The Quick-Start Guide to the
Chemical Analysis Instruments at
Grand Rapids Community College
2nd Edition
By
Jennifer Batten
Tom Neils
Bernard Liburd
andBill Faber
Table of Contents
Nuclear Magnetic Resonance (NMR)Page
Anasazi NMR…………………………..…………………………………………………….. 2
Infrared (IR) Spectroscopy
Jasco IR…………………………………………………………………………………….……4
Gas Chromatography (GC)
Agilent GC………………..…………………………………………………..……………….5
Gas Chromatography/ Mass Spectrometry (GC-MS)
Agilent GC/MS………………………………………………………………………….…… 7
High-Performance Liquid Chromatography (HPLC)
Buck HPLC…………………………………………………………………………………….10
Hitachi GPC………………………………………………………………………..………..12
Hitachi HPLC…………………………………………………………………………………14
UV-vis Spectroscopy
Lambda 20 UV-vis…………………………………………………………………….….16
Ocean Optics UV-vis…………………………………………………………..………..17
Spec 20………………………………………………………………………………………..19
Karl Fisher Titrators
Model 701……………………………………………………………………………………20
Model 758…………………………………………………………………………………...21
Differential Scanning Calorimetry
Mettler Toledo DSC 821e…………………………………………………………..…23
Graphite Furnaceand Atomic Absorption Spectroscopy (AAS)
Varian AAS…………………………………………………………………………………………...25
Aurora Instruments………………………………………………………………….…….…….27
The instruments included in this manual have far more capabilities than described in this guide, which is intended to get you started on sample and data analysis. Please enjoy your chemical analysis and have fun learning and seeing what these instruments can do!
Nuclear Magnetic Resonance (NMR)
Anasazi NMR
Set- up
1. The password for this instrument is Anasazi.
2. Turn on pump that supplies air to the NMR by turning on the surge protector that it is on the floor next to the magnet. Turn on the computer monitor and restart the computer if it is not already on. Prepare a 1mL sample that is about 5% ethylbenzene, 1 % TMS and the remainder chloroform-D(this sample is usually prepared and is the one with the blue NMR tube cap). Add this sample to an NMR tube and wipe the tube clean with a Kim-wipe. Put the NMR tube into the spinner. Remember that the wider end of the spinner goes up. Use the guide to correctly position the spinner on the NMR tube. To put the sample with the spinner into the NMR, flip the black lever on the NMR up to turn off the air. Drop the NMR tube with spinner into the instrument. Turn the air back on by putting the black lever back down. Use the flashlight to look inside the NMR to make sure the sample is spinning. If it is not, remove the sample by putting your hand over the sample hole to catch the sample as it exits and pushing the black button next to the black lever to eject the sample. Repeat the steps to put the sample in the instrument.
3. On the computer, click on the aii tab and then type shim. The computer will ask for a relaxation delay, type 5. Wait until the instrument is done shimming (about 5 minutes). Then set the TMS peak to zero by first typing ZG and press theEnter keytwice. Wait until the data is collected as evident by a yellow (or red-sample to concentrated) line on the monitor screen. Click on NMR and hold down the a key and then type 2. Use the mouse to drag the vertical line to the TMS peak (the one most to the right) and note the position of the peak in units of ppm (lower right corner). Click on aii and type fo. The computer will ask for the current position of the TMS peak, carefully enter the correct value including a – (negative) if necessary and hit the Enter key. When the computer asks for the desired position, type 0 (zero)and Enter. Remove the ethylbenzene sample from the NMR as described in the first step.
Data Collection
1. Wipe the NMR tube with a Kim-wipe. Put the NMR in the spinner as shown by your instructor. Remember that the wider end of the spinner goes up. Use the guide to correctly position the spinner on the NMR tube.
2. Flip the black lever on the NMR up to turn off the air. Drop the NMR tube with spinner into the instrument. Turn the air back on by putting the black lever back down. Use the flashlight to look inside the NMR to make sure the sample is spinning. If it is not, remove the sample by putting your hand over the sample hole to catch the sample as it exits and pushing the black button next to the black lever to eject the sample. Repeat the steps to put the sample in the instrument.
3. Once the sample is spinning, go to the computer. If the screen is not on the blue aiiscreen,click the tab that says aii at the bottom of the screen. Type zgand hit the Enterkeytwice. Your spectrum is now being collected. When a yellow (or red) line appears, your data collection is complete your sample can be removed so that the next person can put their sample into the NMR (step 2).
