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Total Organic Carbon Analyzer User Guide
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Manual Information

User Guide Contents

• 50 mL Shimadzu autosampler glass vials, 10 pc
• 6 mL Shimadzu autosampler glass vials, 50 pc
• Wax paper
• Plastic ring caps for 50 mL autosampler vials
• Disposable caps for 6 mL autosampler vials
• 1000 mL, and 50 mL volumetric flask

Reagents

• Zero water: Fresh distilled water from the filtering system, carbon (TC) free, stored in a CO₂-free container. Use this water to rinse vials, make calibration standards, and run blanks. Do not expose the fresh distilled water to air to prevent dissolution of CO₂ into it.
• Potassium hydrogen phthalate, reagent grade
• Sodium hydrogen carbonate, reagent grade
• Sodium carbonate, reagent grade, heated 1 hr at 285°C and cooled in a dessicator
• Phosphoric acid, 25%

Standard Solutions
Standard solution concentrations are not stable because of instant absorption of CO2 from the atmosphere. To slow down this process, standard solutions should be stored in airtight containers in the refrigerator. 1000 ppm stock solutions can be stored for 2 months; 100 ppm diluted standards can be stored for 1 week.

• Total Carbon Stock
• 1000 mg C/L (1000 ppm C) stock solution: dissolve 2.125 g of potassium hydrogen phtalate in zero water in a 1L volumetric flask.
• At room temperature, potassium hydrogen phtalate doesn't dissolve in water very quickly, and it's grains are almost transparent, so the technician needs to make sure the solution is homogeneous before using it.
• 100 mg C/L (100 ppm) intermediate stock solution: dilute 10 mL of the the 1000 ppm standard stock solution in zero water in a 100 mL volumetric flask.
• Inorganic Carbon Stock
• 1000 mg C/L (1000 ppm C) stock solution: dissolve 3.50 g of sodium hydrogen carbonate and 4.41 g of sodium carbonate in zero water in a 1 L volumetric flask.
• 100 mg C/L (100 ppm C) intermediate stock solution: dilute 10 mL of the 1000 ppm standard stock solution in zero water in a 100 mL volumetric flask.

Hardware

• Shimadzu TOC-5000A instrument
• Shimadzu ASI-5000A Autosampler
• HPxw 4400 PC workstation (shared with GC2 system)
• Whatman/Parker Balston TOC 78-40 Gas Generator (UHP air tank can be substituted)
• TOC-5000A System Components.

TOC-5000A Analyzer
The TOC-5000A analyzer is configured to directly determine the content of total carbon (TC) and inorganic carbon (IC) in 2–10 mL aqueous samples within a carbon range of 200 ppb to 1000 ppm.
Total organic carbon (TOC) cannot be measured directly in samples but can be calculated:
TOC = TC – IC
Samples run on the TOC-5000A system are analyzed for TC and IC sequentially, followed by automatic software calculation of TOC.
Figures 1-2 and 1-3 show the general configuration of the TOC-5000A hardware.

• Schematic of TOC-5000A Interior (Front View).
• Photograph of TOC-5000A Interior (Front View).

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  Close-up Front View Flow Lines in Upper Right.

Autosampler
The autosampler allows automated carbon analysis in multiple samples.

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  Autosampler Back View.
• Autosampler Closeup.

Gas Generator
The Parker Balston (Whatman)78-40 TOC Gas Generator (Figure 1-7)converts compressed air into high purity carrier/combustion gas for the TOC analyzer with hydrocarbon levels < 0.1 ppm and CO₂ level < 1 ppm.
The Gas Generator should be fed from the air compressor, not from an air tank, because of the high rate of air consumption. Incoming air should be relatively free of dust and water (typical air compressor produced air should meet these requirements).

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  TOC Gas Generator.

• 100 ppb: 0.1 mL of 100 ppm + 99.9 mL zero water
• 500 ppb: 0.5 mL of 100 ppm + 99.5 mL zero water
• 1 ppm: 1.0 mL of 100 ppm + 99 mL zero water
• 2 ppm: 2.0 mL of 100 ppm + 98 mL zero water
• 5 ppm: 5.0 mL of 100 ppm + 95 mL zero water

Inorganic Carbon
In a 100 mL volumetric flask, make up the following calibration levels to bracket general expected IC levels from the 100 ppm intermediate stock solution:

• 100 ppb: 0.1 mL of 100 ppm + 99.9 mL zero water
• 500 ppb: 0.5 mL of 100 ppm + 99.5 mL zero water
• 1 ppm: 1.0 mL of 100 ppm + 99 mL zero water
• 2 ppm: 2.0 mL of 100 ppm + 98 mL zero water
• 5 ppm: 5.0 mL of 100 ppm + 95 mL zero water

• Calibration Sample Table.

