Versions Compared

Key

  • This line was added.
  • This line was removed.
  • Formatting was changed.

Total Organic Carbon Analyzer User Guide (from TOC_UG_20100429)
This file is for editing content only! Cross-references and hyperlinks do not work. Use track changes and return file to peters@iodp.tamu.edu with copy to techdoc@iodp.tamu.edu.

Manual Information


Author(s):

Y. Vasilyeva (08/29/08)

Reviewer(s):

 


Editor(s):

K. Graber (7/14/08), J. Hesse

Manager Approval (Name, Title, Date):

 


Audience:

RS, Scientists

Origination Date:

 


Current Version:

Draft 12/08/08 LLP

Revised:

 


Domain:

Chemistry

Analysis:

Carbon/Carbonate Analysis



User Guide Contents


Topic

See page…

Introduction

2

Apparatus, Reagents, & Materials

3

Instrument Calibration/Verification

9

Sample Preparation

12

Sample Analysis

17

Quality Assurance/Quality Control

18

LIMS Integration

19

Health, Safety, & Environment

20

Maintenance & Troubleshooting

21

Software Guide

25


Introduction
Theory of Method
The Total Organic Carbon (TOC) instrument analyzes liquid samples by physically combusting the samples at 680°C for TOC or by chemically combusting the samples in 25% phosphoric acid for inorganic carbon (IC). The instrument measures the amount of carbon degraded to CO2 using nondispersive infrared gas analysis at 4.3 µm wavelength, calculated based on Lambert-Beer's law.
Total Carbon (TC)
To analyze for Total Carbon (TC) a sample is delivered to the TC combustion tube filled with platinum catalyst and heated to 680°C. Carrier gas (purified air or oxygen) , along with the CO2 generated by combustion, flows through the reaction vessel to the dehumidifier and scrubber, where it is cooled, dried, and purified. It then it passes into the nondispersive infrared detector, which generates an analog signal that is digitized and processed by the TOC Control software. The peak area is proportional to the concentration of total carbon in the sample.
Inorganic Carbon (IC)
During inorganic carbon analysis the liquid sample is introduced into the reaction vessel, which is half filled with 25% phosphoric acid. The sample is purged with carrier gas (high purity air) through the acid solution. The phosphoric acid reacts only with inorganic carbon components (CO32- and HCO3), transforming them to CO2. The CO2 is carried fromthe IC vessel through the dehumidifier and scrubber to the NDIR detector.
Total Organic Carbon
TOC concentration can be obtained by subtracting the IC concentration from the TC concentration.
Note: Before operating the TOC system every operator must get either additional training from a senior technician or carefully study all three manufacturer TOC/ASI/Software manuals.
Apparatus, Reagents, & Materials
Laboratory Apparatus

...

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.


Instrument

Specification

Method

Combustion/nondispersive infrared gas analysis

Combustion temperature

680°C

Measurement range

4 ppb to 4000 ppm

Anaysis time

2–3 min each for TC and IC

Repeatability

<2000 ppm: 1% of full scale
2000–4000 ppm: 2% of full scale

Sample introduction

Automatic injector

Injection volume

50–2000 µL

Ambient temperature

5°–35°C

Dimensions

480 mm W x 520 mm D x 480 mm H

Weight

~46 kg



Figure 1-2. Schematic of TOC-5000A Interior (Front View).

...

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).

...

Setting up the Sample Table for Calibration Curve


Step

Action

    1

From the TOC Control screen select File > Open Sample Table and open a new or previously saved calibration Sample Table (Fig 8).

    1

Click in the first line of the Sample Table and select Edit > Insert Standard.

    2

On the TOC Control screen toolbar, select View > Calibration Curve List.

    3

On the Calibration Curve List dialog box, select New (Fig 9).

    4

On the Conditions tab (Fig 10), enter the following:

  • Title and File Name for the calibration
  • Analysis Type (TC or IC)
  • Change Calculation Method to Lin. Regression without Zero Shift (FIG).
  • The Range and Injection Volume fields will be autofilled after completing information in the Data tab.
    5

Select the Data tab and enter information requested into the data table.

    6

Click OK and save the calibration information and Yes to use as method default parameters.

    7

Save the Sample Table.


Figure 1-8. Calibration Sample Table.

...

Running a Calibration Curve


Step

Action

    1

Place calibration curve standards in autosampler spaces S1–S8.

    2

Verify status of instrument and baseline: View > Background Monitor then close Background Monitor screen.

    3

Select Measure > Start or click Start on the instrument control bar. When the Standby screen opens, select Keep Running and click OK.

    4

To monitor the status of the measurements, select View > Realtime Window or select Realtime Window on the toolbar.

    5

When the calibration runs are complete the instrument status bar will indicate Ready.


Evaluating the Calibration Curve


Step

Action

    1

Select View > Calibration Curve or click the Calibration Curve button on the toolbar.

    2

Select the Curve tab to see the curve data in graphical format. . [Author: Need a screen shot of this.]


    3

Check the correlation coefficient (R2), which was calculated using the linear relationship of the concentration vs. area. R2 > 0.995 indicates an acceptable calibration.

