Manufacturers, Distributors, and Vendors Quality Control Procedures CHAT THREAD - Page 2
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Thread: Manufacturers, Distributors, and Vendors Quality Control Procedures CHAT THREAD

  1. #11
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    Been too busy building the business to spend much time on the forums. But easing up now I've learnt to delegate

    Hi Kinabaloo too - long time no see

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    The BE thing was something of a nightmare for me because it is real hard to get a balance and also to make posts in a public forum where one is focussing on one audience and and unintentended audience objects. I still feel the 'attack' on Brad went too far, on a personal level where it had morphed to basically guesswork. Nonetheless BE had a sustained track record of general carelessness; yet it's still a leap to persoanlise that and not offer a hand of reconciliation. Who knows if I'm right though; the errors were serious and sustained. Overall, I still feel it went/is going too far. And while there are many tremendously good things to come out of it - the test kit, the focus on QA/QC and how something like the UK trade association (hello to Kat btw) might evolve elsewhere, some negatives too. Such as small vendors being plagued by indignant questions about nicotine sources and their testing procedures. Can't disagree with the intent, but all the same ...
    Last edited by kinabaloo; 11-27-2011 at 02:03 AM.

  3. #13
    Registered Supplier ECF Veteran AriM's Avatar
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    As much as we would love to believe manufacturers/re-distributors claims and labeling, I still think it's wise/prudent to do full (pH/indicator) titrations on each batch of nic base we receive, and again after cutting the base down to mixing strength. This is especially wise (IMO) when we are doing large base dilutions, simply because a mistake here can cost a pretty penny.

    I usually run the titration 3 times at each dilution stage, and then average the results against the predicted outcome. If it's off by more than a mg/ml or so, I usually throw the batch away or look for a root cause in the testing procedure.

    It's also wise to do a density test on the HCl used for the titration, as this can swing results beyond the margin of acceptable error. Nothing is worse than throwing out a few gallons of base, only to realize (after density testing) that the HCl was mislabeled or contaminated.

    After a few lessons learned, I never dilute the HCl myself anymore. I only use certified/sealed solutions, from reputable suppliers.

    I'm not trying to make excuses for anyone, but I think a lot of the responsibility of QC lies on our shoulders (as manufacturers of bottled e-liquid).

    Let me pose an example. When XYZ auto manufacturer buys a part for a automobile (let say something as simple as a bolt), they do rely on the manufacturers specifications (for said part) as a general guideline. They go one step further though and do full in house (as well as 3rd party) evaluation of that bolt.

    I think we should all take that same level of responsibility. It's not saying that we should take steps that lead to pricing ourselves out of the market, but some very basic homework and accountability is within the reach of even the smallest company. If not for the sake of moral standing, then for the sake of the bottom line.

    I know I personally wouldn't sleep well, knowing I am sending out unverified nicotine levels. I hope this doesn't come off as snide or arrogant. I am just a bit shocked that some people have tried to pass off their own lack of QC to the next supplier in the food chain. Not pointing fingers, but nothing is ever 100% on someone else. I tested quite a few suppliers nic base before deciding on a regular source, and even then I still test each and every containers contents. People make mistakes. It's far too easy to pass the buck.
    Last edited by AriM; 04-15-2012 at 03:52 AM.

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    AriM, no need to toss out HCl. What you need is solid anhydrous potassium hydrogen phthalate (KHP) and aqueous 0.01 M NaOH. And an analytical balance (something that all mixing vendors should get...see density thread).

    1. Weigh accurately about 0.48 g of KHP. Best to have about 4 samples of this. I weigh to 4 sig figs.

    2. Titrate each KHP sample with phenolphthalein indicator to a barely pink end point, with the NaOH(aq). Calculate the molarity of the NaOH(aq). Use a buret. You should be able to get the molarity to 4 places past the decimal within a 1% std deviation. Now the NaOH is standardized.

    3. Titration the HCl against the NaOH with phenolphthalein. Do several titrations to increase precision. Calculate the HCl molarity. I shoot for 4 sig figs and about 1% error. Now the HCl is standardized and I can use it for pH curve titrations for nicotine content.

    4. Once every few weeks, restandardize the NaOH (its conc will drift due to CO2 absorption), and restandardize the HCl. HCl won't drift like NaOH will, but I do it anyway to be sure.

