Microwave Digester #1 General Process Description Standard Operating Procedure (SOP) This instrument is used to digest small amounts of material for chemical analysis (ICP), by placing the sample in a Teflon crucible adding acid, and microwaving the sample for a certain amount of time. All work described in this SOP will have to be conducted in room JHE 240 in the fume hood. You MUST have WHMIS Training before working with any acid. Contact Person is Ed McCaffery Laboratory Manager (Room JHE 248 ext 24985). #2 Hazardous Chemicals/Class of Hazardous Chemicals The microwave digester uses concentrated acids including hydrofluoric acid which are very corrosive and dangerous. Some acids are also shock sensitive which given the right conditions can explode. Concentrated acids may be fatal if inhaled; can cause severe eye and skin burns, severe respiratory and digestive tract burns. Contact with other material may cause a fire. Whenever working with concentrated acids it MUST be done in the fume hood. Some frequently used acids for Microwave digestion: (~65%) Nitric acid (HNO 3 ) (~32%) Hydrochloric Acid (HCl) (~96%) Sulphuric Acid (H 2 SO 4 ) (~97%) Phosphoric Acid (H 3 PO 4 ) (~48%) Hydrofluoric Acid (HF) These are not the only acids used just some of the more common used in the microwave digester. #3 Personal Protective Equipment (PPE) Before any acid is taken out of the acid-storage cabinets, ensure that you will at least meet the following protective requirements: 1. Goggles (prescription glasses are not enough!) Must seal around glasses 2. Gloves preferably nitrile 3. Closed-toe shoes with socks 4. Long pants (no shorts!) 5. Face shield if not wearing goggles 6. Neoprene apron or Lab Coat 7. Know where the Chemical Spill Kit is located. 8. No contact lenses
Before proceeding, you must have read and are familiar with the MSDS for each of the hazardous materials you will be using. All Material Safety Data Sheets (MSDS) are located in room JHE 248 top shelf East Wall. Ensure the spill kit is available in the event of an exposure. The acid spill kit is located underneath the paper dispenser in room JHE-240. If you spill Hydrofluoric acid DO NOT use the acid spill kits use the HF spill kit located in the same room. #4 Engineering / Ventilation Controls All work with concentrated acids must be done in the fume hood, with no other persons working close enough to interfere or come into contact with the acid; someone must be in the immediate area in case of an emergency, the fume hood protective shield drawn down as much as possible, but allowing to work comfortable. Make sure when you are dispensing the acids that the bottle being dispensed in is far enough in the fume hood so that fumes will not come back to the users face. #5 Special Handling Procedures and Storage Requirements Place a secondary containment tray in the fume hood, when handling and pouring concentrated acids. In case you overfill or spill acids, it will stay in this secondary containment. Remember to slowly pour acid into water, never water into acid. No rinse water with ph below 5.5 may be drain disposed.
Please review the last page for emergency contact and notifications. #6 Spill and Accident Procedures If you spill acid and the spill is an immediate threat to your health, leave the room, call 88. Remain nearby. In the event of an acid exposure, follow McMaster University First Aid Instructions posted in the labs. If you accidentally spilled concentrated acid (e.g., while pouring an acid into the measuring cylinder): Don t panic! Remain calm. If the spill is minor (less than 30mL, note a 5 inch x 7 inch paper towel will absorb 5 ml of water ), and will not pose a health issue; use the spill-containment kit; pour the absorbent; first make a circle encompassing the spill then pour the absorbent on top of the spill. Find a plastic/neoprene-disposal bottle in room JHE 248 and carefully place the soaked absorbent into the bottle, and place in Chemical Waste label on the container. To minimize contact with the acid during clean-up, use the small broom and dust pan to move the soaked absorbent into the bottle. All of this must be done in the fume hood. If the spill is significant; larger (> 30 ml) or you flipped over an entire bottle of acid, if the spill does not pose a health hazard; inform any other personal in the lab; then use the spill-containment kit in room JHE 240 underneath paper towel dispenser. Pour the absorbent around the spill then pour the absorbent all over the spill. If spill is greater than 30 ml, or cleanup takes longer than 15 minutes, document the cleanup activity either by calling EOHSS at Ext 24352 or by notating the lab inspection forms. IF THE CONCENTRATED ACID IS RUNNING OUT OF THE FUMEHOOD, place spill-containment absorbent on the spill and contact EOHSS at 24352 or call 88 (Emergency) immediately and leave the laboratory making sure you notify any personal in that lab, but stay nearby to provide information to responders. DO NOT TRY to place the soaked absorbent into the neoprene bottle, as fume evaporating from the concentrated acids pose a serious health hazard. Contact Emergency Response (88), Ed McCaffery Ext 24895 and Lisa Morine Ext 23314. If the spill runs underneath the fume hood, lab equipment or if it goes down sink call EOHSS Ext 24967. If a fire breaks out because of the acid spill leave the area immediately, activate the fire alarm, and call 88. Stay close to the building to inform emergency personal of what started the fire and what other chemicals are in the immediate area of the fire (note on this web page is a chemical list of all chemicals in the Materials Science & Engineering Department).
