Topics discussed below:

• Basic principle of water analyses
• Multiflow set:up 
• Sample preparation
• Oxygen isotope analyses
• Hydrogen isotope analyses
• Dissolved inorganic carbon (DIC) analyses
• Calibrating inhouse standards and CO2 reference gas
• Clean-up

Basic principles:

1. I

Multiflow set-up:

1.  Open the red-handled valve to the pressurized line behind the Multiflow.  (Assuming that the green valve is already opened on the line and the air pressure is set to 70 psi).
 

2.  Make sure the power plug and computer plug are properly plugged into the back of the Multiflow unit.  Turn on the black switch that is located just above the power plug (by depressing the top half of switch).

3. Make sure He cylinder in other room is open and that the pressure on the gauge farthest from the cylinder is set at 400 kPa. Turn on the furnaces for the 4-way and 6-way valves (VW and VV valves, respectively) and the GC column in the Multiflow unit.
 

4. Turn up the gas flow through the Reference gas side of the TCD (at the end of the GC Column) so that 15 ml/min of He is flowing thru the vent on top of the Gilson unit.  Need to have the VU valve set so that the green box on the computer screen is down (closed).  Check the flow rate by putting the bottom of the Gilman flow meter gently into the black cylinder.  Be gentle with the end of the flow meter when you attach and detach it to/from the black cylinder.  The end comes off easily.  If it comes off, the ball will fall out.
 

5. Turn up the gas flow through the GC Column so that 15 ml/min of He is flowing thru the tent on top of the Gilson unit.  Need to have the VU valve set so that the green box on the computer screen is up (open).  At the time of installation of the machine, the value on the gauge was 19.1; this valuee will vary slightly.
 

6. Turn the black-handled valve behind the Gilson unit so that it is parallel to thesteel line (pointing toward the red-handled valve).  This will let in the CO2-He mixture from the tank in the other room.  (Make sure the black-handled valve in the other room is turned toward the CO2-He tank and not the H2-He tank.) Turn up the gas flow through the sample vessel so that 40? ml/min of CO2-He is flowing thru the needle.  Check  the flow rate by 
 

7. The flush of the needle .......
 

8. Make sure the needle assembly is set up for water analyses.
 

9. Make sure the needle will properly locate itself relative to the sample tray by initializing the Gilson unit (i.e., the unit that controls the needle).  You must check this visually by doing the following commands on the computer.... (INLET => INITIALIZE GILSON (moves needle up and down) => PROGRAM => RUN => type in 1,1,1 into the Parameter line => double click on GMOVE.  The needle will move the 1st rack and position itself over X=1, Y=1 sample position.  If you forgot to input the parameters, you will get an error message for lines 55, 56, and 57 in the GMOVE.seq file.

Move the needle down close to the top of the sample vessel by using the GDOWN command.  First go to ANALYSIS => PARAMETER FILE EDIT => HEATED SAMPLE TRAY, 1/10 mm => EDIT => NEEDLE DOWN POSITION => input 760 (which will move the needle down 1.5 cm from its "up" or rest position) => OK.  Then go to.... PROGRAM => RUN => GDOWN ... and the needle will move down.  If the needle appears to be centered on the sample hole, then change the needle down position to 860 and then do another GDOWN command.... Repeat the process of changing the needle down position until you reach 1110. 

Then MAKE SURE to lift the needle back up by going to  ... PROGRAM => RUN => GUP.

10. Turn on the heater to the sample tray by plugging in the plug on the back of the tray.  The temperature of the tray should be set to 40 C. To check this, push the green button on the left side of the Sample Temperature gauge and the temperature set point will be displayed.  This is the temperature to which the heat will obtain when it reaches equilibrium.  If the set point is not 40 C, then hold down the green button on the left and then scroll up or down with the two green buttons on the right.
 

