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SEMI C58-0305 © SEMI 2005 6 10.1.4.5 The results may not exceed s p ecificatio ns in Table 1 of this standard. 10.2 Nitrogen — This procedure i s for the determ ination of nitroge n in hy drogen usi ng a gas ch romatogra…
SEMI C58-0305 © SEMI 2005 5
9.5 Water — This procedure is for the determination of trace moisture (water) in hydrogen using a continuous
flowing piezoelectric hygrometer.
NOTE 6: The sampling system and hygrometer should be designed to operate under the sample pressure, or the sample pressure
should be reduced (by a regulator with a diaphragm of stainless steel or other suitable material) to accommodate the pressure
restrictions of the analytical hygrometer.
NOTE 7: Other hygrometers may also be used, e.g. CRDS, FTIR, TDLAS, and vibrating quartz.
9.5.1 Detection Limit — 0.1 ppm (vol/vol) at –90C (–130F).
9.5.2 Flow Requirements — Set the sample pressure and flow rate in accordance with the instrument
manufacturer’s instructions.
9.5.3 Calibration Standards — Construct a calibration curve which contains at least three points covering the range
of interest. Verify the standards employed independently by another analytical method.
9.5.4 Operating Procedure
9.5.4.1 Obtain a continuous flow sample of gas from the source using a clean and passivated stainless steel line
which has been purged dry after exposure to ambient moisture.
9.5.4.2 After prepurging with a dry gas, allow the sample gas to flow through the sampling system and the
piezoelectric moisture hygrometer until a stable reading is obtained.
9.5.4.3 Determine the moisture content of the hydrogen sample by comparing the reading to calibration curve. The
result may not exceed the specification in Table 1.
10 Analytical Procedures for Grade 5.7 Hydrogen (See Notes 1 and 2 in §9)
10.1 Carbon Monoxide and Carbon Dioxide — This procedure is for the determination of carbon monoxide and
carbon dioxide in hydrogen using a gas chromatograph with a flame ionization detector and methanizer.
10.1.1 Detection Limit — 50 ppb (mol/mol).
10.1.2 Instrument Parameters
10.1.2.1 Column: Porapak T or Z, 3 m (9.8 ft) by 3.2 mm (1/8 in) stainless steel; or Chromosorb 102, 2 m (6.6 ft)
by 3.2 mm stainless steel; or equivalent.
10.1.2.2 Carrier Flow: 30 mL/min helium.
10.1.2.3 Sample Volume: 0.5 to 2.0 mL.
10.1.2.4 Temperatures:
Detector 280°C
Column Oven 60°C
Methanizer 350°C
10.1.3 Calibration Standard — 1–5 ppm (mol/mol) carbon monoxide, 1–5 ppm (mol/mol) carbon dioxide, balance
hydrogen.
10.1.4 Operating Procedure
10.1.4.1 Inject the calibration standard into the column using a gas sampling valve. Record the retention times and
peak areas. The order of elution is carbon monoxide, carbon dioxide.
10.1.4.2 Inject the sample to be tested in the same manner as the calibration standard. Record the retention times
and peak areas.
10.1.4.3 Repeat ¶10.1.4.1.
10.1.4.4 Compare the average peak areas of the calibration standard to that of the hydrogen sample being tested.
Calculate the concentration of each impurity, using the formula below.
SEMI C58-0305 © SEMI 2005 6
10.1.4.5 The results may not exceed specifications in Table 1 of this standard.
10.2 Nitrogen — This procedure is for the determination of nitrogen in hydrogen using a gas chromatograph with a
helium ionization detector (see Figures 1 and 2).
NOTE 8: All carrier lines should be cleaned stainless steel.
NOTE 9: The carrier gas should be 99.9998% purity helium with less than 40 ppb carbon dioxide.
NOTE 10: Use a stainless steel pressure regulator with no pipe threads, PTFE thread sealant or other plastic seal components for
the carrier gas.
NOTE 11: Due to the extreme sensitivity of the helium ionization detector, it is imperative that the system be leak tested to 1 ×
10
–7
atm. cc/sec (helium) or lower with a helium leak detector.
NOTE 12: The hydrogen separator is the palladium tube type where the sample flows through a heated palladium tube through
which the hydrogen selectively diffuses separating it from the impurities which are carried to the column by the helium carrier
gas.
10.2.1 Detection Limit — 12 ppb.
10.2.2 Instrument Parameters
10.2.2.1 Columns:
Column 1
(Pre-Column):
Molecular sieve 5A, 60/80 Mesh, 2.4 m
(8 ft) by 3.2 mm (1/8 in), stainless steel,
or equivalent.
