Using the Aridus 3 Desolvating Nebulizer System in Geochemistry - - PowerPoint PPT Presentation

Using the Aridus 3 Desolvating Nebulizer System in Geochemistry

Liquid Sample Introduction

Desolvating Pneumatic Nebulizer System

• Combine a low-flow inert pneumatic nebulizer with a

heated PFA spray chamber and fluoropolymer membrane desolvator for liquid sample introduction to an ICP-MS instrument.

Liquid Sample Introduction

Desolvating Pneumatic Nebulizer System

• Benefits

– Introduction of corrosive liquid samples that may contain hydrofluoric acid (no silicon-containing wetted parts) – Introduction of low volume (< 1mL volume) liquid samples – Analyte ICP-MS signal enhancement – Reduction of solvent-based mass spectral interferences (ex. hydrides, oxides)

Desolvating Pneumatic Nebulizer System

Applications

• Geochemistry

– U-series dating studies (geochronology) – Ca, Fe, Hf, Mg, Nd, Ni, Pb, S, Si, Sr isotope measurements

• Semiconductor

– High-purity acids (ex. HNO3, HCl) and solvents (ex. isopropanol)

• Pharmaceutical

– Samples dissolved in DMF (dimethylformamide)

• Clinical

– U and Pu in urine

Aridus3 Desolvating Nebulizer System Front View

Dimensions: 33.7 cm W x 19.2 cm H x 52.0 cm D

Teledyne CETAC Aridus3 Schematic

Gas Flow Outline

Aridus3 Desolvating Nebulizer System Block Diagram

Desolvating Pneumatic Nebulizer System

Operational Characteristics

• Heated PFA Spray Chamber and Heated Membrane

Desolvator

– Maintain nebulized liquid sample in vapor phase

• Argon Sweep Gas Flow

– Establish humidity gradient across membrane to remove sample solvent vapor

• Nitrogen Addition Gas

– Introduced after membrane desolvator; low-flow N2 addition to the dry sample gas stream may enable better energy coupling between the induction region of the ICP-MS plasma and the central channel of the plasma.

Desolvating Pneumatic Nebulizer System

Operational Characteristics

• Argon Sweep Gas Supply

– May be from a separate Ar source or teed from main Ar supply for the host ICP-MS

• Nitrogen Addition Gas Supply

– N2 source (ex. compressed cylinder) should be 99.995% or better

Desolvating Pneumatic Nebulizer System

Operational Characteristics

• Nitrogen Addition Gas

– Can cause mass spectral interferences

• Examples: 40Ar14N+ on 54Fe+and 54Cr+, 40Ar14N2

+ on 68Zn+

– N2 gas flow can be reduced or replaced with low flow of Ar

Desolvating Pneumatic Nebulizer System Reference for N2 Addition

• 1. G.L Scheffler and D. Pozebon, Advantages,

drawbacks, and applications of mixed Ar-N2 sources in inductively coupled plasma – based techniques: an overview, Anal. Methods, 2014, 6, 6170-6182.

Aridus3 Desolvating Nebulizer System CFlow PFA Nebulizers

Encapsulated carbon-fiber support Neb gas supply port for 4mm tubing

Uptake rates (self-aspiration) of 50,100 or 200 microliters/min

Aridus3 Desolvating Nebulizer System

CFlow Nebulizer w. PFA Spray Chamber

Port accepts standard 6mm diameter nebulizers

Spray Chamber Drain Line

Aridus3 Desolvating Nebulizer System

Connections for Power, Communications, Gas Flows, Sample Out, Ar Sweep Gas Out

Aridus3 Desolvating Nebulizer System

• w. Nu Instruments MC-ICP-MS

Aridus3 AridusII

Aridus3 Desolvating Nebulizer System

• w. ThermoFisher Neptune MC-ICP-MS

Aridus3 Desolvating Nebulizer System

4-Liter Trap Bottle (Ar Sweep Gas Out)