Sample preparation:

1.  For OXYGEN analysis, pipette 200 microliters of water into a reaction vessel and then immediately screw on the lid in order to minimize the loss of water by evaporation. Please be careful with the pipette -- such pipettes are easy to break.  Gently put the tip on, but be careful to just hold on to the broader end of the tip rather than at the point (in order to avoid any contamination of the sample).  To get the tip off the pipetter, push gently the green bar down toward the tip.  This will push off the tip.  DO NOT PULL THE TIP OFF WITH YOUR HAND.
 

movie

For HYDROGEN analysis, pipette 200 microliters of water into vessel, add a coil of Hokko beads with tweezers, and then immediately screw on a lid.  DO NOT touch the Hokko coil or beads with your fingers in order to not contaminate them!  Please be careful with the pipette -- such pipettes are easy to break.  Gently put the tip on, but be careful to just hold on to the broader end of the tip rather than at the point (in order to avoid any contamination of the sample).  To get the tip off the pipetter, push gently the green bar down toward the tip.  This will push off the tip.  DO NOT PULL THE TIP OFF WITH YOUR HAND.
 

movie

For both oxygen and hydrogen analyses, you need to analyze standard waters in addition to your samples.  The primary inhouse standard is known as  SLU TAP H2O.  There is 10 liter bottle of this standard and numerous smaller aliquots of this standard in glass bottles.  Use these glass bottles for day-to-day use.  There are several other inhouse water standards that you can use periodically.  The isotopic values of these inhouse standards have been calibrated to VSMOW and GISP standards.
 

2.  Load your samples in the metal sample tray on the Multiflow unit.

The X-direction of the tray (notation in computer program) is parallel to the long dimension of the tray (<------>).  The Y-direction is parallel to the short dimension.

3.  Place the metal cover over the top of the samples and gently lower down until it rests again the metal sample holder.  You might have to gently rock the cover in order to get all the sample caps aligned with the holes in the cover.  Then remove the black-handled screws, and then put on the foam and metal covers (though the covers are not necessary).  The covers are designed to insure uniform temperature among the samples.
 

CO2Oxygen isotope analyses:

1.  On the computer, go to ANALYSIS => PARAMETER FILE EDIT => MULTIFLOW PARAMETER FILE => EDIT PARAMETER window.  Input your desired parameters and then save the settings.  For example, .....
 

1st sample rack number	1	Is always set to 1
1st sample X position	1	is 1 if sample is in top-left corner of sample tray
1st sample Y position	1	is 1 if sample is in top-left corner of sample tray
Automatically Fill Vials	TRUE	alternatively, can be FALSE
Number of Vials to Fill	33	for example 33 vials; DO NOT exceed 60!
Vial flush time (seconds)	360	for example 360 secs flush of vials
Sample equil. time (mins)	270	for example 270 minutes (4.5 hours); this value can vary as long as all samples have at least 4.5 hours to equilibrate with the CO2 in the CO2-He mixture; use Excel program entitled "Calculate Runtimes" to calculate total equilibration and total run times.

Then hit OK to exit the parameter file.

2.  Go to ANALYSIS => METHOD SETUP => LOAD => CO2MULT (in comment line).  Go to SEQUENCE and make sure the START SEQUENCE is CSTART and the END SEQUENCE is GILEND.  Then click OK => OK (SAVE).

3.  Go to... ANALYSIS => EDIT AUTORUN => NEW => input a filename that contains 8 characters or less => OK => 
 

set Procedure to DEFAULT 
Rack Type to Heated_R 
check mark AutoRea

then for each sample
Type is Sam
Pos (stands for Rack #, X, Y position for each sample)
Name (give the sample's name)
Method is CO2MULT
(If you want to provide an ID, then check mark ID box and then add text)

Then CLOSE the AutoRun Batch window.  DO NOT Run the analysis at this time unless you know that all the gases are flowing properly through the Multiflow and Isoprime.
 

4.  Open the valve on the CO2-He mixture tank cylinder in room 232A and make sure there is pressure recorded on both gauges.  The second gauge should record 60 psi (400 kPa).
 

picutre of gauges

close-up of gauges

5.  Turn the black Whitey valve on the stainless steel line behind the Multiflow unit to CO2-He mixture.
 

6.  Can check to make sure that enough CO2-He gas (for flushing the vessel and equilibrating the CO2 gas with the water) will flow through the needle by attaching the soap-filled glass and plastic tubing to the end of the needle.  Insert the needle through the septum in the plastic tubing, put some Snoop soap into the glass tubing, compress the bottom of the plastic tubing to spread the soap across the tube, and the monitor the flow rate of the CO2-He mixture.  The "VT" valve on the computer monitor must be open for the CO2-He mixture to flow through the needle.  The black-knobbed valve on the back of the Multiflow controls the flow rate of the CO2-He mixture through the needle.  The flow rate should be 40 ml/minute.