    4

Select the Data tab to view standard deviation and coefficient of variation statistics. [Author: Need screen shot.]


    5

Individual peaks or injections can be viewed using View > Peak Profile > Display.

    6

If the calibration is acceptable, specify the calibration file (CAL) name in the method and close the Calibration window.


Running a Calibration Verification


Step

Action

    1

Run a midpoint curve standard as an "unknown" sample in the Sample Table.

    2

Apply the calibration curve to calculate the sample results.

    3

Open View > Injection Table or click the Injections button on the toolbar to examine the sample results in the Concentration column and the result of the Outlier Test. For acceptable calibration verification, CV should be >0.90.

    4

Close the Injection Table screen.


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:


Step

Action

    5

Set up hardware (see Setting up the Sample Table for Calibration Curve)

    6

Set up software (see Preparing TOC Software )

    7

Set up autosampler (see Preparing the Autosampler)

    8

Set up sample table (see Setting up a Sample Table and Selecting a Calibration Curve)

    9

Run samples (see Running Samples)


Preparing TOC Analyzer Hardware


Step

Action

    1

Make sure tubing and cables are connected properly to the instrument.

    2

Check compressed air feed line (65–80 psi) for the Gas Generator (if using an ultra-high purity air tank the delivery pressure be set to 80 psi (not to exceed 100 psi).

    3

Check that the Gas Generator is in ready condition. THC light green and no CHECK SYSTEM/ OVERFLOW lights on. [Author: Need photo of green light on Gas Generator.]


    4

Fill the humidifier with distilled water until the water level is between the white lines. Make sure the rubber stopper is fully plugged in.

    5

Fill IC vessel with 75–100 mL of 25% phosphoric acid solution.

    6

Make sure all drain lines have a negative slope alignment. Empty the drain container, if required.

    7

Check position of three-way cock arm. The cock arm should be in the left position (Fig 4).

    8

Ensure TOC main power switch is turned on and black switch on front top right side (behind instrument door) is in PC CONTROL position.


Figure 1-11. Software TOC Control Screen with Blank Sample Table.



Preparing TOC Software


Step

Action

    1

Click on the TOC Control icon on the computer desktop (see #1 on Fig 11). Type DAQ for username and password to open the TOC Control screen.

    2

From the Toolbar on the TOC Control screen, select Measure > Connect (#3 on Fig 11), and at the bottom of the Control screen click the TOC button (#4 on Fig 11).
The message bar (#5 on Fig 11) should say Connected.

    3

Check the carrier gas flow meter and pressure gage on the front panel of the TOC analyzer.

[Author: Need a photo of this meter and pressure gage.]


Flow should be 150 mL/min, and pressure should be ~450 kPa. Adjust flow or pressure to target values using the Carrier gas pressure controller and Carrier gas flow controller next to the flow meter (see Fig 4).


4

On the TOC Control screen, select View > Background Monitor (#6 on Fig 11) to open a background window.

5

Wait ~2 min and then make sure all parameters read OK on screen (exception: oven temperature will take ~30 min to reach 680°C).

[Author: Need a screen shot of the Background window.]



Close the Background window.


6

On the TOC Control screen select Options > Instrument Conditions (#7 on Fig 1) to set up and/or verify TOC, ASI, and RS232 settings as follows:

TOC

  • Furnace = on
  • Auto ranging = on
  • Inj volume = on
  • Auto regenerating = on
  • Syringe size = 250 µm

ASI

  • ASI used = on
  • High sensitivity vials = on
  • Rinse = on
  • No. of washes = 4

RS232

  • RS232 = COM1
  • Baud rate = 2400
  • Parity = none
  • Stop bits = 1


Preparing the Autosampler


Step

Action

    1

Fill autosampler rinse bottle (Fig 5) with fresh zero water.

2

Fill high-sensitivity 50 mL autosampler glass vial with zero water and place it to S1 tray position. Remove tray cover or make sure it's in the correct position.

  • Each vial in the autosampler tray must be filled to the top and covered immediately with wax paper or sealed with special caps to prevent CO2 penetration. After the sealed surface is pierced by the autosampler needle, the vials will remain usable for only a limited time (usually a few hours).
    3

Remove bubbles from the syringe (Detect Zero point): on the TOC Control screen select Options > Maintenance > Zero point detection.
The ASI arm and tray will start moving and the syringe/4-port valve will perform the bubble removing procedure.


Setting up a Sample Table and Selecting a Calibration Curve


Step

Action

    1

From the TOC Control screen select File > Open Sample Table to create a new Sample Table (#8 in Fig 11) or open an old Sample Table (#9 in Fig 8).

    2

Fill in the Sample Table with sample type, name, ID, and analysis.

    3

To specify a method on the Sample Table, select View > Methods on the TOC Control screen to open a saved method or create a new method.

    4

Fill in information on the General and Method tabs of the Method screen (Fig 12).

    5

To specify a calibration curve to apply to the samples, select View > Calibration on the TOC Control screen to open a dialog box showing a list of calibration curves saved in the CALIBR folder (Fig 9).

    6

On the Calibration Curve List dialog box, click Open to select a saved calibration curve.

