EMENA How to choose the correct gas set up for GC 8am GMT  

Extracted text

Peak Scientific Gas Solutions
Choosing the right set-up for GC

Confidential, unpublished property of Peak Scientific Instruments Ltd. Do not duplicate or distribute. Use and distribution limited solely to authorized personnel. © 2019 Peak Scientific Instruments Ltd.

Gas generators provide a number of benefits

Convenience
Gas ondemand, no
cylinders to
change or
maintain
supply stocks

Consistency
Consistent gas
quality and
supply, no
impurities or
running out of
gas

Economy
Eliminate ongoing costs of
cylinders,
manage
lifetime running
costs

Safety
No pressurized
compressed
gas cylinders
in your lab

Green
No repeated
gas deliveries,
energy efficient

Gas Safety

Compressed gases can be
dangerous
▪

Nitrogen, helium, argon – Risk of asphyxiation

▪

Hydrogen, acetylene – Risk of fire/explosion

▪

Cylinders contain up to 9000L compressed gas

▪

1L LN2 produces 696L N2 gas

Inert gas safety

Effect of release of inert gas into the lab – O2 displacement

H2 Cylinders
▪

H2 cylinders are potentially dangerous
▪
▪

▪

Hydrogen and cylinder storage are increasingly regulated
▪

▪

▪

The cost of installation can be high as H2 cylinders need to be moved
further away from the lab

Be aware of the hidden costs of cylinders
▪
▪
▪
▪
▪

▪

9000L of stored gas at 200barg in a cylinder
150cc and 7barg in Precision SL

Delivery
Rental
Regulator replacement
Line maintenance
Frequent in-line trap replacement

Generators can be factored in to new lab installations to
save cost
Resources on cylinders and H2 safety

Safeguard your hydrogen
supply by using a generator
“A key benefit for us has been the elimination of the safety
hazards associated with compressed gas cylinder handling.”
Kerri Heckrow, NPD Lab Manager, Evergreen Packaging, NC, USA

Confidential, unpublished property of Peak Scientific Instruments Ltd. Do not duplicate or distribute. Use and distribution limited solely to authorized personnel. © 2019 Peak Scientific Instruments Ltd.
8/15/

H2 generator safety

▪ Low stored volume
▪ Low pressure
▪ Continuous monitoring of pressure
▪
▪

Over-pressure
Under-pressure

▪ Auto-shutdown
▪
▪

External leak
Internal leak

▪ Diagnostics at start-up
▪ Cell shut-down in case of problem

Calculating gas requirements for GC

Main detector gas requirements

▪

FID, FPD, NPD & SCD – Same basic function – burn a flame

▪

ECD – Make-up must be N2 Trace (hydrocarbon-free)

▪

TCD – reference gas is same as Carrier gas

Calculating the requirement

If no information is available, use worst-case flow rates to calculate
Eg. 3x FID = 150cc/min H2, 120cc/min N2, 1500cc/min Zero Air.
Eg. 2x FID + 1x ECD = 100cc/min H2, 140cc/min N2 Trace, 1000cc/min Zero Air

If method data is available:
Extract the information from the method information provided
At first sight this can look confusing
Look for key information

Acquisition methods

Acquisition methods

No flow
information
given – use
maximum flows
for calculations

Flow
information
given – use
indicated flows
for calculations

Calculations - Recap

1. Count the number of each detector type (remember some GCs may have 2
detectors) and add together the required flows of H2, N2 and Zero Air.
2. If specific flow details are not available, use ‘worst case’ flow rates.
3. Use the GC Gas Calculator to document the information and confirm with
the customer

Carrier gas

Carrier gas flow rates

The aim of calculating the carrier gas flow rate is to find the ‘total flow’
of the carrier gas.
The ‘total flow’ is the flow of carrier gas through the GC inlet
Knowing the ‘total flow’ allows us to recommend the correct
generator(s) to support the GC
Most GCs use a split/splitless injector
The calculation of flow rates differs depending on whether the method
uses split injection or splitless injection

Carrier Gas

Peak would always recommend either N2 Trace or H2 Trace
Zero air cannot be used for carrier gas
Can be more difficult to calculate if you try to go into too much detail…
Keep it simple…

Getting relevant flow information

Find the total carrier gas flow for each GC
If multiple methods used on 1 GC, calculate using the method with the highest total flow
Don’t try to calculate the Total flow – this should be easily available from the method

If helium carrier gas is used and being converted to hydrogen, the total flow
must be increased by 25%
For total flow of 100cc/min helium, the customer will require 125cc/min hydrogen

If the customer is using helium carrier gas and is converting to Nitrogen the
flow will stay the same

Acquisition methods

Confidential, unpublished property of Peak Scientific Instruments Ltd. Do not duplicate or distribute. Use and distribution limited solely to authorized personnel. © 2019 Peak Scientific Instruments Ltd.
8/15/

Acquisition methods

Acquisition methods

H2 Total flow = 287 cc/min
H2 detector flow = 35 cc/min
Total H2 requirement = 322 cc/min
N2 requirement = 30 cc/min
Zero Air requirement = 350 cc/min

Calculations - recap
1. Get the highest total flow for each GC or GC-MS
2. Count the number of each detector type (remember some GCs can
have 2 detectors) and add together the required flows of H2, N2 and
Zero Air.
If no info provided re. specific detector flow details, use ‘worst case’ flow rates.
If you do not know the total carrier gas flow rate try to find other methods online to get an
indication of approximate flow requirements
Add total flow and detector flow together

3. Use the GC Gas Calculator to document the information and confirm
the total gas requirement

Helium conversion to H2 &
resources available

There’s no need for us to have helium
cylinders on site and no need to change
air or helium cylinders at all, so that
reduces instrument down time and
cylinder manual handling risks.
Ian Bennington, Senior Analyst, Nerudia, UK

Assumptions

1. You/your customer wants to change carrier gas
2. You/your customer can change carrier gas
3. You/your customer understands that conversion might take some
time
4. You/your customer understands the process of conversion

Online Resources

▪ Agilent Method Translation software
▪ Restek EZGC method calculator
▪ Peak GC method list

Online Resources from Peak
▪
▪

Step by step guide to changing carrier gas
Application notes highlighting change of carrier gas for GC & GC-MS

www.peakscientific.com

Precision range

▪
▪
▪
▪
▪
▪

H2, N2 and ZA for carrier gas and detector gas
Stackable, modular
Low maintenance
Low cost of ownership
Easy to use – plug and play
Can be configured to meet your laboratory’s gas
requirements

Questions?

Q&A Session

Template Rev: 2.1

Thank you
www.peakscientific.com
Our Vision:
To exceed the expectation of our Customers, Colleagues and Suppliers

Our Values:
• Respect customer, supplier, colleague
• Restless constantly striving to improve

•
•

Freedom with responsibility
Fun & passion in everything we do

Confidential, unpublished property of Peak Scientific Instruments Ltd. Do not duplicate or distribute. Use and distribution limited solely to authorized personnel. © 2019 Peak Scientific Instruments Ltd.