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.

This paper describes the study of atomization of nanoparticlesby inductively coupled plasma mass spectrometry (ICPMS) and developes a novel nonisotopic immunoassayby coupling sandwich-type immunoreaction to ICPMS. The goat-anti-rabbit immunoglobulin G (IgG) labeled with colloidal gold nanoparticles served as ananalyte in ICPMS for the indirect measurement of rabbitanti-human IgG. Matrix effect studies showed the goldsignal was not sensitive to the organic matrix. A relativelygood correlation (r2=0.9528) between the proposedmethod and enzyme-linked immunosorbent assay hasbeen obtained. The method may have significant potentialas an important ICPMS-based nonisotopic immnoassaymethod for the simultaneous determination of biologicanalytes of interest by labeling different kinds of inorganicnanoparticles.

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.

To further expand the range of analytes that can be detected by using ICP-MS coupled with bioanalytical methods, we have employed a new separation system based on the highly active surface streptavidin and biotinylated monoclonal antibody (McAb) in a competitive immunoassay followed by ICP-MS detection. Specifically, we have demonstrated its application for the determination of total thyroxine (T4) in human serum using Eu31 as a label. In this method, streptavidin immobilized to the pre-coated bovine serum albumin (BSA)-biotin on the microwells showed a significantly higher binding capacity for the biotinylated anti-T4 monoclonal antibody. Total T4 was quantified by measuring the Eu31 intensity with ICP-MS after using 1% HNO3 to extract Eu31 from the bound fraction of the immunocomplex. The detection limit was 7.4ng mL-1 with a sample volume of 25

A study was carried out to determine arsenic species in Porphyra seaweed originating from the ChinaSea. Information about arsenic species in Porphyra was provided by HPLC-ICP-MS and ES-MSMS.The total arsenic concentrations of Porphyra samples from five different producing areas rangedfrom 2.1 to 21.6mg/kg. The analysis report also showed that arsenosugars were the only arsenicspecies that could be detected in all of the extracts of samples. Arsenosugar PO4 was the majorcompound in most samples (0.3-13.9mg/kg of dry weight), followed by arsenosugar OH (0.7-6.2mg/kg of dry weight). A further experiment was done to investigate the stability of arsenosugars inthe process of being heated. It was observed that the arsenosugars were stable during a short-termheating at 100℃. Their stability in human ingestion was also studied. A substantial increase ofdimethylarsinic acid (DMA) was detected in urine samples collected from six volunteers after theconsumption of this seaweed. The results obtained indicated that arsenosugars had been metabolizedto DMA, which is more toxic than arsenosugars. From this point of view, consumers should considerthe possible adverse effects of edible Porphyra on human health and choose those Porphyra havinglower arsenic concentrations.