Assessment of rare earth elements by ICP-MS in workplace air of metallurgical enterprise

Abstract

The authors specified a new method to assess 15 rare earth elements in one workplace air sample by mass spectrometry with inductively coupled plasma. The article contains conditions of workplace air sampling and settings of mass spectrometer Agilent 7500сх (USA) for quantitative assessment of 15 rare earth elements in wide range of concentrations. The authors selected concentrations to build calibration curves, justified a choice and use of internal standard for consideration of matrix effect, transport disturbances and more precise analysis. Experiments helped to evaluate necessary optimal volume of air sample and allowable speed of sampling, to justify choice of aerosol filters, to study matrix influence on analysis accuracy by «input-found» method, to set conditions of preparing aerosol filters of AFA-HA, AFA-HP types with use of microwave system, muffle furnace and acid dissolution in thermal chamber. High sensitivity of the specified method measuring mass concentrations of 15 elements in workplace air, when sampling 0,1 m3of air by ICP-MS method with use of reaction collisional cell with helium, enables to detect lanthanum in range of 0,001–25 mg/m3, cerium — 0,001–10 mg/m3, praseodymium — 0,0005–10 mg/m3, neodymium — 0,001–100 mg/m3, samarium — 0,0005–100 mg/m3, europium — 0,001–50 mg/m3with 21% error; yttrium — 0,0005–25 mg/m3, gadolinium — 0,0001–100 mg/m3, terbium — 0,0001–10 mg/m3, dysprosium, holmium, erbium — 0,0005–50 mg/m3, thulium — 0,0005–10 mg/m3, ytterbium — 0,0005–100 mg/m3, lutetium — 0,0001–25 mg/m3with 20–21% error.Content of rare earth elements in workplace air of metallurgic enterprise at workplaces, mg/m3: lanthanum 0,003–0,0019, cerium 0,00065–0,0036, praseodymium 0,00006–0,00034, neodymium 0,00002–0,0009, samarium 0,00001–0,00 006, europium 0,000008–0,00001, yttrium under 0,00001, gadolinium 0,00002–0,000034, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium under 0,000007.