Leco CNS-2000 Operation Overview 1 4/4/2018 Operational Overview LECO CNS-2000 Elemental Analyzer
Startup...... 1 Operation...... 2 Diagnostic Checks (optional)...... 2 Pressure/Leak Checks...... 2 Calibration (optional)...... 2 Defining Standards...... 2 Blank Calibration...... 2 Drift Correction...... 2 Full Calibration...... 3 Sample Analysis...... 3 Using Com-Cat/Com-Aid (optional)...... 3 Blanks...... 4 Standards...... 4 Samples...... 4 Result Retrieval (optional)...... 5 Shutdown...... 5 Maintenance...... 6 Changing Reagents...... 6 Anhydrone Tubes...... 6 Reagent Tubes...... 6 Catalyst Heater Tube...... 7 Resetting Counters...... 7 Notes:...... 7
Startup Turn on Oxygen and Helium and the main tank valve. Verify that tank pressure is at least 500 PSI and the regulator flow pressure is 40 PSI. Adjust if needed.
Touch the Analyzer’s screen to display to activate. Touch the Sign On screen key. Enter your major professor’s last name (all lowercase). Touch the Esc screen key, in the upper left corner. Screw the push rod handle into the loading door on the furnace unit.
If you will be using the printer, make sure it is powered-on and online (SEL indicator is illuminated). Leco CNS-2000 Operation Overview 2 4/4/2018 Operation Upon initiation of a new session, you should complete the Leak Check, Blank Calibration and Drift Correction procedures listed below. These need be done only at the beginning of a new session; however you may do them at any time.
A Note on Additives There are some optional additives that may aid in the analysis of your samples. If used, it is usually a good idea to also use the additives in the blanking procedure, to cancel any effects they have on the results.
Tin Boats and Capsules These are used to contain liquid or semi liquid samples which are not suited for direct placement within the ceramic boat.
COM-AID This is a combustion analysis aid in that it helps to hold down light samples (such as dried plant material) and also to contain volatile components that may prematurely escape before complete combustion occurs. It is often used to cover the top of liquid samples. It can be used as top layer over lightweight samples and as a top and bottom layer over volatile samples. Use 1 gram total.
COM-CAT This is a combustion catalyst. It is required for accurate sulfur analysis in plant and soil samples. It may be added to other samples at the operator’s discretion. Use 1 gram to layer over lightweight plant samples or 1 gram mixed into heavier samples and soils.
When any of these additives are used, run boat-blanks, using the listed amount added to the empty boat. For sample runs, enter only the sample weight, not the weight including the additive.
Diagnostic Checks (optional)
Pressure/Leak Checks From the main screen, touch Maintenance then Diagnostics. Touch one of Helium Leak Check, Combustion Leak Check, or Ballast Leak Check. Allow the test to run. Touch Esc to exit or choose next test from the bottom of the screen. Complete any of the above tests desired. If any test fails, consult with the Lab Manager ([email protected]). Touch Esc to exit. Note: After running a Combustion Leak Check, several blanks should be run through the system before any sample analysis, calibration or anything requiring combustion for measurements. Run enough blanks to obtain stable values.
Calibration (optional) Note: Full recalibration should not be required unless you cannot obtain acceptable results from the appropriate standards after Drift Correction (see below). For the following sections, controls are accessed form the main screen by touching Maintenance and then Calibration. Leco CNS-2000 Operation Overview 3 4/4/2018 For all calibration procedures involving sample measurements, refer to the Defining Standards section first.
Defining Standards Follow this procedure if your standard has changed lot numbers (e.g. you open a new bottle). Touch Define Standards. Select the standard of interest from the list, or touch Add Standard to enter another. Verify the lot number and the defined C, N, and S values listed on the bottle as percentages with the standard in the list. If they do not match, touch Modify Standard to enter any required changes. The values set here are used in the calculation of new calibration curves. Touch Esc to exit.
Blank Calibration Note: This procedure should be done at the beginning of each new session and/or when blank results drift from zero. Blanks can be an empty chamber, an empty boat or a boat with the appropriate amount of additive (Com-Cat, Com-Aid, etc.) added. Run a number of blanks (3-5 stable results). Refer to Sample Analysis section for details. From the main calibration screen, touch Blanks. Select the desired elements to include (normally all of them). From the list of results, select the desired entries by touching the Include screen key. Touch Process Results when finished. Accept the changes if correct. Touch Esc to exit.
Drift Correction Note: For most purposes, Drift Correction should be favored over Full Calibration. Run several samples of the appropriate standard (3-5 stable results). Refer to Sample Analysis section for details. From the main calibration screen, touch Drift Correction. Select the desired elements to include (normally all of them). From the list of results, select the desired entries by touching the Include screen key. Touch Process Results when finished. Accept the changes if correct. Touch Esc to exit.