• Calibration Curve List Dialog Box.

• Calibration Curve Conditions Tab.

Running a Calibration Curve

Evaluating the Calibration Curve

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Running a Calibration Verification

Sample Preparation
Overview
Samples are prepared by squeezing interstitial waters from sediment cores. Total organic carbon is run on unfiltered interstitial water samples; dissolved organic carbon (DOC) is run on interstitial water samples filtered through a 0.45 µm membrane.
Interstitial waters are diluted ~1:5 before running on the TOC analyzer and the analyzer is calibrated for quantitation of sample results. Running samples involves the following steps:

Preparing TOC Analyzer Hardware

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  Software TOC Control Screen with Blank Sample Table.

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  IC Method Tabs.

Calibration
Calibration Verification
Precision
Accuracy

• Handle TOC oven with caution and carefully watch all warning and safety signs around and inside instrument.
• Carefully read all three Shimatzu TOC/ASI/Software manuals, which are provided both in hard and soft copies about issues related to personal and instrument safety.
• Prepare 25% phosphoric acid from concentrated phosphoric acid under while wearing acid gloves, closed-toed shoes, protective clothing, and safety glasses.
• Label interim and stock solutions with the chemical name, concentration, operator name, and date.
• Ensure proper operation with gas tanks:
• Prevent the tank from dropping by tightening it with strong belt to the stable support
• Never attempt to disassemble the high pressure regulator on the top of the tank
• Do not disassemble gas tubing until inside pressure drops to close to atmospheric pressure; uptight fitting slightly and let pressure release from gas lines before further operations.
• Do not place your fingers or other parts of your body under autosampler needle working area, especially during autosampler operation.
• Follow the main safety rules for operation with electronics:
• check proper cable setting
• Avoid contact with electronic parts inside instrument during "power on" condition

Pollution Prevention
Waste Management

• The contents of the waste bottle (when it's full) need to be checked for neutral pH, corrected if necessary to neutral point with sodium carbonate, and disposed to the sink.

• Check water level in humidifier and dehumidifier pot
• Check acid level in IC reaction vessel
• Inspect drain line positions and empty drain jar, if necessary
• Refill autosampler rinse bottle with distilled water
• Keep a lint-free environment when cleaning; even small sized particles can clog the sample needle, tubing, or 4-port valve!
• Use only distilled water for cleaning procedures--no other solvents. Wipe surfaces with a water-dampened cloth.
• Always make sure the oven has cooled down (~30 min) before the TOC ventilators go off.
• Proper care must be taken at all times when the TOC is switched off. Usually the TOC combustion oven is working when instrument power with ventilator is going down.
• In case of an emergency power black out, remove the TOC cover panels to let heat escape from the oven without significant warming-up of electronic and plastic TOC parts.

Weekly/Monthly

• Check the gas lines for leaks by comparing flow-meter readings at incoming and outgoing (L-line for CO₂ absorber) tubing connections.
• Note: All connections in the TOC are finger-tight, so NO TOOLS should be applied to avoid improper pressure!

Annual

• Replace CO2 absorber (PN 630-00999).

When Needed

• Replace halogen scrubber (PN 630-00992) when it turns blue, green, or black. After replacement, wait about an hour for baseline to stabilize.
• Replace or regenerate high-sensitivity TC catalyst when sensitivity and repeatablility become unacceptable.
• Wash TC combustion tube interior with 1+2 HCl solution, rinse in water, and dry when washing or replacing catalyst.
• Replace TC combustion tube when it becomes broken or cracked or leaks gas. Regardless of the color or transparency of the glass tube, it can be used until it begins to leak.

Hardware Troubleshooting
Unstable Baseline

• Leak in carrier gas
• TC catalyst needs to be replaced
• Dehumidifier not operating correctly
• Environmental: vitration, ambient temperature, power supply
• NDIR defective

Bubbles in Sample/Syringe Tubing
Bubbles in the sample tubing affect the accuracy of an analysis. If bubbles are noted in the sample tubing, they need to be removed before beginning an analysis.