4. To work up your data, click on the NMR tab at the bottom of the screen. Hold downCtrl and press F2. Click on open thenOK. Type fb. Make sure the baseline (no peaks) is covered with red lines. The red lines can be turned on or off by clicking on them with the mouse. Then type L(lower case) and hit the Enter key. You can use the side bar on the right side of the screen to increase or decrease the size of your peaks. Type id to display the integrals. You may make the integrals larger or smaller by moving the side bar on the left side of the screen. Go to File and then Print.
5. If you have not already done so, remove you sample as described in step 2.
6. Pour your sample into the halogenated waste bottle. Rinse the NMR tube with acetone and put it on the instructor’s desk.
Shut Down
When the sample analysis is complete, turn off the air pump and the computer monitor. Please leave the computer on.
Infrared Spectroscopy
Jasco IR
Set-up
Turn on the IR and wait until you hear 3 short beeps. Then turn on the computer and monitor. Open Spectra Manager by clicking on the icon. Then open Spectra Measurement, so that data can be collected, and Spectra Analysis, so that the data can be worked up, by clicking on these items.
Data Collection
1. Bring the Spectra Measurementwindow forward by clicking on it. Make sure the sample compartment is empty and clean. If it is not, use methanol and soft toilet paper to clean the crystal and the metal upper part of the sample holder. You may find it necessary to flush the chamber with nitrogen gas to remove any residual solvent vapors. Next collect a background spectrum by clicking on B (Monitor Background). If that background spectrum is satisfactory, click OK. If you selected Background instead of Monitor Background, you will not need to click OK.
2. To collect a sample spectrum, cover the crystal with sample. Be careful not to touch the crystal with any sharp object like a spatula as it is easily scratched and is very expensive. Close the sample compartment by pushing the lever in the left side of the dial toward the dial and then move the dial forward. Rotate the dial clockwise until it comes to a natural stopping point (do not force).
3. After the sample has been added, click on S (Monitor Sampleor Sample Measurement). If the spectrum is not what you expected, it is most likely that the sample compartment was not clean when the background was collected. If the spectrum is acceptable (or not) click OK. Go to File and select Analysis Send. Wait until the spectrum appears in the Spectra Measurement window.
4. Bring the Spectra Analysis window forward by clicking on the screen. To remove the CO2 peak, click on the No CO2 tab. In the range box area select the 2200-2400 cm-1 region and then OK. To number the peaks, click on the Peak Find icon (it looks like two black peaks with yellow tops). If not on already, check the upper and lower limit boxes. Two lines should spear on the spectrum. The lower limit line may be at the very bottom of the screen. Move the lines up or down by clicking and dragging them. Any peak that is between these lines will be labeled. When the numbering is satisfactory, click Apply and then OK. To print the spectrum, go to File and then Print.
5. Clean the sample compartment by first unscrewing the dial in a counter clockwise direction and then pressing the lever toward the dial and pushing it backwards. Then clean the crystal with methanol and soft toilet paper.
Shut Down
Please turn off the IR and shutdown the computer when data collection is finished. Make sure the sample compartment is clean.
Gas Chromatography (GC)
Agilent GC
Set-up
1. Do not adjust the pressure control valves on the gas tanks connected to the GCs. Open the valves on top of the cylinders for the gasses (helium, air and hydrogen) that are connected to the gas chromatograph (GC). If you plan to use the 6890, open the second set of valves that are inline to this instrument. If you do not plan on using the 6890, please close these valves to save gas. Turn on the GC and then the computer. There is no password, so clickEnter when this screen opens. Open the GC software by either clicking on the Instrument 1 onlineicon or by going to Start, then Programs, Chemstations, and Instrument 1 Online.
2. Once the software has opened, parameters can be set by going to the Instrument drop down menu and then selecting Quick Setupon the 6850 or Edit Parameters on the 6890. The parameters you may want to change are outline below:
Inlet- The split ratio is the amount of injected material that enters the column versus what portion is sent to the split vent. For example a 1:100 split ratio means that 1 part injected material enters the column while 99 parts is sent to waste. If your column appears overloaded, as evident by broad peaks, a higher split ratio may fix this problem. Another important parameter is the injection port temperature. The instrument is usually set to 300°C. The higher temperature means that more of the material immediately enters the vapor phase when injected, which leads to narrow peaks. If this temperature is set too high for an application, the analytes can decompose in the injection port.
Column- In this section the length, diameters and type of column in entered. This information should not need to be changed unless a new column is installed.
