Page 217 - Praxair - Specialty Gases and Equipment Reference Guide

Laboratories

Analytical Instrumentation

Praxair’s Gas Grade Recommendations
Analytical Method Instrument Page Analytical Range Type of Analysis
Detector Gases Number < 100 ppm > 100 ppm Impurity Considerations
Optical Spectrometry – Atomic Emission
ICP Ar B •26 AR 4.8IC AR 4.8IC Elemental Analysis
(Inductively Coupled Plasma) LAr B •82 AR 4.8IC AR 4.8IC (see application note below)
N 2 B •65 NI 5.0UH NI 5.0UH
Flame Air B •24 AI 0.0Z AI 0.0Z Elemental Analysis
C 2 H 2 B •23 AC 2.6AA AC 2.6AA
n-C 4 H 10 B •31 BU 2.5IS BU 2.5IS
H 2 B •54 HY 4.5Z HY 4.5Z
N 2 O B •69 NS 2.5AA NS 2.5AA
Arc or Spark Ar B •26 AR 5.0UH AR 4.8 Elemental Analysis
H 2 B •54 HY 5.0UH HY 4.5Z
5% Ar in H 2 D •218 IG NC6 IG NC6
Optical Spectrometry – Chemiluminescence
Chemiluminescence Air B •24 AI 0.0CE AI 0.0CE Atmospheric Pollutants –
N 2 B •65 NI 5.5CE NI 5.5CE NOx, SOx, O 3
O 2 B •70 OX 4.3UH OX 4.3UH
Optical Spectrometry – Fluorescence
XRF 10% CH 4 in Ar D •218 IG P10 IG P10 Elemental Analysis
(X-Ray Flourescence) 1.3% n-C 4 H 10 D •218 IG NC4 IG NC4
in He
Laboratories
D •218 IG NC5 IG NC5
0.95% i-C 4 H 10
in He
LN 2 B •85 NI 4.8LC NI 4.8LC
UVF Air B •24 AI 0.0VC AI 0.0VC SO 2 - H 2 S - Organic Compounds
(Ultra-Violet Fluorescence) N 2 B •65 NI 5.5CE NI 5.5CE

Application Note:
Using Argon with ICP

Inductively coupled plasma (ICP) is a popular means of of argon grades to meet the requirements of most instru-
preparing analytes for atomic emission spectrometry (ICP- ments; the AR4.8IC grade is most commonly used. Argon
AES) and mass spectrometry (ICP-MS). In both methods, is purified from atmospheric air and may contain trace
the high temperature, ionizing environment of the plasma levels of krypton, which can interfere with ICP-MS analyses
converts analyte molecules into excited-state atoms and for selenium and strontium. Argon flow rates for ICP often
ions. AES methods identify and quantify elements in the exceed 10 liters per minute, making these applications good
analyte on the basis of the electromagnetic radiation emitted candidates for cryogenic liquid supply options. Liquid supply
by the excited-state species, while MS methods separate via dewars or microbulk can reduce unit costs and disrup-
and quantify the ions on the basis of their mass-to-charge tions associated with changing cylinders. Cylinders better
ratio. Argon is almost always used as the plasma gas for preserve product and lab space when ICP instrument usage
ICP applications. High purity argon is required to sustain is infrequent. Praxair can help ICP users choose the right
a robust plasma, prevent instrument contamination, and grades and supply options for their needs.
avoid interferences with analytes. Praxair offers a variety

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