Vent Out Line 4-Liter Trap Bottle Insulated Sweep Gas Out Line

Aridus3 Desolvating Nebulizer System AridusLink Software

Desolvating Pneumatic Nebulizer System

Suggested Tuning Steps (1) – Aridus3 w. ICP-MS

1. Set the Ar sweep gas flow to 1.00 L/min and the N2 addition gas flow to 0.5 mL/min or less before starting the ICP-MS plasma. 2. Start the ICP-MS plasma and set the PFA nebulizer gas flow to 1.00 L/min. 3. Introduce a tuning solution (ex. 1ppb) containing elements such as Co, Y, In, Ce, Pb, U to the PFA nebulizer. 4. Increase the Ar sweep gas flow until the Ce signal stops increasing and the % CeO/Ce begins to go over 1.0% A typical range may be 3.00 to 6.00 L/min Ar. 5. Introduce the N2 addition gas; a typical flow range may be 3.0 mL/min to 6. 10.0 mL/min. Add the N2 until the tune element(s) signal begins to level

• ff or significantly decreases.

Desolvating Pneumatic Nebulizer System

Suggested Tuning Steps (2) – Aridus3 w. ICP-MS

6. Adjust the Ar sweep gas flow (usually downward) until the %CeO/Ce ratio is ~0.1% or less. Often the analyte signal (ex. In, Ce) will increase after the Ar sweep gas is adjusted. 7. Adjust the PFA nebulizer gas flow for highest signal and lowest %CeO/Ce.

• 8. Optimize the ICP-MS torch xyz sampling position for the highest analyte

signal.

• 9. Optimize the ICP-MS ion optics for the highest analyte signal.
• 10. The Ar sweep gas and N2 addition gas may be fine tuned for

best signal and lowest oxides; the %CeO/Ce will typically be 0.05%

• r less.

Aridus3 Desolvating Nebulizer System

Tune Signal Profile w. MC-ICP-MS

235U signal in red. Variable Ar sweep gas flows (L/min);

N2 set at 3.9 mL/min

3.00 3.50 4.00 4.25 4.50

Tuning profile during introduction of enriched solution of

235U at concentration of 0.11 picomole/mL. Maximum 235U signal is ~ 250,000 cps or ~ 5.0 mV.

Aridus3 Desolvating Nebulizer System

Tune Signal Profile (1) w. Quad ICP-MS

1ppb In and Ce; 1.0s int. time

Vary Ar Sweep Gas flow (L/min) Neb gas set at 1.0 L/min N2 set at 0.5 mL/min

1.00 1.50 2.00 2.50 3.00 3.50

Aridus3 Desolvating Nebulizer System

Tune Signal Profile (2) with Quad ICP-MS

1ppb In and Ce; 1.0s int. time 3.00 3.50 Add 6.0 mL/min N2 3.25 3.00 2.90 2.80 Set neb gas at 0.90 L/min

Aridus3 Desolvating Nebulizer System

Tune Signal Profile (3) w. Quad ICP-MS

1ppb In and Ce; 1.0s int. time Full tune of xyz torch position & ion optics Neb Gas 0.90 L/min Ar Sweep Gas 2.80 L/min N2 gas 6.0 mL/min

Sample Preparation - Geology

Outline for Speleothems and U-Series Dating

• Sample powder masses generally from 20 to 100 mg
• Sample powders dissolved in 15N HNO3 and spiked with

a mixed 229Th-233U-236U solution.

• Subsamples dried and re-dissolved in 7N HNO3
• Subsamples added to anionic resin columns to separate

the U and Th

• Spiked aliquots of U and Th in 3% HNO3 are then

analyzed using MC-ICP-MS Speleothems: cave deposits U-Series Dating: based on ratio of 234U to 230Th in a sample, with the 230Th a decay product of 234U

Sample Preparation - Geology

Reference

Cheng, H., Edwards, R.L., Shen, C.-C., Polyak, V.J., Asmerom, Y., Woodhead J., Hellstrom, J., Wang, Y., Kong, X., and Spötl, C., Improvements in 230Th dating, 230Th and 234U half-life values, and U-Th isotopic measurements by multi-collector inductively coupled plasma mass spectrometry, Earth and Planetary Science Letters, v. 371, p.82-91, 2013.

