Measures and Proposals to Reduce Helium Gas Consumption
There is an increased focus on lowering running costs and reducing the burden on the environment. Helium gas (He) is a precious resource and must be used carefully by consuming as little of it as possible. Shimadzu GC-MS are equipped with functions to reduce helium gas consumption. Here, we introduce details of these functions and their setting methods.
Saving Carrier Gas during Analysis (Carrier Gas Saver Mode)
High-concentration target samples are analyzed using a large split ratio in order to reduce the amount of sample introduced into the column. However, during normal GC-MS analysis it is not necessary to maintain the large split ratio throughout the entire analysis time, as the sample is vaporized immediately after injection and then transported by the carrier gas. The carrier gas saver mode changes the split ratio at a specified time after sample injection to reduce the helium gas consumption. This function is introduced here. The carrier gas saver mode is offered as standard with the GCMS-TQ Series and all models in the GCMS-QP2020/QP2010 series.
In this example, the carrier gas saver mode reduces the split flow rate from 175 mL/minute to 25 mL/minute one minute after the sample is injected. When an autoinjector is used, the reduced split flow rate is maintained throughout the analytical run and until analysis starts the next day.
This function reduces helium gas consumption by approximately 83 % per analysis under the conditions below.
Analysis time: 30 minutes, Split ratio: 100
Carrier gas saver function: Split ratio 15 after 1 minute
Column temperature: 100 °C
Column: Inner diameter 0.25 mm, length 30 m, thickness 0.25 μm
Reduction in carrier gas consumption during analysis standby and after completion of analysis (ecology mode and shutdown method)
Helium gas is still consumed after analysis is complete. When the ecology mode or the shutdown method is used, the quantity consumed can be reduced.
When the model used is
GCMS-TQ Series, GCMS-QP2020, GCMS-QP2010 Ultra/SE → 1. Ecology mode
GCMS-QP2010 Plus, GCMS-QP2010S, GCMS-QP2010 → 2. Shutdown method
1. Ecology Mode (GCMS-TQ Series, GCMS-QP2020, GCMS-QP2010 Ultra/SE)
The ecology mode is offered as standard with the GCMS-TQ Series, GCMS-QP2020 and GCMS-QP2010 Ultra/SE models to reduce unnecessary gas and electricity consumption during analysis standby and after continuous analysis is complete.
2. Shutdown Method (GCMS-QP2010 Plus, GCMS-QP2010S, GCMS-QP2010)
While the GCMS-QP2010 Plus, GCMS-QP2010S, and GCMS-QP2010 do not offer the ecology mode, a shutdown method can be set to reduce the helium gas consumption in virtually the same way as the ecology mode does.
ECO Simulation Calculates the Savings
The actual helium gas savings will differ according to the operation environment (analysis conditions) used by the customer. ECO Simulation can be used to calculate the effects of the ecology mode. It accurately determines the results achieved by the ecology mode in a customer's laboratory based on specified conditions.
Note 1: It may not be possible to use the carrier gas saver mode, ecology mode, or the shutdown method when a pretreatment unit is connected. If you use a GC-MS with a pretreatment unit connected, should consult your Shimadzu representative.
Note 2: Consult your Shimadzu representative if you wish to use hydrogen as the carrier gas.
Using a Safe Hydrogen Gas Supply and/ or Hydrogen Gas Generator Are Recommended
A hydrogen gas generator is far safer than gas cylinders. As the hydrogen gas is generated by the electrolysis of water, the gas flow rate cannot exceed a certain level even if a gas leak occurs. Using a hydrogen gas generator eliminates the need for dangerous and expensive hydrogen cylinders.