    PM me if you need details about glassware and other questions.
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    Also, I don't think the vendors actually knew there were problems until there were complaints. Not trying to defend them...I'm with you: when it comes to something a potentially dangerous as nic, I would be very precise and accurate. But the vendors I have dealt with have for the most part been very concerned about getting it right. They simply did not have the chemistry knowledge to know what that meant.

    This was illustrated dramatically to me when I published essentially freshman chemistry titration curve results, and people thought I had done magic. If I have done nothing else for this community, at least there is much more chemistry knowledge now. Still a ways to go, but the consciousness has been increased significantly.
    Deciding not to smoke is one thing. Forgetting to smoke is a different animal altogether.

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    Registered Supplier ECF Veteran AriM's Avatar
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    Quote Originally Posted by Kurt View Post
    AriM, no need to toss out HCl. What you need is solid anhydrous potassium hydrogen phthalate (KHP) and aqueous 0.01 M NaOH. And an analytical balance (something that all mixing vendors should get...see density thread).

    1. Weigh accurately about 0.48 g of KHP. Best to have about 4 samples of this. I weigh to 4 sig figs.

    2. Titrate each KHP sample with phenolphthalein indicator to a barely pink end point, with the NaOH(aq). Calculate the molarity of the NaOH(aq). Use a buret. You should be able to get the molarity to 4 places past the decimal within a 1% std deviation. Now the NaOH is standardized.

    3. Titration the HCl against the NaOH with phenolphthalein. Do several titrations to increase precision. Calculate the HCl molarity. I shoot for 4 sig figs and about 1% error. Now the HCl is standardized and I can use it for pH curve titrations for nicotine content.

    4. Once every few weeks, restandardize the NaOH (its conc will drift due to CO2 absorption), and restandardize the HCl. HCl won't drift like NaOH will, but I do it anyway to be sure.

    PM me if you need details about glassware and other questions.
    Great stuff there Kurt. Does the KHP need to be prepped in a nitrogen environment though? I mean can it absorb enough H2O in free air to become contaminated? I was considering investing in a closed titration system (semi-automated) to try and remove some of the human error, and speed up the process.

    How much more consistent do you expect I could get my results with "standardized" HCl?

  7. #17
    Registered Supplier ECF Veteran AriM's Avatar
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    Quote Originally Posted by Kurt View Post
    Also, I don't think the vendors actually knew there were problems until there were complaints. Not trying to defend them...I'm with you: when it comes to something a potentially dangerous as nic, I would be very precise and accurate. But the vendors I have dealt with have for the most part been very concerned about getting it right. They simply did not have the chemistry knowledge to know what that meant.

    This was illustrated dramatically to me when I published essentially freshman chemistry titration curve results, and people thought I had done magic. If I have done nothing else for this community, at least there is much more chemistry knowledge now. Still a ways to go, but the consciousness has been increased significantly.
    I am sure they didn't know Kurt, but that is the part that scares me above all else. I don't want to come off as being against anyone or anything, but we are dealing with a drug....that may well have to be treated as such (from a regulatory standpoint) in the very near future. I wish there was a coalition of vendors/mixers here in the USA, where people who don't have the access to information and gear, can get some help. At the very least some form of mandate within the industry, stating that such testing is necessary...and to avoid in house testing is bordering on negligence. I'm no lawyer, but that is the way I think a court of law would view it, should anyone ever become injured (and make claims against a vendor of "e-liquid"). Obviously such cases go after the deepest pockets, but I would hate to see some national (sensationalized) scandal against the vaping industry, just because a few folks were negligent.

    I appreciate the information you have given out, as it benefits us all.

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    Quote Originally Posted by AriM View Post
    Great stuff there Kurt. Does the KHP need to be prepped in a nitrogen environment though? I mean can it absorb enough H2O in free air to become contaminated? I was considering investing in a closed titration system (semi-automated) to try and remove some of the human error, and speed up the process.

    How much more consistent do you expect I could get my results with "standardized" HCl?
    No, KHP can generally just sit in a plastic jar without any water absorption. Its the great goto for acid/base standardization, since you get moles accurately from the mass, and its monobasic. Its really the only way I use for this application, and we use it regularly for teaching lab titrations.

    More titrations means more data to average over and lower std dev. My goal was to get nic to 4 sig figs. Some vendors have published nic levels of, say, 36.4532 mg/mL, but were using 0.1 M acid. That's only one sig fig, so you really could only report 40 mg/mL. Just because the calculator is telling you lots of places past the decimal does NOT mean you actually know and can support those digits.