Full Calibration Note: Ideally, full calibration should not be required. Drift correction should compensate for most operating changes. The recommended standard for calibration is Sulfamethazine. If your samples have radically different proportions and/or ranges as compared to the current calibration standard, then you may have to recalibrate using a more appropriate standard to receive consistent results. Try drift correcting with a standard appropriate to your samples. Run additional standards. Look for consistent readings around the expected values. If these work, you may ignore “Out of range” warnings given by the machine. The calibration design should consist of 2 to 3 replicates of 3 to 5 different weight of the desired standard, encompassing your sample weight range. For a sample weight of 0.25 g, the following is recommended:
Standar Standar Standar Weight Weight Weight d d d 0.1-0.15 0.2-0.25 0.3-0.45 R1 R1 R1 g g g Leco CNS-2000 Operation Overview 4 4/4/2018 0.1-0.15 0.2-0.25 0.3-0.45 R2 R2 R2 g g g 0.1-0.15 0.2-0.25 0.3-0.45 R3 R3 R3 g g g
Run the appropriate combination of samples using the desired standard. Refer to Sample Analysis section for details. From the main calibration screen, touch Calibrate. Select the desired elements to include (normally all of them). From the list of results, select the desired entries by touching the Include screen key. Touch Process Results when finished. Statistical data and a curve fit will be displayed. Each element may be accessed by touching the Select Element key. You may accept the presented values or make changes. Changes are only recommended if you know what you are doing. In general, Fit values closer to zero are better. Touch Esc to exit this screen. New and old calibration data will be presented. Accept the changes if correct. Touch Esc to exit.
Sample Analysis Prior to running the first samples of a session (standards or otherwise) in the combustion chamber, you should run several blanks to prime the system. Run enough to produce stable results. The first few will generally be quite variable.
As mentioned above, an analysis session generally begins with the completion of a Blank Calibration and a Drift Correction. This resets the zero point and adjusts the calibration curve for your standard of choice.
Weights may be entered automatically by pressing the Menu key on the balance. The displayed weight will appear on screen, with selected ID code.
Using Com-Cat/Com-Aid (optional) These are additives used to assist in sample combustion. Com-Cat is used for light-weight samples. One gram should be weighed separately and added to your sample material in the boat. For powdery samples (such as plant matter), cover the sample evenly with the Com-Cat. For heavier samples (such as soils), mix the Com-Cat uniformly with your sample. Com-Aid is used for liquid combustion. One gram should be weight separately and added evenly over the top of your sample.
Note: Liquid samples should be contained within a tin liner placed in the boat, rather than in the boat directly. If sulfur in an element of interest, you should use either Com-Cat or Com-Aid in addition to your sample.
Blanks Empty chamber blanks should be run with a base weight of 0.2 g. Boat blanks, if desired should also be run with a base weight of 0.2 g. This is true no matter what else is added to the boat for blank analysis (e.g. COM-CAT, COM-AID, tin liners, etc.). Leco CNS-2000 Operation Overview 5 4/4/2018 See Samples.
Standards Standards should be weighed with a tared boat, and entered into the system. Only the standard weight should be entered. COM-CAT, COM-AID, liners, etc. should not be included in the weight. The standards should be analyzed under the same conditions as your samples, with all additives, etc. See Samples.
Samples Note: If you find it necessary to open the furnace chamber outside of analysis, touch the Furnace Unseal screen key. Touch Seal Furnace to reseal. This is useful when you forget to remove an old sample. All samples are run using an ID code to identify them in the system. You may use an existing ID code if appropriate; however you should use or enter a code representative of your sample and yourself so the result may be identified later. To access the analysis controls, touch Analyze Menu for the main screen. Select the appropriate ID code by touching Select ID Code. Select the code from the list and touch Esc. If required, you may add a new code by touching Add ID Code and entering the relevant information. Make the ID code field something meaningful (e.g. your name ± specific sample information). Touch the OK screen key to save or CANCEL to exit.
Note: If desired, you may make several runs of any standard or other sample to prime the system prior to each set of readings. This may eliminate some variability in the initial readings produced. This is entirely optional. Enter one or more sample weights using the balance or by touching Manual Weight. Using manual weight, enter the weight, touch Enter to add to the list and Esc when done. To delete an entry in the list, touch either Delete Weight to remove the final entry or View Weights to display a list of the weights. Select and delete from the list. Touch Esc to exit.
Touch Analyze to begin analysis. The furnace should unseal and open. Remove any previous samples and load the new sample.
Note: Remove existing boats from the chamber with the hooked rod. Carefully insert the rod, catch the boat and withdraw it slowly. Drop it into the metal bow attached to the front of the loading tray. When the box is cool enough, dump it onto a metal tray and let the boats cool down. Empty cooled boats into the waste containers and place into the used boat box. Follow the on-screen instructions. Do Not use the sample push rod until prompted!
