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.

The novel coupling method based on the hyphenation of immunoreaction with ICP-MS was developed andapplied to the determination of thyroid-stimulating hormone (TSH) in human serum. In this system, TSH wasfirstly captured by anti-TSH monoclonal antibodies immobilized on a solid support. Biotinylated anti-TSHmonoclonal antibodies and Eu3z-labell3+-ed streptavidin were then added to form the complex, capturedantibody-TSH-biotinylated anti-TSH antibody-Eu3z-labelled streptavidin. After unbound reactants werewashed away, Eu3z bound to the complex was extracted by 1% HNO3 and measured by ICP-MS. The Eusignal was directly proportional to the serum TSH concentration. The limit of detection was 0.5 mIU L-1 andthe assay was linear up to 170mIU L-1. The within-run (n=6) and between-run (n=6) relative standarddeviations (RSD) for low, medium and high concentration standards did not exceed 10%. The TSH resultsobtained by this procedure correlated well with those obtained by radioimmunoassay (r2=0.9639).

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.

This paper describes a novel aerosol chemiluminescencebaseddetector, which can be coupled to liquid chromatographyfor the determination of the chemicals with weakoptical absorbance in the UV-visible region. This aerosolchemiluminescence (CL)-based detector, in which HPLCeffluent is converted to aerosol and then generated CLemission on the surface of porous alumina, is composedof three main processes: nebuliztion of HPLC effluent, CL emission on surface of porous alumina material, andoptical detection. To demonstrate the utility of the aerosolchemiluminescence detector, some compounds such saccharides, poly (ethylene glycol)s, amino acids, and steroidpharmaceuticals are determined by the present aerosolchemiluminescence detection method. Compared with anevaporative light scattering detector, the proposed detectorshows the following features: (a) extensive CL emissionson porous alumina by many compounds tested, which leads to the potential application for the determinationof volatile and nonvolatile chemicals with or withoutUV-visible absorbance; (b) a CL mechanism based on thecatalytic oxidation of analytes, not on the light scattering,which suggests the present detector be free from theinterference of the inorganic and nonvolatile mobile-phasemodifiers. The CL characteristics and effect of differentparameters, such as temperature and nebulizer gas flowrate, were also discussed in this paper. Furthermore, thisaerosol chemiluminescence-based detector was successfullyapplied to the determination of raffinose, glucose,sucrose, maltose, and r-lactose.