#7 Waste Disposal If you ve spilled acid and soaked up acid using absorbent, make sure it is disposed into neoprene bottle (4L). These containers will be labeled with a Chemical Waste Label. Any waste acids are to be dispensed in the Chemical Waste Buckets located in the fume hoods. Any glassware used needs to be rinsed three times prior to washing. #8 Training requirements Although this SOP contains a detailed operating procedure the user MUST be fully trained by a qualified technical staff member. Prior to entering and working in the laboratory, you must have completed WHMIS training; you are required to also take Specific Workplace Training through EOHSS. You must have written and have signed the safety reports by your supervisor. After each year the safety report must be updated. Any person conducting work in rooms JHE-240 using this SOP must receive training on the contents of this SOP. #9 Approval Required All research staff must have WHMIS Training; and Specific Workplace Training prior to starting work with concentrated acids. Always ask a second person to be in the lab with you when working with concentrated acids. If you have to work with concentrated acids and you are alone, you have to ask for approval from your supervisor and the Person In-charge, Laboratory Manager Ed McCaffery. #10 Decontamination All glassware and measuring cylinders that have been used during the process of mixing of acid should be thoroughly rinsed with Distilled water (3 times) and then soap and water (1 time). Collect first three rinseate as hazardous waste. #11 Designated Area When preparing the sample to be digested in the container; the container must be in the fumehood when adding the acids. Filling and rinsing of the container should only be done with secondary containment tray. Upon leaving a designated work area, remove any personal protective equipment worn and wash hands, forearms, face, and neck. After each use (or day), wipe down the immediate work area and equipment to prevent accumulation of chemical residue. At the end of each project, thoroughly. Decontaminate the designated area before resuming normal laboratory work in the area.
#12 Precise Process Description 1. Metal samples should be drill turnings, non metal samples should be homogenous powders, weigh out the sample (no greater than 0.1 grams) using the precision balance (located in room 239), make sure you record the weight. 2. Place the sample into the Teflon container. If you are weighing more than 1 sample use the container holder which has been numbered so you can keep tract of the samples. 3. Determine from the Milestone methods the appropriate acid mixtures and temperature/ time profile for complete sample digestion. Inspect the Special spring, TFM cover plate, adapter plate, and TRM Vessel for any defects. 4. Take the first sample and put it into the #1 microwave rotor segment, this segment will house the thermocouple. a. Complete assembly consists of a TFM vessel, Indicator ring (not for # 1 Rotor segment), Adaptor plate, Special ring, Protection shield. b. Place the TFM vessel into the pressure Protection shield, then put the TFM cover and adapter plate, and Special spring on the top. Then put into pressure containment vessel. c. Put the entire assembly into the Rotor segment d. Place the rotor segment into the holder, using the torque wrench screw the top down until the torque wrench clicks. e. Place rotor segment into the microwave oven rotary holder. 5. Repeat step four until all of the Rotary segments are properly assembled. Note that for the rest of the rotary segments you must place the indicator ring onto the assembly, making sure that the indicator ring hole is facing away from you. 6. Connect the thermocouple to the inside of the oven, aligning the black lines. 7. Run the appropriate program. 8. Once digestion is complete wait until the temperature is close to room temperature. 9. Remove the thermocouple by TUGGING GENTLY ON THE METAL END CONNECTOR ONLY. Tugging on the cord will damage or break the thermocouple wire. 10. Disassemble the rotor segment and carefully transfer the liquid to a volumetric flask. Ensure that the sample is completely digested and in solution, small un-dissolved particles will affect the results of the analysis and can also plug up the ICP. Make sure you rinse the TFM vessel thoroughly with distilled water. Fill to mark on volumetric flask.
Laboratory Spill Response Procedures Health Threatening Situation - In the event of an imminent or actual health-threatening emergency (threatening local or public health, safety, or welfare; or the environment outside the immediate area): 1) CALL 88 FOR THE EMERGENCY RESPONSE REMAIN IN THE AREA TO ADVISE RESPONDERS. 2) ACTIVATE LOCAL ALARM SYSTEMS 3) Once personal safety is established, call EOHSS at Ext 24352 and proceed with local notifications, below. Non-Health Threatening Situation In the event of a spill or release which may or has impacted the environment (storm drain, soil, air outside the building) or spill or release that cannot be cleaned up by local personnel: 1) Notify McMaster Responders: Call 88 (24 hours/day, 7 days/week), then 2) Provide local notifications: Name Phone Number Title Ed McCaffery Ext 24985 Lab Manager/ Principle Investigator Lisa Morine Ext 23314 EOHSS Local Response Situation In the event of a minor spill or release that can be cleaned up by local personnel using readily available equipment (absorbent, available from EOHSS in Spill Kit): 1) Notify personnel in the area and restrict access. Eliminate all sources of ignition. 2) Wear gloves and protective eyewear. Clean up using absorbent. Put the contaminated absorbent in a labeled hazardous waste container. 3) If greater than 30 ml, or cleanup takes longer than 15 minutes, make a record in your lab inspection report, or call 88 Emergency Response to record the spill, and notify your supervisor. 4) Submit online waste pickup request to EHOSS at: waste@mcmsater.ca Disclaimer: The SOP as written contains our best understanding at this time on how to work safely with this piece of equipment. When new information is found that would improve the safe use of this equipment it will be added in a timely manner. As it stands we cannot be held liable for misuse or abuse of these instructions through negligence on the user s part or based on the content of these notes.