Oven-Under Oven, temperature of the oven and any ramp times are set. A good rule when setting the first set of conditions for a separation is to set the oven 10°C less than the boiling point of the lowest boiling point compound. The higher the oven temperature, the faster the analytes will elute from the column and the narrower the peaks will be, but the resolution of the peaks will be lost if the oven is too hot. Excessive heat can damage a column; each column has a maximum temperature (usually 250-300°C) that should never be exceeded. If your temperature does not change during a separation, be sure set a run time.
Detector-Under detector, the temperature of the FID detector can be set. The default is 250°C, which is fine for most applications. Excessive heat will reduce the lifespan of the detector.
If you change any parameter, you may click on the Apply tab. When, you are finished making changes, click on OK.
Making an Injection and Data Collection
1. Wait until the Green Ready signal appears in the upper left corner of the screen.
2. To prepare the sample for injection, first rinse the syringe with three small portions of your sample. Then load 0.5 – 1 micro liters of sample into the syringe. Then pull the syringe plunger back to add a 1 micro liter plug of air.
If you will use the data to find the percent of 2 or more components in a mixture or to simply determine sample purity, exact injection volumes or small air bubbles will not be an issue. However, if you plan to use the data to determine the concentration of an analyte in a mixture, it is highly recommended that you use the internal standard method for calibration as small injection errors can greatly influence results.
3. Guide the fragile syringe into the (hot) injection port. The syringe needle should be at least 2/3 down into the injection port. If there are two injection ports, use the back injection port for most applications. Gently but firmly, tap the plunger and then press the Start button on the GC. This action will begin data collection. Remove the syringe from the GC.
4. The run time can be viewed on the computer. Data collection can be stopped at any time by either clicking on the Stop tab or by going to the Run Control drop down menu and selecting Stop Run. When data collection is complete, either through a manual stop run or when the preset run time is complete, a report will be generated. Inspect the report and if it is satisfactory, click on the Print tab on the report.
The most common problem with GC data is split peaks; this problem is due to hesitation while making an injection. To fix this problem, the sample analysis must be repeated with better injection technique.
5. The next injection can be made when the Ready is again green.
Shutdown
When GC analysis is complete, to prevent column damage the oven must be cooled before the carrier gas is turned off. Go to the Instrument dropdown menu to Quicksetupand under Oven, change the temperature to 40°C and click on Apply. When the oven has cooled, the software can be closed. It is not necessary to save your methods. The Cag bootpmay need to be shut down as well (see bottom bar for tab on the 6850) before shutting down the computer and then the instrument. Remember to turn off the gases by closing all of the valves. Clean the syringes with acetone or an alcohol.
Gas Chromatography-Mass Spectrometry
Agilent GC-MS
Set-up
1. The user name for this instrument is GRCC and the password is sweetbaby.
2. If using the autosampler (ALS), make sure that the plunger on the syringe operates smoothly. If not, remove the syringe and clean or replace it. Check to ensure that the syringe wash vials are full. Place acetone into wash position 1 and hexane into wash position 2. Make sure that there is a waste vial in place. Do not fill vials on top of the instrument as the plastic can be damaged with certain solvents.
3. Select the Sweetbaby Icon (if already running, it can be opened from the bottom of the screen). The instrument will most likely be in STANDBY Mode. Load the method of your choice by selecting Method and then Load Method. If you plan to create a new method, select any method other than STANDBY to start method development. If your method is already prepared, go on to the Data Collection section of these directions.
4. To edit an existing method, go to Methodand then select Edit Entire Method. A dialog Box called Edit Method should appear. Ensure that all 3 boxes are selected & click OK. Under Inlet and Injection Parameters select either Manual or GCALS (for the autosampler) and Apply or OK. The next important area to edit is the GC Edit Parameters dialog box. Some parameters that should be set are:
- ALS: Set the syringe cleaning and sampling technique in this dialog box. Two washes with each solvent before and after analysis should be sufficient. Wash the syringe with sample at least 2 times.
- Ovens: Set your GC Parametersbased on your sample mixture. Make sure that the oven box is checked so that the oven is turned on. Check your run time to make sure that it is appropriate for your sample.
- Inlets:Set the split ratios. A 1:400 ratio means less compound enters the column than a 1:10 ratio.
- Select OK when finished
5. On the next 2 dialog boxes, click “OK.”
6. In the dialog box “MS SIM/Scan Parameters” set the following:
Solvent delay: Set the time here so that the MS part of instrument turns on after the solvent has passed through. This time is usually 1-2 minutes.
Scan Parameters: Set the following Mass Spectrometer parameters
- Starting Mass: 35.00amu (This avoids detection of water, N2 and O2.)
- End Mass: Select a mass to cover the range of the compounds to be analyzed.
- Click Close and click OK.
7. Under Dialog box Select Reports