Sample Types

Stalagmite

Sample BC9-88mm was drilled to screen this sample for its age. 8 cycles were run per block with an integration time of 20 seconds per cycle.

Stalagmite BC9, Carlsbad Cavern, New Mexico USA Sample collected by V. Polyak by federal permit granted by Carlsbad Cavern National Park.

9 cm

Sample Types

Stalagmite BC9 Carlsbad Cavern, New Mexico USA

130 mg calcite powder

238U = 0.5205 ± 0.0005 ppm 232Th = 0.00320 ± 0.00004 ppm 230Th/232Th = 18.6 ± 0.3 230Th/238U = 0.0374 ± 0.0003

δ234Umeasured = 1554 ± 3 ‰ δ234Uinitial = 1561 ± 3 ‰ Age uncorrected = 1608 ± 14 yr B2k Age corrected = 1210 ± 120 yr B2k δ = activity ratio Yr BP = years before 2000CE

Sample Types

Moonmilk – Grand Canyon, Arizona USA

Moonmilk is a cave deposit (speleothem) that has a toothpaste-like consistency. Mineral is calcite.

Sample Types

Moonmilk – Grand Canyon, Arizona USA

sample powder size = 50 mg

238U concentration (ppm) = 0.6610 ± 0.0005 232Th concentration (ppb) = 11.24 ± 0.05 230Th/ 232Th activity = 4.0 ± 0.1 230Th/ 238U activity = 0.02209 ± 0.00083

δ234U measured = 297 ± 1 ‰ δ234U initial = 299 ± 1 ‰ uncorrected age = 1871 ± 71 yr BP corrected age = 1492 ± 202 yr BP

Sample Types

Altered Stalagmite Hidden Cave, Guadalupe Mountains, NM USA

Testing age of altered layers, age corrected 22,959 +/- 1498 BP

50 mm

Sample Types

Old Stalagmite (cross-section) Fort Stanton Cave, Central NM USA

100 mm

stalactite straw 443,587 ± 10,204 BP Age corrected

Aridus3 Desolvating Pneumatic Nebulizer System in Geochemistry

Using the Aridus3 with a CFlow-100 PFA nebulizer enhances analyte signal by a factor of 4 to 5 making analyses easier and

• faster. Smaller masses of often limited (and expensive to obtain)

samples can be analyzed, which can also reduce sample column chemistry time.

Note that the Neptune MC-ICP-MS was equipped with Jet sample and X interface skimmer cones but not with the high performance interface vacuum pump.

Acknowledgement

• We would like to thank Dr. Yemane Asmerom and Dr.

Victor Polyak of the University of New Mexico Department of Earth and Planetary Sciences for their assistance with tests of the Teledyne CETAC Aridus3 unit with the Thermo Neptune MC-ICP-MS.

Automated Sample Introduction with the Aridus3

ASX-112FR Autosampler

Automated Sample Introduction

ASX-112FR Autosampler Sample Tray

24 position central rack 1.5 mL PFA vials

Automated Sample Introduction

ASX-112FR Autosampler Sample Racks

30 position, 14 mL PP vials 42 position, 7 mL PP vials

Automated Sample Introduction

ASX-112FR Autosampler QuickWash3 Accessory

Where to go for more information

• Service support

– cetacservice@teledyne.com

• Sales support

– cetacsales@teledyne.com

• Technical support

– Fred.Smith@Teledyne.com – Paula.Doeschot@Teledyne.com

• Web information

– http://www.teledynecetac.com/products/nebulizers/ aridus3