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SEMI C60-0305 © SEMI 2005 4 9.2.4.4 Compare the average peak areas of the calibration standard to that of the nitrous oxide sample be ing tested. Calculate t he concentrations of carbon monoxide a nd carbon dioxide, usin…

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SEMI C60-0305 © SEMI 2005 3
9.1.2.4 Stop watch.
9.1.2.5 6 mm (1/4 in) flexible tubing.
9.1.3 Operating Procedure
9.1.3.1 Attach a suitable regulator to the cylinder outlet.
9.1.3.2 Connect the flowmeter to the regulator using flexible tubing.
9.1.3.3 Open the cylinder valve and purge the flowmeter with nitrous oxide.
9.1.3.4 After the line is thoroughly purged, stop the flow of nitrous oxide and attach the detector tube to the outlet
of the flowmeter.
9.1.3.5 Start the flow of nitrous oxide and set the flow rate to 100 mL/min. The pressure and temperature of the
sample must be within the tolerances specified by the manufacturer.
9.1.3.6 Pass 100 mL of nitrous oxide through the detector tube.
9.1.3.7 Determine the concentration of ammonia according to the detector tube manufacturer’s instructions. The
concentration may not exceed the specification in Table 1 of this standard.
9.2 Carbon Monoxide and Carbon Dioxide — This procedure is for the determination of carbon monoxide and
carbon dioxide in nitrous oxide using a gas chromatograph with a flame ionization detector and methanizer with
back flush, (see Figure A1-1).
NOTE 2: In order to prevent nitrous oxide interference, a helium backflush to vent is needed for 3–5 times the analysis time
(estimated to be 3–5 minutes). Because nitrous oxide is converted into ammonia in the methanizer, stainless steel (ss) is required;
copper tubing and fittings are not used. The backflush removes the nitrous oxide from Column No. 1 preparing the column for
the next sample. Careful timing is required to identify carbon monoxide and carbon dioxide distinguishing both from the time
methane would appear, if present. Carbon monoxide and carbon dioxide are converted to methane in the methanizer; therefore,
both will be detected by the FID detector at the specific times determined by the analytical sequence of the standard.
9.2.1 Detection Limit — 1 ppm (mol/mol), (50 ppb depending on conditions).
9.2.2 Instrument Parameters
9.2.2.1 Columns: Column 1: Porapak QS, 4.6 m (15 ft) by 5 mm (3/16 in) or equivalent. Column 2: Molecular
sieve 5A, 1.97 m (6 ft) by 5 mm, 80/100 mesh (reference only) or equivalent.
9.2.2.2 Carrier Flow: 30 mL/min helium.
9.2.2.3 Sample Volume: 0.5 to 2.0 mL.
9.2.2.4 Temperatures:
Detector 35°C
Column Oven 35°C
Methanizer 500°C
9.2.3 Calibration Standard — 1–5 ppm (mol/mol) carbon monoxide, 1–5 ppm (mol/mol) carbon dioxide, balance
nitrous oxide.
9.2.4 Operating Procedure
9.2.4.1 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, methane, carbon dioxide, and nitrous oxide. Back flush 18
minutes.
9.2.4.2 Inject the sample to be tested in same manner as the calibration standard. Record the retention times and
peak areas.
9.2.4.3 Repeat ¶9.2.4.1.
SEMI C60-0305 © SEMI 2005 4
9.2.4.4 Compare the average peak areas of the calibration standard to that of the nitrous oxide sample being tested.
Calculate the concentrations of carbon monoxide and carbon dioxide, using the formula below. The result may not
exceed the specification in Table 1 of this Standard.
Sample Pea
k
Area
Standard Peak Area
Concentration
of Standard
Concentration
of Sample
9.3 Hydrocarbons C
1
– C
5
— This procedure is for the determination of hydrocarbons C
1
– C
5
in nitrous oxide
using a gas chromatograph with a flame ionization detector.
9.3.1 Methane Determination
9.3.1.1 Detection Limit — 0.1 ppm (mol/mol).
9.3.1.2 Instrument Parameters
9.3.1.2.1 Column: 5A molecular sieve, 1.9 m (6 ft) by 6.4 mm (1/4 in) OD by 5.3 mm (0.210 in) ID stainless steel
or equivalent.
9.3.1.2.2 Carrier Flow: 25 mL/min helium.
9.3.1.2.3 Sample Volume: 5.0 mL.
9.3.1.2.4 Temperatures:
Detector 150°C
Column Oven 30°C
9.3.2 Ethane Determination
9.3.2.1 Detection Limit — 0.3 ppm (mole/mole).
9.3.2.2 Instrument Parameters
9.3.2.2.1 Column: Porapak Q, 1.9 m (6 ft ) by 6.4 mm (1/4 in) OD by 5.3 mm (0.210 in) ID stainless steel or
equivalent.
