Elemental Scientific seafast S2 seafast S2 TM Authors: Nathan Saetveit (nathan@icpms.com) Brief The seafast S2 is an automated sample introduction system for multi-mode determination of ultra-trace metals in undiluted seawater. It lowers procedural blanks and improves detection limits for a variety of elements through syringe-based sample preconcentration and matrix elimination. Features: Fully automated, inline preconcentration and matrix removal Direct mode with up to 50x dilution Offline preconcentration mode (optional) Syringe-driven reagents for consistent chemistry and maximum throughput and cleanliness Higher preconcentration factors Flexible sample preconcentration volume Automatic cleaning of buffer cleanup column Completely enclosed liquid flow path for ultra-low blanks Elution Profiles Automated ICPMS optimization Elemental Scientific Figure 1. Simultaneous elution of 6 elements in Preconcentration mode at 1 ppb. 1
SC DX DIWater Buffer Diluent Carrier Figure 2. seafast S2 system with integrated mobile stand. Abstract The seafast S2 is a high performance, automated sample introduction system for the determination of trace elements in seawater and other high matrix samples by ICPMS. Undiluted samples can be measured directly with a user-specified dilution while simultaneously loading an aliquot of sample onto a column for automated, online preconcentration and matrix removal. Both Direct and Preconcentration modes reduce procedural blanks associated with offline sample preparation, and Preconcentration mode dramatically improves detection limits by eliminating matrix effects and increasing sensitivity. The seafast S2 offers complete flexibility and can run in Direct, Preconcentration, or both modes by simply selecting the desired mode(s) in the ESI software. seafast Preconcentration Column 2
seafast S2 Preconcentration or Direct Mode Direct mode Figure 3. Periodic table showing the possible modes for each element. Modes Preconcentration mode: A chelation column binds transition metals and rare earth elements but allows matrix,, Ca 2+ and Mg 2+ ions to be rinsed out. After the preconcentration step, analytes are eluted and detected by ICPMS. Direct mode: Sample is automatically diluted inline by high-precision syringe pumps. Dilution reduces matrix effects and allows the determination of elements whose chemistry is not compatible with the preconcentration column. 3
Preconcentration Mode seafast Preconcentration - Seawater Loading (ph ~ 6) 2) Column rinse (ph ~ 6) 3) Elution (ph < Mg 2+ M+ Ca 2+ Mg 2+ Mg 2+ Ca 2+ M+ M+ Mg 2+ Ca 2+ Cl H - 2 O Ca 2+ Figure 4. At a ph ~ 6, many metals are chelated on the preconcentration column, while matrix elements are flushed from the column. Metals are eluted directly to the ICPMS with nitric acid. Detection Limits in DRC and KED, Preconcentration Mode 10 LOG IDL (ppt) 1 0.1 0.01 V Mn Fe Co Ni Cu Zn Cd Pb DRC IDL KED IDL Figure 5. Detection limits are near or better than 1 ppt on a quadrupole ICPMS (n=10, 3σ). 4
Ultratrace Calibration R 2 = 0.999996 R 2 = 0.999968 Figure 6. Preconcentration mode calibration of Fe and Zn in 3.5% NaCl. Calibration spikes are 1, 10, 50 and 250 ppt. 5
Washout Factors: Co, Cu, Zn, Cd, and Pb 10000 1000 LOG Concentra-on (ppt) 100 10 1 >4,000x >25,000x 1ppt 0.1 >100,000x >270,000x 0.01 5000 ppt Blank1 Blank2 1% Nitric Acid Standards 1% Nitric acid + 3.5% Ultrapure NaCl Standards Direct Mode Figure 7. Washout in Preconcentration mode is excellent with both 1% nitric acid calibration standards and matrix-matched standards. Matrix matching the standards with seablank is not required for Preconcentration mode, but it enhances washout. Inline Dilution R 2 = 0.999996 Figure 8. Direct mode calibration of Tl in 3.5% NaCl. Calibration spikes are 1, 10, 50, 250 and 500 ppt. 6
Results seafast S2 NASS-6 Determination, DRC, Preconcentration and Direct P = Preconcentration Mode D = Direct Mode seafast S2 CASS-5 Determination, DRC, Preconcentration and Direct 10000 1000 LOG Concentra-on (ppt) 100 10 1 0.1 0.01 V (P) Cr (D) Mn (P) Fe (P) Co (P) Ni (P) Cu (P) Zn (P) Mo (D) Cd (P) Pb (P) U (P) IDL CASS- 5 (n=4) Cer-fied Value Figure 9. Results for NASS-6 and CASS-5 Seawater Reference Materials are shown. Elements determined with the seafast S2 are accurate and precise for elements with certified concentrations from < 10 ppt to > 10 ppb. 7
Benefits: Low blanks Low carryover Sub-ppt IDL's FAST: < 8 minutes inline Eliminate pump tubing No daily maintenance Easy ICPMS optimization 1500 North 24th Street Omaha, NE 68110 USA Phone: 1.402.991.7800 Fax: 1.402.991.7799 Email: prepfast@icpms.com Web: www.prepfast.com www.icpms.com Elemental Scientific 8