    I standardize the HCl. Then use a 10.00 mL vol syringe to put 10.00 mL of an unflavored liquid into a 100.00 mL vol flask, and dilute to the meniscus line. Then I pipet 25.00 mL of that into my titration beaker (I use a stir-bar and pH probe), and titrate it with the acid. My acid this last time was 0.07052M standarized. I do three titrations from the 100.00 mL solution, then repeat the whole thing with a new nic-liquid 10.00 mL, which total gives me 6 titrations that I average over. I want <1% relative std dev in the end, and 4 sig figs. The titrations are pH curves and I use a spreadsheet to calculate the inflection point (Max negative slope, at equivalence point). A bit of work, but not bad, and the results are air-tight. That's how I did the original BE samples.
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    Quote Originally Posted by AriM View Post
    I am sure they didn't know Kurt, but that is the part that scares me above all else. I don't want to come off as being against anyone or anything, but we are dealing with a drug....that may well have to be treated as such (from a regulatory standpoint) in the very near future. I wish there was a coalition of vendors/mixers here in the USA, where people who don't have the access to information and gear, can get some help. At the very least some form of mandate within the industry, stating that such testing is necessary...and to avoid in house testing is bordering on negligence. I'm no lawyer, but that is the way I think a court of law would view it, should anyone ever become injured (and make claims against a vendor of "e-liquid"). Obviously such cases go after the deepest pockets, but I would hate to see some national (sensationalized) scandal against the vaping industry, just because a few folks were negligent.

    I appreciate the information you have given out, as it benefits us all.
    Definitely working on it. Contact Lone Wolf (Gary) to see where things are with a project that is being created for mass GC-MS sampling. He has a thread in this QC forum, but I'm not sure what the status is.

    Other projects too, but while things are moving forward to create self-regulation standards, its a slow process. I am most certainly doing what I can, with the help of particular vendors.
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  10. #20
    Registered Supplier ECF Veteran AriM's Avatar
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    Quote Originally Posted by Kurt View Post
    No, KHP can generally just sit in a plastic jar without any water absorption. Its the great goto for acid/base standardization, since you get moles accurately from the mass, and its monobasic. Its really the only way I use for this application, and we use it regularly for teaching lab titrations.

    More titrations means more data to average over and lower std dev. My goal was to get nic to 4 sig figs. Some vendors have published nic levels of, say, 36.4532 mg/mL, but were using 0.1 M acid. That's only one sig fig, so you really could only report 40 mg/mL. Just because the calculator is telling you lots of places past the decimal does NOT mean you actually know and can support those digits.

    I standardize the HCl. Then use a 10.00 mL vol syringe to put 10.00 mL of an unflavored liquid into a 100.00 mL vol flask, and dilute to the meniscus line. Then I pipet 25.00 mL of that into my titration beaker (I use a stir-bar and pH probe), and titrate it with the acid. My acid this last time was 0.07052M standarized. I do three titrations from the 100.00 mL solution, then repeat the whole thing with a new nic-liquid 10.00 mL, which total gives me 6 titrations that I average over. I want <1% relative std dev in the end, and 4 sig figs. The titrations are pH curves and I use a spreadsheet to calculate the inflection point (Max negative slope, at equivalence point). A bit of work, but not bad, and the results are air-tight. That's how I did the original BE samples.
    Kurt I am running my titrations the exact same way. I am using a grade A (certified) vessel and burette. I run the titration against bromothymol AND a calibrated pH meter (I calibrate before each titration). I use a magnetic stirrer/stir bar combo to keep the solution homogonized.

    I run the titration 3 times on each dilution stage, and average against the predicted result. Unless I run into a large gap between those numbers. If I do see that large gap, I usually clean and calibrate everything again and start over (I clean the burette with HCl, and the other items with distilled and heat).

    I am very curious about generating a pH curve though. That is NOT something I am doing. This is why I wanted to invest in the instrument from HANNA. It does the curves automatically, and spits them out (via USB) to your database.

    Do you think it's unnecessary to get beyond 1% accuracy? I know that if we were required to present our reports to a regulatory commission, we we be grossly un-prepared.

    Thanks again for the information Kurt. You are probably doing more to keep this industry safe than most people realize.

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