Direct determination of lead in biological samples by electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS) after furnace-fusion in the sample cuvette-tungsten boat furnace

摘要

The newly conceived electrothermal vaporiza-tion (ETV) system using a tungsten boat furnace (TBF) sample cuvette was designed for the direct analysis of solid samples with detection by inductively coupled plasma mass spectrometry (ICP-MS). Into this small sample cu-vette, a solid mixture of the biological samples and di-ammonium hydrogenphosphate powder as a fusion flux was placed and situated on a TBF. Tetramethylammoniuni hydroxide solution was added to the mixture. After the on-furnace digestion had been completed, the analyte in the cuvette was vaporized and introduced into the ICP mass spectrometer. The solid samples were analyzed by using a calibration curve prepared from the aqueous standard so-lutions. The detection limit was estimated to be 5.1 pg of lead, which corresponds to 10.2 ng g’ of lead in solid samples when a prepared sample amount of 1.0 mg was applied. The relative standard deviation for 8 replicate measurements obtained with 100 pg of lead was calcu-lated to be 6.5%. The analytical results for various biolog-ical samples are described.