7.  Can check to make sure that enough He gas (for pressurizing the vessel after equlibration) will flow through the needle by attaching the soap-filled glass and plastic tubing to the end of the needle.  Insert the needle through the septum in the plastic tubing, put some Snoop soap into the glass tubing, compress the bottom of the plastic tubing to spread the soap across the tube, and the monitor the flow rate.  The "VB" valve on the computer monitor must be open for the He to flow through the needle.  The "Sample Vessel" valve on the front of the Multiflow controls the flow rate of the He through the needle.  Set this to be 2.9 psi.
 

8. Go to ... ANALYSIS => EDIT AUTORUN => PREPARED => locate your batch file and double click => RUN.  The computer will then take over and do the analyses.  You can CLOSE the Auton Batch window.

Hydrogen isotope analyses:

1.  On the computer, go to ANALYSIS => PARAMETER FILE EDIT => MULTIFLOW PARAMETER FILE => EDIT PARAMETER window.  Input your desired parameters and then save the settings.  For example, .....
 

1st sample rack number	1	Is always set to 1
1st sample X position	1	is 1 if sample is in top-left corner of sample tray
1st sample Y position	1	is 1 if sample is in top-left corner of sample tray
Automatically Fill Vials	TRUE	alternatively, can be FALSE
Number of Vials to Fill	33	for example 33 vials; DO NOT exceed 60!
Vial flush time (seconds)	360	for example 360 secs flush of vials
Sample equil. time (mins)	90	for example 90 minutes (1.5 hours); this value can vary as long as all samples have at least 90 minutes to equilibrate with the H2 in the H2-He mixture; use Excel program entitled "Calculate Runtimes" in order to calculate the total equilibration and total run times.

2.  Go to ANALYSIS => METHOD SETUP => LOAD => H2MULT (in comment line) => OK (SAVE)

3.  If you have more than one sample to analyze, then go to... ANALYSIS => EDIT AUTORUN => NEW => input a filename that contains 8 characters or less => OK => 
 

set Procedure to DEFAULT 
Rack Type to Heated_R 
check mark AutoRea

then for each sample
Type is Sam
Pos (stands for Rack #, X, Y position for each sample)
Name (give the sample's name)
Method is H2MULT
(If you want to provide an ID, then check mark ID box and then add text)

Then CLOSE the AutoRun Batch window.  DO NOT Run the analysis at this time unless you know that all the gases are flowing properly through the Multiflow and Isoprime.
 

4.  Open the valve on the H2-He mixture tank cylinder and make sure there is pressure recorded on both gauges.  The second gauge should record 60 psi (400 kPa). 

5. Check the TCD is set at 100 and a zero of 0.5

6.  Turn the valve on stainless steel line behind the Multiflow unit to H2-He mixture.
 

7.  Can check to make sure that enough H2-He gas (for flushing the vessel and equilibrating the H2 gas with the water) will flow through the needle by attaching the soap-filled glass and plastic tubing to the end of the needle.  Insert the needle through the septum in the plastic tubing, put some Snoop soap into the glass tubing, compress the bottom of the plastic tubing to spread the soap across the tube, and the monitor the flow rate of the H2-He mixture.  The "VT" valve on the computer monitor must be open for the H2-He mixture to flow through the needle.  The black-knobbed valve on the back of the Multiflow controls the flow rate of the H2-He mixture through the needle.  The flow rate should be 40 ml/minute.

8.  Can check to make sure that enough He gas (for pressurizing the vessel after equlibration) will flow through the needle by attaching the soap-filled glass and plastic tubing to the end of the needle.  Insert the needle through the septum in the plastic tubing, put some Snoop soap into the glass tubing, compress the bottom of the plastic tubing to spread the soap across the tube, and the monitor the flow rate.  The "VB" valve on the computer monitor must be open for the He to flow through the needle.  The "Sample Vessel" valve on the front of the Multiflow controls the flow rate of the He through the needle.  Set this to be 2.9 psi.
 

