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ARS Home » Midwest Area » West Lafayette, Indiana » National Soil Erosion Research Laboratory » Research » Publications at this Location » Publication #185561
Title: IMPROVEMENT OF METALS AND PHOSPHORUS ANALYSIS IN WATER SAMPLES BY ICP-OES RF POWER AND NEBULIZER GAS FLOW RATE MODIFICATION

Author
item DECAMPOS, A - PURDUE UNIVERSITY
item ROCHA, C - UNIV. CATOLICA DE GOIAS
item Smith, Douglas
item Huang, Chi Hua

Submitted to: Communications in Soil Science and Plant Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/30/2006
Publication Date: 7/1/2007
Citation: Decampos, A.B., Rocha, C., Smith, D.R., Huang, C. 2007. Improvement of metals and phosphorus analysis in water samples by ICP-OES RF power and nebulizer gas flow rate modification. Communications in Soil Science and Plant Analysis. 38:1179-1191.

Interpretive Summary: Inductively coupled plasma atomic emission spectrometry is a powerful tool for simultaneous analysis of many different elements. The optimization of its operational parameters is important for achieving best performance. This study was conducted with the objective of determining optimum radio frequency forward power and nebulizer gas flow parameters for Al, Cu, Fe, Mn, Na, P, and Zn in natural water samples. Five radio frequency powers (800, 950, 1110, 1300, and 1400 W) and four nebulizer gas flow rates (0.75, 1.00, 1.25, and 1.50 L min-1) were tested at standard analyte concentrations of 1 and 10 mg L-1. Different radio frequency powers values and nebulizer gas flow rates were found to be ideal for each element. For instance, Al, Na, and P showed best performance at the highest radio frequency power, whereas Cu and Zn performed better at lower radio frequency powers. Nebulizer gas flow rates of 1 L min-1 was chosen for Na, Fe, Zn, and Al, and 0.75 L min-1 for Mn and Cu. Grouping the elements with similar parameters may be an option to avoid reading delays. The impact of this study is to guide future research efforts in the analysis of these elements using inductively coupled plasma atomic emission spectrometry.

Technical Abstract: Inductively coupled plasma atomic emission spectrometry (ICP-OES) is a powerful tool for simultaneous multielement analysis. The objective of this study was to determine optimum ICP-OES radio frequency forward power (RF power) and nebulizer gas flow parameters for Al, Cu, Fe, Mn, Na, P, and Zn in natural water samples. Five RF powers (800, 950, 1110, 1300, and 1400 W) and four nebulizer gas flow rates (0.75, 1.00, 1.25, and 1.50 L min-1) were tested at standard analyte concentrations of 1 and 10 mg L-1 and at fixed values of auxiliary, plasma, sample flow rate, and element wavelengths. Different RF powers values and nebulizer gas flow rates were found to be ideal for each element. For instance, Al, Na, and P showed best performance at RF power set at 1400 W whereas Cu and Zn at 1250 and 950 W, respectively; the nebulizer gas flow rates of 1 L min-1 was chosen for Na, Fe, Zn, and Al, and 0.75 L min-1 for Mn and Cu. The differences in RF power and nebulizer gas flow rates were found to be driven by changes in 1) element emission lines for different RF powers; 2) evaporation rates, mean diameter drop sizes, solvent loading and analyte signal intensities for different nebulizer gas flow rates and analyte concentrations. Grouping the elements with similar parameters may be an option to avoid reading delays. The impact of this research is to guide the analysis of samples for these elements using ICP-OES.