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- Posts: 17
- Joined: Fri Nov 26, 2010 10:02 pm
Hi all!
I'm a long time lurker, first time poster looking for some advice from anyone who is familiar or has ideas about how to isolate where our Bis(2-ethylhexyl)phthalate (and to some extent Bis(2-ethylhexyl)adipate) contamination is coming from. We are a small/medium size environmental laboratory and I perform the extraction prep and my partner runs the GC-MS. Although I haven't been trained on the analytical side (yet), I will try to give all the info I can about both parts. I do believe the contamination is coming more from the extraction end anyway since the unextracted calibration and verification standards do not exhibit unwanted detections. It shows up as randomly in my method prep blanks/standards as it does in my samples (but not always duplicates or spikes, and vice versa.)
For the extraction, we utilize EMD or Fisher HPLC grade methanol, ethyl acetate and methylene chloride. The pre-preserved sample containers are from C&G, whom we have had minimal issues/interferences at least in regards to the rest of our SOC kits. I rinse absolutely everything with copious amounts of 1EtoAC:1MeCl that comes into contact with samples/extracts and have dedicated all glassware involved. I initially rinse/condition our C18's (3M) with 3-10 mL aliquots of the 1:1 and follow with the 10 mL of methanol and 2-10 mL water rinses, being sure to include resevoir walls as well. We use a large CPI 6-station manifold to pull the sample through and during the extraction, I began covering the tops with foil which has seemed to help a little but not enough to consistently be below the trigger level, which I believe is 3 ppb. Does anyone have any luck with a particular brand of C18 disks/cartridges or maybe utilize a closed-system instrument in their extraction? I have called 3M, who assures me it's not coming from them and we have tried a sample package of Varian SPEC as well, without luck. I have recently rectified a recovery problem for method 549.2 using UCT and am very impressed with their quality (and promptly dumped the problematic vendor.) However to attempt using UCT 525.2 supplies, I would have to purchase quite a few things to get started, which I don't want to do unless it's logical to suspect that the hits are likely coming from the supplies. We also thought about just leaving some beakers of solvent around in the hoods, on the bench, etc. and then concentrating those just to see if maybe it's just actually divebombing in, which may account for the randomness in that respect. (Incidentally, I had stopped wearing nitrile gloves as a precaution but I'm really not comfortable doing this. Does anyone have any ideas on hand protection that wouldn't be a problem?)
The GC-MS we use is an Agilent 6850/5975B (love Agilent!) I'm not sure about the method specs as far as temp, ramping, voltage, etc. but can find out if anyone has questions or advice. We use Agilent's orange no-bleed/non-stick septas but I believe we've tried Supelco's Thermogreen septas which made no difference. We also use a J&W DB-5MS column and either Restek or Agilent gooseneck splitless liners. I'm not sure about the other bits, but we tend to stick with those two companies since they haven't failed us yet.
If anyone has any ideas, I'm all ears. I have literally tried absolutely everything I can possibly think of with varying success but not enough. Since we are a NELAP accreditied lab, I am really feeling the heat on this and all the documentation involved to get it up and running again. It's just that the only thing I hate more than the current sub'ing out of our own tests is not being absolutely sure that it isn't our fault if a client is forced into additional monitoring.
Please feel free to offer any suggestions, no matter how small and thanks in advance for your time!!
I'm a long time lurker, first time poster looking for some advice from anyone who is familiar or has ideas about how to isolate where our Bis(2-ethylhexyl)phthalate (and to some extent Bis(2-ethylhexyl)adipate) contamination is coming from. We are a small/medium size environmental laboratory and I perform the extraction prep and my partner runs the GC-MS. Although I haven't been trained on the analytical side (yet), I will try to give all the info I can about both parts. I do believe the contamination is coming more from the extraction end anyway since the unextracted calibration and verification standards do not exhibit unwanted detections. It shows up as randomly in my method prep blanks/standards as it does in my samples (but not always duplicates or spikes, and vice versa.)
For the extraction, we utilize EMD or Fisher HPLC grade methanol, ethyl acetate and methylene chloride. The pre-preserved sample containers are from C&G, whom we have had minimal issues/interferences at least in regards to the rest of our SOC kits. I rinse absolutely everything with copious amounts of 1EtoAC:1MeCl that comes into contact with samples/extracts and have dedicated all glassware involved. I initially rinse/condition our C18's (3M) with 3-10 mL aliquots of the 1:1 and follow with the 10 mL of methanol and 2-10 mL water rinses, being sure to include resevoir walls as well. We use a large CPI 6-station manifold to pull the sample through and during the extraction, I began covering the tops with foil which has seemed to help a little but not enough to consistently be below the trigger level, which I believe is 3 ppb. Does anyone have any luck with a particular brand of C18 disks/cartridges or maybe utilize a closed-system instrument in their extraction? I have called 3M, who assures me it's not coming from them and we have tried a sample package of Varian SPEC as well, without luck. I have recently rectified a recovery problem for method 549.2 using UCT and am very impressed with their quality (and promptly dumped the problematic vendor.) However to attempt using UCT 525.2 supplies, I would have to purchase quite a few things to get started, which I don't want to do unless it's logical to suspect that the hits are likely coming from the supplies. We also thought about just leaving some beakers of solvent around in the hoods, on the bench, etc. and then concentrating those just to see if maybe it's just actually divebombing in, which may account for the randomness in that respect. (Incidentally, I had stopped wearing nitrile gloves as a precaution but I'm really not comfortable doing this. Does anyone have any ideas on hand protection that wouldn't be a problem?)
The GC-MS we use is an Agilent 6850/5975B (love Agilent!) I'm not sure about the method specs as far as temp, ramping, voltage, etc. but can find out if anyone has questions or advice. We use Agilent's orange no-bleed/non-stick septas but I believe we've tried Supelco's Thermogreen septas which made no difference. We also use a J&W DB-5MS column and either Restek or Agilent gooseneck splitless liners. I'm not sure about the other bits, but we tend to stick with those two companies since they haven't failed us yet.
If anyone has any ideas, I'm all ears. I have literally tried absolutely everything I can possibly think of with varying success but not enough. Since we are a NELAP accreditied lab, I am really feeling the heat on this and all the documentation involved to get it up and running again. It's just that the only thing I hate more than the current sub'ing out of our own tests is not being absolutely sure that it isn't our fault if a client is forced into additional monitoring.
Please feel free to offer any suggestions, no matter how small and thanks in advance for your time!!
"Linda, you're in charge of the lab. I leave it all to you. I don't like it down there. It's chilly, the people are odd, and it smells like science."
