CETAC Technologies - - U-6000AT+ Ultrasonic Nebulizer

The U-6000AT+ adds a second desolvation stage (membrane desolvator) to the U-5000AT+ ultrasonic nebulizer. The membrane desolvator effectively removes solvent vapor (water and volatile organics) which escapes from the U-5000AT+ condensor (see diagram below). Solvent vapor permeates through a heated, porous PTFE membrane and is removed to vent by a flow of argon "sweep gas".

Improved Detection of K, Ca and Fe by ICP-MS

Water-based interferences (oxides and hydrides) in quadrupole ICP-MS are greatly reduced with the U-6000AT+. For example, the ArO⁺ interference at m/z=56 is sufficiently reduced to allow sub-ppb detection of Fe. Typical detection limits for K, Ca and Fe are listed below.

**U-6000AT+ Detection Limits**
Element	Interferent	Det. Limit (ng/L)
⁴⁴Ca	CO₂⁺	20
⁵⁶Fe	ArO⁺	5
³⁹K	ArH⁺	7

Note: Detection limits are based on 3 sigma.

Analysis of Volatile Organics by ICP-AES and ICP-MS

Volatile organic solvent analysis by ICP-AES or ICP-MS is compromised by a number of factors. Organic solvent vapors can destabilize and/or extinguish the plasma, carbon-based interferences can inhibit analyte detection, and carbon may build up on hardware components such as the ICP torch or ICP-MS sampling interface. The U-6000AT+ effectively removes organic solvent vapors allowing improved analysis of organics (see below.)

Comparison of Quadrupole ICP-MS Detection Limits with the U-6000AT+ (µg/L)
Element	Mass	Toluene	Isopropyl Alcohol	2% HNO₃
Mg	24	0.3	0.02	0.002
K	39	0.1	0.01	0.01
Cr	52	0.3	0.02	0.004
Fe	56	0.04	0.05	0.005
Ni	60	0.01	0.02	0.003
Zn	66	0.004	0.02	0.005
Pb	208	0.004	0.003	0.0006

Notes: Detection limits are based on 3 sigma.

Instrument used was an PerkinElmer ELAN 5000 ICP-MS.

Instrument used was a Thermo Jarrell Ash ICAP61.

Optional Blend Gas Accessory

An optional blend gas accessory (CETAC BGX-100) for the U-6000AT+ is available. The BGX-100 is equipped with a precision mass flow controller for addition of oxygen gas to the sample aerosol exiting the U-6000AT+. Oxygen addition can help prevent carbon buildup on the ICP torch and/or ICP-MS sampling interface. This accessory is recommended for the analysis of non-oxygenated solvents such as toluene and hexane. Generally the flow rate of oxygen required is only 10-20 mL/min. The BGX-100 is pictured below.

BGX-100

General Operating Conditions for Organics

For volatile organics, the ultrasonic nebulizer cooler is usually reduced to -10ºC to -15ºC. The lower temperature reduces the organic vapor loading to the membrane desolvator. Nebulizer gas flow (0.6 L/min - 1.1 L/min) and sweep gas flow (1.5 L/min - 4.0 L/min) can be adjusted through a wide range for best performance.

Download the "Signal Enhancement and Interference Reduction for Quadrupole ICP-MS" Technical Note (Adobe Acrobat required).

Specifications

Sample Uptake Rate:
Nebulizer Gas Flow:
Sweep Gas Flow:
Desolvation Heating Temp:
Desolvation Cooling Temp:
Membrane Module Heating Temp:
Power Requirement:
Ultrasonic Frequency:
Dimensions:
Weight:
Shipping Weight (with cart and accessories):

Download the Brochure (Adobe Acrobat required).