemiluminescence named cataluminescence (CTL) canbe generated due to the production of excited intermediates. Here we report the observation of an energy transfer process between excitedintermediates and the nanosized catalysts. The CTL is quenched when introducing Ho3+, Co2+ and Cu2+ into the catalyst, while new intensiveCTL peaks appear when the catalyst is doped with Eu3+ or Tb3+. Further study indicates that the new CTL peak on Eu3+-or Tb3+-dopedcatalyst originates from the luminescence of the doped ions, excited by the energy transferred from excited intermediates produced during thereaction. Based on this novel energy-transfer CTL (ETCTL), an ethanol sensor is developed with Eu3+-doped nanosized ZrO2 that is linear toethanol concentrations from 45 to 550 ppm, with the whole linear range lower than the lower limit of the previous CTL sensor. The ETCTLfrom Eu3+-doped in nanosized ZrO2 shows 72 times higher sensitivity than the CTL from excited intermediates in the sensor. High selectivityand stability are also obtained for this sensor. The results also indicate that the main factor limiting the sensitivity of CTL sensor on purecatalyst may be the inevitable energy quenching of excited intermediates with the catalyst, which is artfully utilized in the present work bythe introduction of Eu3+ that effectively absorbs this part of energy and transfers it into light energy.

Background: An inductively coupled plasma mass spectrometry (ICP-MS)-based immunoassay has been proposedindependently by Baranov et al. (Anal Chem2002; 74: 1629-36) and our group, but the applicability ofthis method for multianalyte analysis in clinical sampleshas not been fully illustrated. We developed adual-label immunoassay method for the simultaneousdetermination of β-fetoprotein (AFP) and free β-humanchorionic gonadotropin (hCGβ) in human serum.Methods: Monoclonal antibodies immobilized on microtiterplates captured AFP and hCGβ, which weredetected by use of Eu3+-labeled anti-AFP and Sm3+-labeled anti-hCGβmonoclonal antibodies. Eu3+andSm3+were dissociated from the immunocomplex withHNO3 solution (10mL/L) and delivered by peristalticpump to the ICP mass spectrometer.Results: The measurable ranges of AFP and hCG+were4.6-500 and 5.0-170 ug/L, respectively, with detectionlimits of 1.2 and 1.7ug/L (3SD above mean of zerocalibrator), respectively. The intraassay imprecision (CV) for AFP was 8.3%, 4.0%, and 2.7% at 16.3, 86, and 354ug/L, respectively, and the interassay CV was 10%, 5.7%, and 3.5%. For hCGβ, the intraassay CV was 5.4%, 6.4%, and 3.1%, respectively, at 10.5, 45.2, and 105ug/L, and the interassay CV was 7.2%, 8.0%, and 3.7%. Comparisonwith IRMAs for AFP and hCGβyielded correlationcoefficients (r2) of 0.97 and 0.95.Conclusions: Two proteins can be measured simultaneouslyby immunoassays using two rare earth elementaltags (Eu3+and Sm3+) and ICP-MS detection. Themultielement capability and the multiple potential elementallabels make ICP-MS attractive for multianalyteimmunoassays. Implementation of ICP-MS-linked immunoassaysmay be relatively straightforward becausethe labeling and immunoreaction procedures have beenwell developed for clinical time-resolved immunofluorometricassays.