4 ms·

Wish there were some way to detect impurities like this at home.

by loopdoend 1y ago

pfdietz 1y ago
Hand held x-ray fluorescence spectrometer?
- unixhero 1y ago
  But of course!
- perihelions 1y ago
  I think those cost more than my entire kitchen.
  - pfdietz 1y ago
    Hey, if Nile Red can use one, so can you!
- jpmattia 1y ago
  And just like that, there was a mad rush of mass-spectrometer-for-home-use startups.
  - fuzzfactor 1y ago
    X-ray fluorescence detects elements based on their characteristic electromagnetic spectrum when irradiated with x-rays. Not very much like a mass-spectrometer which creates a characteristic pattern of masses resulting from the test material as it is manipulated by the electron ionization or chemical ionization process. Where ions are detected across the atomic mass range of the particular spectrometer, forming a characteristic pattern or "spectrum" across that range. Actually more jewelers and gold dealers than ever are using the x-ray guns professionally for bulk assay on an everyday basis. There are some handhelds which may be sensitive enough for trace analysis in food, but that requires a whole nother level of dedication beyond identification of metal objects, not just in technique and training but "laboratory" preparation as well. The first obstacle would be convincing an owner of an instrument having capable specs, to embrace usage for things other than gold and silver assay. Then seriously pursue mastery of the instrument more so than ever to accomplish decent detection of low levels of lead and other metals like chromium, mercury, cadmium, etc.
    - pfdietz 1y ago
      The concentrations of lead being discussed here are as much as 1000 ppm or even higher.
      - kragen 1y ago
        Quoting perihelions's comment above: [1] https://pubmed.ncbi.nlm.nih.gov/25214856/ https://pubmed.ncbi.nlm.nih.gov/25214856/ ("Contaminated turmeric is a potential source of lead exposure for children in rural Bangladesh" / "Results: Lead concentrations in many turmeric samples were elevated, with lead concentrations as high as 483 ppm")
        fuzzfactor 1y ago
        >as much as 1000 ppm or even higher. The higher it is, the less likely for challenges in detection, and/or interference from background. >lead concentrations as high as 483 ppm SSDD. Shouldn't be that hard to detect at that level which is way above ppb. There are a number of reliable methods. However if the Minimum Detectable Level for a particular test procedure was only 500 ppm or above, one of these samples would report just as clean as a sample having no lead whatsoever; < 500. MDL's like this which vary among different test methods do need to be carefully compared to the toxicity levels being screened for. That's another one of the confounding aspects to be aware of. Depending on circumstances, I may or may not prefer a different calibration session for each of these two levels, even though they are both within the same order of magnitude. Either way ideally I would be preparing NIST-traceable reference materials at the proper levels for comparison & confirmation. Not much differently than I would do for the benchtop models and the forklift models of x-ray units. And to really get down into the ppb levels that's when the ICP/mass-spec comes in handy, that's a benchtop unit itself, too big to fit on a regular desk though. However you don't really get the most out of the ICP without a huge cryogenic tank of liquid argon out back so you can "consume mass quantities" ;) With a handheld x-ray unit, if you are only assaying gold & silver it may be fine to send it back for calibration once a year, if the pawn shops even do that. For food testing I would want more of a laboratory-style analytical procedure and calibration which is concurrent with materials being tested.
Joel_Mckay 1y ago
There are very sensitive indicator drops used for identifying ceramic glazes containing lead on antique porcelain. There are also handheld scanners that cost more than a car. And yes, people in the community scan every imported toy and or food item they see to start the FDA ban process when necessary. Should buy local when you can anyway. =3
- account42 1y ago
  Tumeric isn't something grown locally in most places. And for powder you are pretty much always getting imports.
  - Joel_Mckay 1y ago
    I think you mean it isn't unrealistically cheap locally, or from reputable certified organic farmers. Have a great day =3
    - account42 1y ago
      No I mean it isn't grown locally for sale at all.
bluGill 1y ago
I have found lead detection kits. However they are somewhat expensive and I'm not sure how well they work.
- Joel_Mckay 1y ago
  Really? Lead test kits are $10 on amazon, and will include several dozen tests. The better kits will include paper to verify the tests still are working (short shelf life in the open.) The sodium rhodizonate tests usually turn pink in the presence of traces of lead. These tests are intended for testing paints/ceramics, and may have false positives in the presence of zinc or copper etc. Our local Griefers seem to have strong feelings about this information, but talk with your chemistry teacher if you want to understand the details about testing. If a credible 3M brand test shows possible contamination, than consider sending a sample into a lab to figure out the details. =3
  - account42 1y ago
    Those tests are not sensitive enough to check for food contamination.
    - Joel_Mckay 1y ago
      The contamination is powdered paint containing white lead pigment, and many of these 20ppm to 500ppm test kits are designed for paint surface testing. If you are color blind and cant see pink very well, than get someone to help or go the lab test route. Best of luck =3
      - account42 1y ago
        I think you're the one in need of luck if you're going to rely on paint tests for food safety.
        Joel_Mckay 1y ago
        Normal people don't consider paint food, and don't eat the test kits. The "Do not ingest" labels are on the side for people that may assume otherwise. lol =3
whiw 1y ago
I am not a chemist, so take this with a pinch of salt: wouldn't lead chromate + sodium bicarbonate make lead carbonate, a white precipitate? Sodium bicarbonate is likely in your kitchen cupboard already.
- adrianN 1y ago
  Pretty hard to see precipitated dust at concentrations in the ppm range.
- whiw 1y ago
  I meant lead carbonate, not lead oxide.
- BenjiWiebe 1y ago
  Not a chemist either but lead oxide is actually more soluble in water than lead chromate, so a double replacement reaction won't favor lead chromate -> lead oxide.
- kragen 1y ago
  WP tells me lead chromate's solubility in water is 0.00001720 g/100 mL, so, no, it won't.
ashwinsundar 1y ago
https://eatrightindia.gov.in/dart/#:~:text=Test%2014%20%3A%20Detection%20of%20lead%20chromate%20in%20turmeric%20whole https://eatrightindia.gov.in/dart/#:~:text=Test%2014%20%3A%2...
gitaarik 1y ago
This Indian gov YouTube channel has all kinds of videos for that: https://www.youtube.com/watch?v=tXWPf0HQd5U https://www.youtube.com/watch?v=tXWPf0HQd5U