Peaks Are Too Broad or Are Tailing
Tailing should be considered a significant issue. Tailing is identifed by a T in the real-time window in the Notes column and means the integration was cut before the peaks curve reached the baseline. Tailing peaks can be cause by

• Contaminated tubing: check a blank analysis for a contamination peak
• Clogged or leaking tubing:
• Leaking and restricted tubing affect the outlet (CO₂ absorber L-line) flow rate. Check both the flowmeter inlet and outlet openings because the TOC and laboratory flow meters may be different. Lower flow at the outlet suggests and clog or leak that must be isolated and fixed.
• Connect both L and S tubes of the CO₂ absorber in one line. In this configuration, the operator should see immediate bubbling in the dehumidifier drain container, meaning the line has no major leak and all gas is escaping through the drain. If no bubbling occurs that means the system has a leak or is clogged. The most common places to check for the flow rate inside the instrument are the connections before the combustion tube and the cooling coil outlet.

No Peaks

• The most common reason for an absent peak is a TOC flow line leak. Check the air supply line/carrier gas flow reading and make sure the humidifier stopper is tightly plugged.

TOC/ASI Normal Analysis Routine Stopped in Middle of Run without Operator Command
This may happen because of a hardware malfunction (e.g., bent needle or 4-port valve sticking.

• If the needle is bent, unscrew it and remove it from the autosampler arm. Usually the needle can be straightened. If not, then replace the needle. When replacing the needle in the autosampler arm, ensure the needle height and alignment above the rinse/sample vials are positioned correctly before tightening down the arm.
• If the 4-port valve is stuck, take it apart and check for breakage or particle contamination, as those can cause rotation failure.

Autosampler Troubleshooting
Regenerating TC Catalyst

Replacing Rinse Water Pump Head

Removing the Syringe

Shimadzu Technical Support

• 1-800-477-1227, ext 1442
• Leonardo Ponds

• Make sure previous windows are closed; software version is old and can operate only with one window open in the TOC Control screen
• Close/reopen TOC Control window
• Restart software/computer

Gas Generator Troubleshooting

• Normally the Gas Generator should be connected to the TOC through blue plastic tubing. In this case, the outlet flow rate of the Gas Generator is controlled by the TOC flow controller (150 mL/min). If the Gas Generator outlet flow line is disconnected and open to the atmosphere, the flow rate will vary, depending on the inlet pressure. When outlet flow is higher than 1250 mL/min, the Gas Generator front panel overflow indication light will turn yellow. In this situation, the technician should correct the flow rate, because overflow conditions will cause the Gas Generator catalyst module to cool and will not produce appropriate quality air.
• The outlet flow reading may drop below 150 mL/min or have no flow at all. This will significantly affect the TOC flow rate. The most common reason for such a malfunction is the final filter or other filters are clogged. Replace the filters to fix this problem.
• If the CHECK SYSTEM light located on the bottom of the front panel starts flashing, and especially when it turns to a permanent yellow light, the catalyst unit needs to be exchanged for a new one. Normally happens once every 2–3 yr of constant Gas Generator use.
• Every 4–5 min a pneumatic switch triggers audibly between the dryer and co-remover towers on the back of the Gas Generator. If the interval time between switches is ~10 min, there may be problems with the Gas Generator.

• New File: Closes the current Sample Table and brings up a blank Sample Table.
• Open File: Opens a saved Sample Table, which replaces the current Sample Table. Select a .toc file in the dialog box.
• Save File: Saves the data in the current Sample Table.
• Cut: Removes data from highlighted cells in a table and saves them to the clipboard.
• Copy: Copies data from highlighted cells in a table and saves them to the clipboard.
• Paste: Copies the contents of the clipboard to a selected location in a table.
• Print: Sends data from currently displayed window to the printer.
• Run Time Report: Toggles Run Time Report on and off.
• Configure by selecting Report > Run Time Report.
• Recalculate: Recalculates the currently displayed sample run after applying a new calibration curve or excluding injections from the Injection Table.
• Show Injection Table: Displays the Injection Table.
• Highlight a row in a Sample Table to indicate which sample run to show in the Injection Table.
• Show Peak Profile: Displays a Peak Profile graph.
• Highlight a row in a Sample Table to indicate which sample run to display.
• To display a peak profile for an individual injection, highlight a row in the Injection Table.
• Show Calibration Curve: Displays calibration curve data for a specific sample run.
• Highlight a row in the Sample Table to indicate which calibration curve to display.
• Exclude: Excludes the selected sample or injection from a calculation or re-includes a previously excluded sample.
• Real Time Window: Opens the Real Time analysis window.
• Connect/Disconnect Instrument: Opens or closes the elctronic connection between the instrument and the computer.

Instrument Status

Analysis Status

Instrument Status Bar
Instrument Control Bar Buttons

• Start: starts measurement
• Stop: stops the measurement after the current injection is complete
• Pause: pauses instrument operation after current injection is complete
• Halt: immediately interrupts measurement
• Continue: continues interrupted measurement sequence
• Peak Stop: stops current measurement