When analysis is complete (approximately 3 to 6 minutes), the unit will beep and the final values for carbon, sulfur and nitrogen will be displayed on the screen. If the printer is online and operational, the results will print as well. All results are stored in the unit and are retrievable. It is best to record your results and your ID codes. Touch Analyze to move to the next sample in the list. Remember to remove the old boat before loading.
Note: You should run one or more standards (with entry of appropriate ID code) after completion of every 10 to 20 analyses. The results from the standard should be used to perform ongoing Drift Corrections. Leco CNS-2000 Operation Overview 6 4/4/2018 If you receive a message about Reagent Tubes, Anhydrone Tubes or Catalyst Heater Tubes needing replaced/exchanged then see the Changing Reagents section under Maintenance.
After the final analysis, touch Unseal Furnace to remove the last boat. Touch Esc to exit.
Result Retrieval (optional) From the main screen, touch Reports.
To view, print or save your results, touch Reports. Scroll through the list, select the results with Include/Exclude Result and/or Database Search. Touch Process Results to choose your action.
Other options are Statistics and Analysis Plot. Touch these options and follow the screen directions.
Touch Esc to exit.
Shutdown Make certain all sample boats have been removed from the furnace chamber. Exit back to the main screen. Touch Log Off. Unscrew the push rod handle and place on counter near furnace unit. Turn off the Oxygen and Helium tanks at their main valves. Do not turn the regulator valves. Record your activities on the machine’s Log Sheet. Leave the machine (main unit and furnace) powered on at all times. Report any problems to the Lab Manager ([email protected]).
Maintenance
Changing Reagents See Resetting Counters when finished changing any of the reagents.
Anhydrone Tubes Pair of tubes on lower front of the furnace unit. Lift each tube upward to disengage lower seal. Tilt tube outward and remove from top seal. Use high temperature vacuum grease to lubricate the upper and lower o-rings that fit into the left tube. Re-insert tube from right into left position. This tube can be reused in this position with out changing the reagents. Twist the tube to set the seal Empty the tube contents into the waste jar. Remove the glass wool from the tube bottom. Rinse tube with de-ionized water and allow to dry. Pack the bottom of the tube with ½” of Glass Wool Fill tube with 4.5” of Anhydrone. Leco CNS-2000 Operation Overview 7 4/4/2018 Use high temperature vacuum grease to lubricate the upper and lower o-rings that fit into the right tube. Re-insert the tube in the right position, top seal first, then lower onto bottom seal. Twist the tube to set the seal. Run some blank samples to prime the system before continuing with measurements.
Reagent Tubes Pair of tubes on upper left of main display unit.
Lift each tube upward to disengage lower seal. Tilt tube outward and remove from top seal. Remove glass wool from tube top. Empty tube contents into waste jar. Remove remaining glass wool from tube bottom. If screen filter in tube bottom is dirty, clean in an ultrasonic water bath.
Rinse tube with de-ionized water and allow to dry.
Repack tube as follows: Screen filter inserted into bottom. Next, 0.75” of Glass Wool, loosely packed. Fill bottom 1/3 of main body with Anhydrone. Fill top 2/3 of main body with Lecosorb. Finally, 0.75” of Glass Wool, loosely packed.
Note: Keep all strands of glass out of the neck of the tube. They can cause leaks in the o-ring seal. Use high temperature vacuum grease to lubricate the upper and lower o-rings that fit into the tube ends. Re-insert the tube, top seal first, then lower onto bottom seal. Twist the tube to set the seal. Run some blank samples to prime the system before continuing with measurements.
Catalyst Heater Tube Note: Be careful! This tube is hot. Tall tube on lower left of main display unit. Passes through a rectangular heating chamber. Loosen screw on top of retaining block (holding top of tube). Remove tube from chamber. Empty contents of tube into waste jar.
Note: The contents tend to be congealed. You may wish to repack a different, empty tube and deal with emptying this one when it is cool.. When cool, empty tube should be rinsed with de-ionized water and allowed to dry.
Re-pack the tube as follows: Bottom 1” of main body (above the reduced tail) filled with Copper Turnings. Next, 1.75” filled with N-Catalyst. Next, 0.25” filled with Copper Turnings. Next, 7.25” filled with Copper Sticks. Leave an empty space (1” to 1.5”) at top. Leco CNS-2000 Operation Overview 8 4/4/2018 Use high temperature vacuum grease to lubricate the upper and lower o-rings that fit into the tube ends. Insert the tub into the chamber and engage the lower o-ring. Allow the tube to heat up. Wait until moisture no longer condenses around the top of the tube. Insert the top o-ring into the tube and tighten the retaining block. Run some blank samples to prime the system before continuing with measurements.
Resetting Counters Touch Esc until the Front Panel is displayed (title at screen top reads “Front Panel”). Touch Modify Counters at the bottom of the screen. Touch the arrows at the bottom of the screen to select the counter. Touch Reset Counter to reset the counter. Only reset the counters for which you have changed the reagents! Touch Esc to exit. Notes: