Author FIELD APPLICATION REPORT ICP-Mass Spectrometry and ICP-Optical Emission Spectroscopy Determination of Micro and Macro Elements in Waters with the ELAN DRC-e Riccardo Magarini PerkinElmer Italia S.P.A. via Tiepolo 24 20052 Monza, Italy Table 1. ELAN DRC-e Instrumental Parameters. Table 2. Reaction Cell Parameters. Nebulizer Meinhard, Type C (glass) Sample Uptake Rate 1 mL/min Isotope Spray Chamber Peltier-cooled cyclonic at 2 °C Injector Alumina, 2 mm Plasma Power Cones Dwell Time Sweeps/Reading 1-1.5 sec Replicates 4 0.25 Standard Na --- --- 0.015 0.25 EDR* Mg --- --- 0.012 0.25 EDR* K --- --- 0.0135 0.25 EDR* Ca --- --- 0.010 0.25 EDR* O 2 0.80 0.000 0.70 DRC 55 59 60 43 20-50 Cr, Se, 52 Mode 0.000 54 39 25-50 ms RPq --- 27 26 Ni RPa B, Al, Fe, Mn, Co, Ni, 65Cu, 111Cd, 137Ba, 208Pb --- 11 23 1400 W Integration Time Reaction Gas Flow Gas (mL/min) 77 AsO 91 * = Extended Dynamic Range Table 3. Optima 5300 DV Instrumental Parameters. Introduction The ability of reaction cell technology to reduce the effects of spectral interferences is well-known, but another, lesser-known capability also exists: extending the dynamic range. This is accomplished by adjusting the bandpass parameters with no gas in the cell. Because the bandpass parameters can be adjusted on a per-mass basis, sensitivity can be reduced on selected isotopes without affecting other elements in the method. This advantage is seen when analyzing samples for both trace and high-level elements, as shown previously.1 This work demonstrates the ability of the ELAN® DRC™-e to analyze drinking and saline waters for both major and minor elements in a single run. Experimental Reagents and Sample Preparation Samples were analyzed without any pre-treatment. Drinking waters were analyzed directly, while saline waters were diluted 12.5 times with 1% (v/v) HNO3 (Suprapur®, Merck®). Internal standards were used to compensate for possible matrix effects during sample introduction. An internal standard mix (Y, Rh and Re) was added on-line by using orange/green peristaltic pump tubing and an internal standard addition kit. 2 Nebulizer MiraMist, 0.55 Lpm Sample Uptake Rate 1.3 mL/min Spray Chamber Glass Cyclonic Injector Alumina, 2 mm Plasma Power 1400 W Integration Time 5-20 sec Replicates 3 External calibration curves were applied using standards ranging from 5 µg/L to 400 mg/L, depending on the element and expected levels. For example, elements likely to be present at low concentrations (i.e. As, Se, Pb) used calibration curves established with 5, 10, 50, and 100 µg/L standards, while high-level elements (i.e. Na, Mg, K, Ca) used standards at mg/L concentrations. Instrumentation All analyses were performed on an ELAN DRC-e ICP-MS equipped with Peltier cooled spray chamber and a Meinhard® C-type glass concentric nebulizer. In the method, the elements were grouped into 3 modes: standard mode, extended dynamic range mode (i.e. standard mode with the application of bandpass parameters), and DRC mode using oxygen as a reaction gas. Instrumental parameters are reported in Table 1, while DRC cell conditions appear in Table 2. The samples were also analyzed for comparison by ICP-OES, using an Optima™ 5300 DV. Taking advantage of the Optima 5300 DV flexibility, macro elements were determined radially and micro elements axially. Several wavelengths were used for each element to check for possible spectral interferences; the preferred wavelengths, along with analysis mode and instrumental conditions, are reported in Tables 3 and 4. Table 4. Wavelengths and Analysis Mode. Table 5. DRC-ICP-MS and ICP-OES Results for Drinking Waters. Element Wavelength (nm) Mode B 249.677 Radial Sample 1 Element ICP-MS ICP-OES Customer* ICP-MS Na 589.592 Radial Mg 285.213 Radial Al 394.401 Radial K 766.490 Radial Ca 315.887 Radial Cr 205.560 Axial Fe 238.204 Radial Mn 257.610 Radial Co 228.616 Axial Ni 231.604 Axial Cu 327.393 Axial Cu-65 1.47 1.1 0.0 1.97 2.6 2.0 µg/L As 188.979 Axial AsO-91 0.09 1.3 0.0 0.51 1.0 0.5 µg/L Se 196.026 Axial Se-77 0.74 1.4 0.0 0.09 <1 0.2 µg/L Cd 228.802 Axial Cd-111 0.012 <0.1 0.0 0.05 <0.1 0.05 µg/L Ba 233.527 Axial Ba-137 26.2 22.1 21.0 2.24 2.04 2.0 µg/L Pb 220.353 Axial Pb-208 3.65 8.4 5.6 0.51 2.0 0.5 µg/L Sample 2 ICP-OES Customer* Units B-11 0.48 0.56 n.a. 0.02 0.02 0.01 mg/L Na-23 420 445 490 193 180 200 mg/L Mg-26 88.5 90.0 n.a. 0.08 0.09 n.a. mg/L Al-27 0.003 0.007 