CETAC Aridus II, Руководство оператора

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5
1 Introduction
The Aridus II™ Desolvating Nebulizer System is designed primarily for ICP
mass spectrometry. The Aridus II™ incorporates a C-Flow PFA microconcentric
nebulizer, which provides low sample flow rates (approx. 50, 100, or 200
microliters/min.). The nebulizer is constructed entirely of inert materials and
is suited for use with acidic and alkaline solutions. Solutions may contain nitric
acid (HNO
3
), hydrochloric acid (HCl), hydrofluoric acid (HF), or ammonium
hydroxide (NH
4
OH).
Sensitivity is improved with the Aridus II™ system by enhancing analyte
transport efficiency and reducing solvent loading to the plasma. With
conventional pneumatic nebulization, injected water vapor causes oxide and
hydride polyatomic ion interferences in ICP-MS; organic solvent vapor loading
causes carbide polyatomic ion interferences as well as plasma instability and
carbon deposition on ICP-MS sampling cones. Using the Aridus II™ system for
sample introduction greatly reduces these problems. It is strongly noted that
the degree of sensitivity enhancement is dependent on the type of ICP-MS used
and the area of application.
Functionally, liquid sample is nebulized into a PFA spray chamber using a
C-Flow PFA microconcentric nebulizer operating at a sample uptake rate of
approximately 100 µL/min and an argon nebulizer gas flow rate of 0.7 to 1.1
L/min. The spray chamber is heated to help reduce the formation of solvent
droplets inside the spray chamber. The spray chamber is also drained by a
built-in peristaltic pump. The nebulizer gas flow then transports the aerosol
from the spray chamber to a heated inert fluoropolymer tubular membrane.
Solvent vapor passes through the membrane and is removed by an exterior
flow of Ar gas (sweep gas). Analyte continues through the middle of the
membrane tube to the ICP-MS instrument. An external view of the Aridus II™
Nebulizer System is shown in Figure 1-1.