Aerosol dilution as a new sample introduction strategy for microwave-induced plasma optical emission spectrometry.

A new sample introduction method using aerosol dilution for microwave-induced plasma optical emission spectrometry (MIP OES) is presented. Signal emissions from N2+ and OH species were monitored for plasma diagnostics and quantity of solvent plasma load (QSPL). The N2+/OH signal intensity ratio demonstrated that aerosol dilution is a desolvation process which can reduce the QSPL, increasing plasma energy. Efficiency of the system was observed with solutions containing the easily ionizable element (EIE) Na, without important alteration of the plasma physics at concentrations up to 5 g L-1. Atomic and ionic lines of Cr, Mn, V and Zn in saline solutions proved to have distinct variations. Despite the lower amount of analyte introduced, the LOQs of these elements were similar to the ones obtained from conventional nebulization. The analysis of two CRMs (fertilizer, NIST 695 and tomato leaves, NIST 1573a) resulted in percentage recoveries within 90-130%. Aerosol dilution in MIP OES (AD-MIP OES) brings increased robustness to the technique, once complex matrices can be introduced with the advantage of suppressing matrix interferences. Additionally, the sample is less prone to dilution error, and costs are saved due to increased life span of consumables since less sample matrix is introduced in the plasma.

Aerosol dilution as a simple strategy for analysis of complex samples by ICP-MS.

This study investigated the capability of High Matrix Introduction (HMI) strategy for analysis of dialysis solution and urine samples using inductively coupled plasma mass spectrometry. The use of HMI enables the direct introduction of urine samples and dialysis solutions 2-fold diluted with 0.14molL-1 HNO3. Bismuth, Ge, Ir, Li, Pt, Rh, Sc and Tl were evaluated as internal standards for Al, Ag, As, Be, Cd, Cr, Pb, Sb, Se, Tl, and Hg determination in dialysis solution and As, Cd, Hg and Pb determination in urine samples. Helium collision cell mode (4.5mLmin-1) was efficient to overcome polyatomic interferences in As, Se and Cr determinations. Mercury memory effects were evaluated by washing with 0.12molL-1 HCl or an alkaline diluent solution prepared with n-butanol, NH4OH, EDTA, and Triton X-100. This later solution was efficient for avoiding Hg memory effects in 6h of analysis. Linear calibration curves were obtained for all analytes and detection limits were lower than maximum amounts allowed by Brazilian legislations. Recoveries for all analytes in dialysis solutions and urine samples ranged from 82% to 125% and relative standard deviations for all elements and samples were lower than 7%. Analysis of control internal urine samples was in agreement with certified values at 95% confidence level (t-test; p < 0.05).