9.  Make sure the Isoprime is set up to do hydrogen analyses.  Do the following steps. 

"Center H" scan, an H3 calibration, and an H2 stability.

10. Go to ... ANALYSIS => EDIT AUTORUN => PREPARED => locate your batch file and double click => RUN.  The computer will then take over and do the analyses.

Dissolved inorganic carbon analyses:

Multiflow
* Before switching or disconnecting the gases make sure of the correct parameters.
* If switching or disconnecting the He carrier make sure the TCD, valves and oven are all switched "off."
* If switching or disconnecting the flushing gases always recheck needle flow rate via opening "VT" (40 ml/min).
* If switching sample loop length always close "VV" so as not to leave the column open.

Sample Vessel Pressure
* Can be adjusted via the regulator next to the gauge.  To check the true reading toggle "VB" should measure about 3 psi.  Increase the sample pressure increases sensitivity, and vice versa.

Acid Delivery
* Purge the acid line with water, but disconnect for the silica and needle.  Run sequence program called Piptest via program ? run ? piptest or via opening "VX."

 Dic.  Page 125  (multiflow)
* The only thing not noted is the changing of sample loop size.  Normally the loop size 50 ml = 11.5 cm with Dic this is increased to 200 ml = 46 cm.
* The loop is located on the six way valve.

(add drawing here)
 

* A = sample He
* B = one end of sample loop
* Vent—this is where you can measure the "column" and "Ref. He" flow rates that can be adjusted on the front of the multiflow.
The flow rate should be 20 ml/min.
Switching between the two is done by toggling VU (never have the TCD on without gas flow).
* D = ST/ST line connecting out the front of the multiflow to the needle.
* E = one end of sample loop.
* F = sample in—sample to the column.
 

Using Different Racks
1. Check analysis—parameter edit file.
2. Edit parameter files—will appear.
3. Select—current rack parameters (click Edit).
4. Edit parameters—use rack file:  Heated_R
5. Use the heated sample tray and its parameter saved in (heated sample tray, 1/10 mm)
6. To change this go to analysis—Edit autorun.
7. Depending on which file you are selecting—New Prepared Run (Enter).
8. Autorun batch: ???  (file name).
9. Rack type:  Heated_R—click on this box.
10. Heated_R—Edit: select scroll and all the other rack names are there to select.
 

Clean-up:

Calibrating reference gases after changing the tanks:

1.  A new tank of CO2 Reference Gas:  Go to ... ANALYSIS => METHOD SETUP => CO2MULT => SPECIES => choose CO2=> EDIT.  Put in zeros for the values of carbon and oxygen.  Then run a series of carbonate standards with a wide range of isotopic values.  Plot the results such that the measured values are on the X-axis and the accepted isotopic values are on the Y-axis.  The slope of the regression line should be 1.000.  The Y-intercept is the isotopic value of the CO2 reference gas in the tank.  This value needs to be inputted into the computer program.  Go back to ... ANALYSIS => METHOD SETUP => CO2MULT => SPECIES => choose CO2=> EDIT => and input the isotopic values into the boxes.  These values are relative to    next to "With Respect To" choose PDB => OK.

2.  A new tank of H2 Reference Gas:  The OS2 software does not handle hydrogen analyses in the same way it does the CO2.  Consequently, you must use the H2Utils software for putting inthe reference gas isotopic values etc.  Startup the h2utils program by double clicking the icon on the computer screen.  Go to ... FILE => PARAMETERS => REFERENCE DETAILS => LABORAROTY REFERENCE GAS box and input zero into the Enrichment (per mil) box and make it with respect to SMOW.  Click OK and then run a series of water standards for hydrogen.  Plot the results such that the measured values are on the X-axis and the accepted isotopic values are on the Y-axis.  The slope of the regression line should be 1.000.  The Y-intercept is the isotopic value of the H2 reference gas in the tank.  Go back to h2utils program FILE => PARAMETERS => REFERENCE DETAILS => LABORAROTY REFERENCE GAS box and input the value into the Enrichment (per mil) box and make it with respect to SMOW.  Also input the values you obtained for VSMOW and SLAP.  The program will then give you the "stretch factor". This value will be printed out with the results of each future analysis.  Click OK and the results provided by the computer should now be corrected properly for the reference gas.