9.3.2.2.2 Carrier Flow: 50 mL/min helium.
9.3.2.2.3 Sample Volume: 1.0 mL.
9.3.2.2.4 Temperatures:
Detector 150°C
Column Oven 60°C
9.3.3 Ethylene, Propane, Acetylene, Propylene, n-butane, and n-pentane Determination
9.3.3.1 Detection Limit — 0.1 ppm (mole/mole).
9.3.3.2 Instrument Parameters
9.3.3.2.1 Column: Phenylisocyanate/Porasil C, 3 m (10 ft) by 4.8 mm (3/16 in) OD by 3.7 mm (0.147 in) ID
stainless steel or equivalent.
9.3.3.2.2 Carrier Flow: 25 mL/min helium.
9.3.3.2.3 Sample Volume: 1.0 mL.
9.3.3.2.4 Temperatures:
Detector 150°C
Column Oven 30°C
SEMI C60-0305 © SEMI 2005 5
9.3.4 Calibration Standards — 1–5 ppm (mol/mol) methane in helium, 1–5 ppm (mol/mol) ethane in helium, 1–5
ppm (mol/mol) ethylene, 1–5 ppm (mol/mol) propane, 1–5 ppm (mol/mol) acetylene, 1–5 ppm (mol/mol) propylene,
1–5 ppm (mol/mol) n-butane, and 1–5 ppm (mol/mol) n-pentane, balance in helium.
9.3.5 Operating Procedure
9.3.5.1 Inject the calibration standard into the column using a gas sampling valve. Record the retention time and
peak area.
9.3.5.2 Inject the sample to be tested in same manner as the calibration standard. Record the retention times and
peak areas.
9.3.5.3 Repeat ¶9.3.5.1.
9.3.5.4 Compare the average peak area of the calibration standard to that of the nitrous oxide sample being tested.
Calculate the concentration of hydrocarbons C
1
–C
5
, using the formula below. The result may not exceed the
specification in Table 1 of this Standard.
Sample Pea
k
Area
Standard Peak Area
Concentration
of Standard
Concentration
of Sample
9.4 Nitric Oxide — This procedure is for the determination of nitric oxide in nitrous oxide using
chemiluminescence. The detector shall have a photomultiplier tube capable of sensing the light emission of the
decaying nitrous oxide. The detector shall have variable attenuation, zero and span adjustments, display, and an
onboard ozone generator.
NOTE 3: This method does not determine nitrous oxide impurities.
9.4.1 Detection Limit — 0.1 ppm (mol/mol).
9.4.2 Instrument Parameters
9.4.2.1 Flow Requirements — Set the zero gas, span gas, and sample gas in accordance with the instrument
manufacturer’s instructions.
9.4.3 Calibration Standards
9.4.3.1 Zero argon (99.99% minimum) with less than 0.1 ppm nitric oxide.
9.4.3.2 The upper level argon span gas (99.99% minimum) not exceeding 5 times the concentration of the
specification.
9.4.3.3 The oxygen supplied to the ozone generator will contain less than 0.1 ppm nitric oxide.
9.4.4 Operating Procedure
9.4.4.1 Introduce the zero argon and set the instrument to zero with the zero adjust knob.
9.4.4.2 Introduce the span gas in argon and, using the span adjust knob, set the output reading to match the level of
nitric oxide in the span gas.
9.4.4.3 Repeat ¶9.4.4.1 and ¶9.4.4.2 until reproducibility of readings is better than 1% full scale.
9.4.4.4 Introduce the nitrous oxide sample into the analyzer and read the quantity of nitric oxide. The result may
not exceed the specification in table 1 of this standard.
9.5 Nitrogen and Oxygen — This procedure is for the determination of nitrogen and oxygen in nitrous oxide using a
gas chromatograph with a helium ionization detector.
9.5.1 Detection Limit — 0.5 ppm (mol/mol).
9.5.2 Instrument Parameters
9.5.2.1 Columns: Column 1: Porapak Q, 1.9 m (6 ft) by 3.2 mm (1/8 in) OD by 2.2 mm (0.085 in) ID stainless steel,
or equivalent. Column 2: Molecular sieve 5A, 2.4 m (8 ft) by 3.2 mm (1/8 in) OD by 2.2 mm (0.085 in) ID stainless
steel, or equivalent.