    7

Save the Sample Table.


Figure 1-12. IC Method Tabs.

...

Sample Analysis


Running Samples


Step

Action

    1

Load the sample vials into the autosampler in positions that correspond to the Sample Table.

    2

Verify status of instrument and baseline: View > Background Monitor, then close Background Monitor screen.

    3

Select Measure > Start or click Start on the instrument control bar. When the Standby screen opens, select Keep Running and click OK.

    4

To monitor the status of the measurements, select View > Realtime Window or select Realtime Window on the toolbar.

    5

When the sample runs are complete the instrument status bar will indicate Ready.

    6

Sample results calculated from the loaded calibration file will display in the Sample Table Mean Area and Result columns.


Quality Assurance/Quality Control

...


Blanks
The TOC analyzer has an automated TC Blank Check Program that runs zero water blanks from 4 different vials a total of 10 times.


Step

Action

    1

Place vials filled with zero water in autosampler positions S1–S4.

    2

On the autosampler control panel, open the Maintenance screen and select TC Blank Check.

    3

The autosampler injects S1 twice, S2 three times, S3 three times, and S4 twice and then returns to Home.



Calibration
Calibration Verification
Precision
Accuracy

...


Overview
TC/IC/TOC analysis results are manually entered into the LabWare LIMS client by the technical staff once the scientist(s) is (are) finished reducing the data.
LIMS Components
Results are stored in the LIMS database associated with an analysis code and an analysis component. Analysis codes and their components, definitions, and units are listed below.


Analysis

Component

Definition

Unit

TOC

carbon_total

Concentration

ppm

 


inorganic_carbon_total

Concentration

ppm

 


organic_carbon_total

Concentration

ppm

 


run_test

link to calibration test

 


TOC_QAQC

carbon_total

Concentration

ppm

 


inorganic_carbon_total

Concentration

ppm

 


organic_carbon_total

Concentration

ppm

 


run_test

link to calibration test

 

 



cal_filename

calibration file

 

 

 



method_filename

 

 




run_filename

 

 





Health, Safety, & Environment

...

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.


Step

Action

    1

Select Options > Maintenance > Mechanical Check > TOC.

    2

Move the syringe plunger up and down using the plunger height control on the left while changing the position of the 4-port valve to Sample, TC port, or IC port.

    3

When the sample goes to the TC/IC waste line, do not bring the syringe plunger all the way up.


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

...

Autosampler Troubleshooting


Regenerating TC Catalyst


Step

Action

    1

Place a vial containing 2 mM HCl in position S1.

    2

Open the autosampler Maintenance screen and select Regeneration of TC Catalyst.

    3

The sampling needle moves to the S1 vial then to the rinse water receptacle and rinses the injection needle 3 times.


Replacing Rinse Water Pump Head


Step

Action

    1

After ~300 hr running time, replace the pump head assembly (PN 042-00405-11).

    2

Take off the small cover attached to the side of the autosampler.

    3

Pull out the pump head (white plastic) from the pump body (black plastic) by picking the claws of both sides with fingers.

    4

Replace the pump head by disconnecting the elastic tubes from the Teflon tubes and connecting new ones.

    5

Remount the pump head and cover.


Removing the Syringe


Step

Action

    1

Unscrew the plastic plunger holder on the bottom of the syringe (may use pliers).

    2

Unscrew the syringe body from the 4-port valve stand.



Shimadzu Technical Support

...

  • 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


Message

Procedure

Ready

Ready to receive command

Measuring

Measurement proceeding

Waiting for Ready State

Waiting: ready status condition

Washing syringe with acid

Aspirating acid

Injecting acid

Injecting acid

Washing syringe with rinse water

Rinsing syringe

ASI moving

Initializing and checking tray type

ASI pause

ASI pausing

Washing ultra pure water trap

Rinsing ultra pure water trap

Making ultra pure water

Generating ultra pure water

Measuring for blank check

Measuring for blank check

Processing for end of blank check

Processing for end of blank check

Searching for zero point

Searching for syringe home position

Regenerating

Regenerating catalyst

Residue Removal

Removing residue from catalyst

Flow line wash

Rinsing flow lines

Mechanical Check

Mechanical check processing

Monitoring

Background data being sent

Standby

Standby option selected; processing

Shutdown

Shutdown in processing

Initializing

Intializing entire instrument

TOC mech. initializing

Mechanical initializing

Moving

Syringe moving


Analysis Status


Message

Procedure

Sparging

ASI sparging on

Washing

Rinsing sample syringe

Sampling

Aspirating sample into syringe

Injecting

Injecting sample into furnace or reaction vessel

Measuring

Integrating peak profile data

Draining

Draining the sample

Waiting: Interval setting

Waiting for interval setting

Waiting: Ready status

Waiting: ready status is NG (no good)

Waiting: POC

Waiting for POC bubbler

Waiting: ESU

Waiting for ESU

Waiting: Other

Waiting for other

ASI moving

ASI moving

IC regenerating

Automatic regeneration of IC fluid

Bubbling

Bubbling (POC bubbler)


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

Archive Versions

LMUG-TOCUserGuide-230220-1928-172.pdf