0.000 0.003 0.007 0.001 mg/L K-39 13.9 15.1 13.0 9.17 9.61 10.0 mg/L Ca-43 151 147 168 0.16 0.17 n.a. mg/L Cr-52 0.54 1.4 0.0 0.71 0.8 0.5 µg/L Fe-54 0.07 0.08 0.09 0.006 0.005 0.002 mg/L Mn-55 0.006 0.010 0.000 0.001 0.002 0.001 mg/L Co-59 0.15 0.3 n.a. 0.01 <0.2 n.a. µg/L Ni-60 1.13 1.0 2.1 2.12 2.1 2.0 µg/L * = GF-AAS; HG-AAS; ICP-OES Results Figure 1 shows calibration curves for Na, Mg, K, and Ca, which demonstrates linearity up to 400, 100, 40, and 200 mg/L levels, respectively. Higher level standards were not analyzed. The ability to extend the linearity is the result of the capability to selectively suppress the analyte signal using one of the bandpass parameters. The extent of signal suppression can be controlled by varying the RPa value. Tables 5 and 6 show both the ICP-MS and ICP-OES results for drinking waters and saline waters, respectively, along with results supplied by the customer, which were generated by using graphite furnace AAS, hydride generation AAS, and ICP-OES. There is good agreement between all techniques for elements present at both trace and elevated levels, which confirms the concentrations. The effectiveness of extending the dynamic range is evidenced by the results for Na and Mg in the saline waters: the concentrations from both ICP-MS and ICP-OES are nearly identical. 3 Figure 1. Calibration curves for Na, Mg, K, and Ca demonstrating extended dynamic range. 4 Conclusion Table 6. DRC-ICP-MS and ICP-OES Results for Saline Waters. Sample 1 Element ICP-MS ICP-OES Customer* ICP-MS Sample 2 ICP-OES Customer* Units B-11 0.11 4.54 5.06 2.30 0.10 n.a. mg/L Na-23 10950 10608 11000 108 103 103 mg/L Mg-26 1283 1308 1300 146 149 146 mg/L Al-27 0.08 0.10 0.005 10.9 10.4 10.0 mg/L K-39 409 398 390 7.36 6.70 5.80 mg/L Ca-43 440 410 448 158 163 200 mg/L Cr-52 9.95 7.5 2.5 1.69 1.8 0.0 µg/L Fe-54 0.11 0.15 0.09 8.02 7.88 8.00 mg/L Mn-55 0.07 0.08 0.07 8.84 8.43 8.60 mg/L Co-59 1.04 0.8 n.a. 88.9 109 n.a. µg/L Ni-60 17.8 13.1 10.0 169 194 110 µg/L Cu-65 15.8 13.6 10.0 5.50 4.2 0.0 µg/L AsO-91 10.4 4.8 10.2 0.15 1.8 n.a µg/L Se-77 3.29 12.0 1.0 <0.02 <1 0.0 µg/L Cd-111 0.32 0.3 0.25 0.55 0.6 0.0 µg/L Ba-137 53.2 42.5 37.0 56.4 51.5 51.0 µg/L Pb-208 4.07 12.9 2.5 0.62 9.5 0.0 µg/L * = GF-AAS; HG-AAS; ICP-OES This work has demonstrated the ability of DRC-ICP-MS to analyze elements present at both trace and elevated levels in drinking and saline water samples. The capability to selectively suppress signal intensity without the use of a cell gas allows the dynamic range of DRCICP-MS to be extended, which allows for matrix elements to be measured. All results were confirmed using ICP-OES. Although both ICP-OES and DRC-ICP-MS give similar results for these samples, it should be remembered that these are complementary techniques, with each having their strengths and weaknesses for various sample types and analyte levels. References 1. F. Abou-Shakra, “Extending the Dynamic Range of the ELAN DRC by Selective Attenuation of High Signals”, PerkinElmer FAR 007437_01, 2005. Table 7. Calibration report. Analyte Mass Curve Type Slope Intercept Corr Coeff B 10.013 Linear Thru Zero 0.036264 0.000 0.998990 B 11.009 Linear Thru Zero 0.161083 0.000 0.999266 Na 22.990 Linear Thru Zero 0.034193 0.000 0.999943 Mg 25.983 Linear Thru Zero 0.062046 0.000 0.999956 Al 26.982 Linear Thru Zero 1.176079 0.000 0.999969 K 38.964 Linear Thru Zero 0.246574 0.000 0.999961 Ca 42.959 Linear Thru Zero 0.003598 0.000 0.999927 Fe 53.940 Linear Thru Zero 0.114004 0.000 0.999870 Mn 54.938 Linear Thru Zero 1.106387 0.000 0.999844 Y 88.905 Linear Thru Zero 0.000000 0.000 0.000000 Rh 102.905 Linear Thru Zero 0.000000 0.000 0.000000 PerkinElmer, Inc. 940 Winter Street Waltham, MA 02451 USA P: (800) 762-4000 or (+1) 203-925-4602 www.perkinelmer.com For a complete listing of our global offices, visit www.perkinelmer.com/ContactUs Copyright ©2006-2009, PerkinElmer, Inc. All rights reserved. PerkinElmer® is a registered trademark of PerkinElmer, Inc. All other trademarks are the property of their respective owners. The data presented in this Field Application Report are not guaranteed. Actual performance and results are dependent upon the exact methodology used and laboratory conditions. This data should only be used to demonstrate the applicability of an instrument for a particular analysis and is not intended to serve as a guarantee of performance. 008584_01