Column 2
(Analytical
Column):
Molecular sieve 5A, 60-80 Mesh, 2.4 m
by 3.2 mm, stainless steel, or
equivalent.
10.2.2.2 Carrier Flow: 40 mL/min helium.
10.2.2.3 Sample Volume: 1.0 mL.
10.2.2.4 Temperatures:
Detector 100°C
Column 50°C
Hydrogen Purifier 300°C
10.2.2.5 Determine the breakdown voltage of the detector. Set operating voltage at 10 volts below breakdown.
10.2.3 Calibration Standard — 2 ppm (mol/mol) nitrogen, balance hydrogen (99.9999% purity).
10.2.4 Operating Procedure
10.2.4.1 Set timing interval on sample select valve to 10 sec.
10.2.4.2 Set timing interval on gas sampling valve to 3 minutes.
10.2.4.3 Set timing interval #3 to 5 minutes.
10.2.4.4 Do not change the initial sample flow setting once established.
10.2.4.5 Obtain a continuous flow of the calibration standard using a clean stainless steel line [0.5 mm (0.02 in.]
ID).
10.2.4.6 Inject the calibration standard onto the column with the gas sampling valve. Record the retention times
and peak areas.
10.2.4.7 Repeat ¶10.2.4.6 until reproducibility of reading is better than 1% of full scale.
Sample Peak
Area
Standard Peak Area
Concentration
of Standard
Concentration
of Sample
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10.2.4.8 Inject the sample to be tested in the same manner as the calibration standard. Record the retention times
and peak areas.
10.2.4.9 Compare the average peak area of the hydrogen sample being tested to that of the calibration standard.
Calculate the concentration of nitrogen, using the formula below.
10.2.4.10 The result may not exceed the specification in Table 1 of this standard.
10.3 Oxygen — This procedure is for the determination of oxygen in hydrogen using a continuous flow analyzer
using an electrochemical method.
10.3.1 Detection Limit — 50 ppb (mol/mol).
10.3.2 Instrument Parameters — Set the sample pressure and flow rates in accordance with the instrument
manufacturer's instructions.
10.3.3 Calibration Standard — 1–10 ppm (mol/mol) oxygen in hydrogen or in accordance with the instrument
manufacturer’s instructions.
10.4 Operating Procedure
10.4.1 Do not change the initial sample flow setting once established.
10.4.1.1 Introduce hydrogen containing less than 2 ppm oxygen through a deoxygenation catalyst to verify that
there is no leakage of air into the system and to demonstrate that the detection limit can be achieved.
10.4.1.2 Introduce the calibration standard. Using the span adjust knob, set the needle (or output reading) to match
the level oxygen in the calibration gas.
10.4.1.3 Introduce hydrogen sample and record the oxygen reading. The result may not exceed the specification in
Table 1 of this standard.
10.5 Water — Use procedure in ¶9.5 for the determination of water.
10.6 Total Hydrocarbons — This procedure is for the determination of total hydrocarbons in hydrogen using a
continuous flow flame ionization detector equipped total hydrocarbon analyzer.
NOTE 13: The 0–1 ppm range can be used provided that zero and span gas standards in hydrogen with known levels of
hydrocarbons between 0–1 ppm are used in the calibration of the analyzer.
10.6.1 Detection Limit — 0.1 ppm (mol/mol).
10.6.2 Flow Requirements
10.6.2.1 High-purity, hydrocarbon-free (less than 1.0 ppm) hydrogen: 35–40 mL/min or 40% hydrogen in either
helium or nitrogen matrix at 75–80 mL/min.
10.6.2.2 Dry, hydrocarbon-free (less than 1.0 ppm) air: 350–400 mL/min.
10.6.2.3 Set sample flow rates in accordance with the instrument manufacturer's instructions.
10.6.3 Calibration Standards
10.6.3.1 Zero hydrogen with known quantity of hydrocarbons at 0.1 ppm level.
10.6.3.2 Span Gas — Hydrogen with known quantity (1–10 ppm) hydrocarbons.
10.6.4 Operating Procedure
10.6.4.1 Do not change the initial flow setting for hydrogen, air and sample once established.
10.6.4.2 Introduce the zero hydrogen with known quantity of hydrocarbons and, using the 0–10 ppm range, set the
needle (or output) to read the correct level using the zero adjust knob.
Sample Peak
Area
Standard Peak Area
Concentration
of Standard
Concentration
of Sample