Total Organic Carbon AnalyzerUsed to determine the total organic carbon (TOC) content in water or solid samples, the method of use includes three major steps: preparation before operation, operation process, and post-treatment after operation, as follows:
1、 Preparation before operation
Instrument status check
Check if the pre filter element of the waste discharge valve is clean. If it is dirty, it needs to be replaced to prevent sample residue from affecting the test results.
Check if there are any residual impurities in the crucible inside the combustion tube, and clean it if necessary to avoid interfering with sample combustion and detection.
If a salt containing sample has been measured before, the multi way valve needs to be cleaned to prevent residual salt contamination during subsequent testing.
Check if the pressure of the pure oxygen cylinder is sufficient (generally ≥ 0.1MPa) to ensure a stable supply of carrier gas.
Preparation of reagents and consumables
Prepare acidic reagents (such as 1% phosphoric acid), oxidants, and high-performance carbon free consumables (such as injection pads and drying tubes).
Check if the drying tube reagent has failed (if it turns white, it needs to be replaced), and if the halogen removal tube reagent has changed color (if it turns reddish brown, it needs to be replaced).
Sample pretreatment
Liquid sample: It needs to be uniform and free of sediment. When it is turbid or has a lot of particles, it needs to be filtered through a 0.45 μ m filter membrane to prevent blockage of the pipeline.
Solid samples: need to be ground to the appropriate particle size, accurately weighed to a certain amount (such as solid mode weighing generally does not exceed 30mg, carbon content is 5%), and wrapped in tin bags to prevent leakage.
2、 Operation process
Startup and initialization
Turn on the computer, printer, andTotal Organic Carbon AnalyzerHost, wait for instrument initialization (such as multi way valve, sample tray self-test reset).
Turn on the carrier gas (high-purity oxygen 99.995%), slowly increase the secondary pressure of the steel cylinder pressure reducing valve to 0.1MPa, and closely monitor the pressure changes. If the flow rate is high but the pressure cannot rise, the leakage fault needs to be investigated.
Software settings and parameter calibration
Start the operating software and select the operating mode consistent with the combustion tube (such as setting the liquid mode temperature to 850 ℃ and the solid mode temperature to 950 ℃).
Set operating parameters (such as pressure 1000mbar, flow 200ml/min) and wait for the instrument to heat up to the set value.
Perform calibration operation: Use a standard sample of known concentration to draw a calibration curve (correlation coefficient R ² ≥ 0.999) to ensure instrument response sensitivity.
Run quality control samples (QC) to verify the status of the instrument and ensure that the measurement results are within the allowable deviation range.
Sample determination
Establish sample sequence: Arrange RunIn (ultrapure water) and sample names in the software, select methods and parameters (such as line names).
Liquid mode:
Choose automatic injection, with a typical injection volume of 0.2-0.6ml (recommended 0.5ml).
Clean the acid pipeline twice before testing to avoid residual contamination.
Solid state mode:
Select semi-automatic injection and enter the sample quality and name.
Perform measurement: Place sample bottles in sequential order and trigger automatic or individual operation. Pay close attention to the operation status and data changes of the instrument.
Data processing and storage
The instrument automatically processes data, exports and saves it (such as in. mdb or. xls format), records sample information, testing time, methods, and parameters.
Check the accuracy of the data and make necessary corrections and verifications.
3、 Post operation processing
Instrument cooling and shutdown
After the analysis is completed, the host automatically enters sleep mode and waits for the furnace body to cool down to below 100 ℃ (if it does not cool down automatically, it can be operated through software).
Do not forcefully turn off the instrument during the cooling process to prevent damage to the heating components.
Shutdown sequence
Close the operating software (File>Exit), turn off the host power (on the right side of the instrument), and turn off the carrier gas (slowly close the valve to prevent sudden pressure changes).
Turn off the computer and printer.
Cleaning and maintenance
Rinse the injection needle, reactor, and tubing multiple times with carbon free water (such as ultrapure water) to prevent cross contamination.
Regularly replace the injection pad, check catalyst activity, and clean the NDIR detection cell.
Follow the maintenance manual and manufacturer's instructions for maintenance and repair.
4、 Precautions
Safety Specifications
It is prohibited to analyze samples containing strong acids, strong bases, organic solvents, toxic or explosive substances.
Pay attention to safety when using high-pressure oxygen to avoid gas leakage or sudden pressure changes.
Operation taboos
Unauthorized changes to instrument parameters are not allowed to prevent malfunctions.
When measuring high concentration samples (such as TOC>50ppm), dilution is required to avoid contaminating the pipeline.
Maintenance reminder
Regularly check the effectiveness of halogen absorption tubes (such as replacing white magnesium perchlorate or black silver wire).
After replacing the combustion tube or accessories, the Maintenance count needs to be reset in the software.