To evaluate the feasibility of urine perchlorate as a biomarker of ammonium perchlorate (AP) exposure and to explore the correlation between the thyroid function indicators and the perchlorate concentrations, a sensitive and selective ultra-high-performance liquid chromatography-mass spectrometry (UHPLC-MS) method was developed to detect perchlorate in urine samples. Rats were orally administrated with different doses of perchlorate. Serum free thyroxine (FT4), free triiodothyronine (FT3), and thyroid-stimulating hormone (TSH) were determined by radioimmunoassays. The results showed that a dose of AP up to 520 mg kg(-1) body weight induced a significant increase of TSH, with a decrease of FT4. Particularly, the levels of urine perchlorate increased dose-dependently on AP exposure from drinking water. The findings highlighted that urine perchlorate may be a useful biomarker for AP environmental exposure.

It is important to find the proper levitated positions in the standing wave levitator. Using ANSYS and MATLAB, the standing wave field and the time average potential are simulated with the levitator whose radiating surface and reflecting surface are concave spheres. The simulation results show that the position close to reflecting surface deviates from the central axis, the others in the central axis. Levitation experiments for the light specimens are carried out with the standing wave levitator, which conforms to the simulation results.