Wish there were some way to detect impurities like this at home.

pfdietz 1y ago

Hand held x-ray fluorescence spectrometer?

unixhero 1y ago
But of course!
perihelions 1y ago
I think those cost more than my entire kitchen.
- pfdietz 1y ago
  Hey, if Nile Red can use one, so can you!
jpmattia 1y ago
And just like that, there was a mad rush of mass-spectrometer-for-home-use startups.
- fuzzfactor 1y ago
  X-ray fluorescence detects elements based on their characteristic electromagnetic spectrum when irradiated with x-rays. Not very much like a mass-spectrometer which creates a characteristic pattern of masses resulting from the test material as it is manipulated by the electron ionization or chemical ionization process. Where ions are detected across the atomic mass range of the particular spectrometer, forming a characteristic pattern or "spectrum" across that range. Actually more jewelers and gold dealers than ever are using the x-ray guns professionally for bulk assay on an everyday basis. There are some handhelds which may be sensitive enough for trace analysis in food, but that requires a whole nother level of dedication beyond identification of metal objects, not just in technique and training but "laboratory" preparation as well. The first obstacle would be convincing an owner of an instrument having capable specs, to embrace usage for things other than gold and silver assay. Then seriously pursue mastery of the instrument more so than ever to accomplish decent detection of low levels of lead and other metals like chromium, mercury, cadmium, etc.
  - pfdietz 1y ago
    The concentrations of lead being discussed here are as much as 1000 ppm or even higher.
    - kragen 1y ago
      Quoting perihelions's comment above: [1] https://pubmed.ncbi.nlm.nih.gov/25214856/ https://pubmed.ncbi.nlm.nih.gov/25214856/ ("Contaminated turmeric is a potential source of lead exposure for children in rural Bangladesh" / "Results: Lead concentrations in many turmeric samples were elevated, with lead concentrations as high as 483 ppm")
      - fuzzfactor 1y ago
        >as much as 1000 ppm or even higher. The higher it is, the less likely for challenges in detection, and/or interference from background. >lead concentrations as high as 483 ppm SSDD. Shouldn't be that hard to detect at that level which is way above ppb. There are a number of reliable methods. However if the Minimum Detectable Level for a particular test procedure was only 500 ppm or above, one of these samples would report just as clean as a sample having no lead whatsoever; < 500. MDL's like this which vary among different test methods do need to be carefully compared to the toxicity levels being screened for. That's another one of the confounding aspects to be aware of. Depending on circumstances, I may or may not prefer a different calibration session for each of these two levels, even though they are both within the same order of magnitude. Either way ideally I would be preparing NIST-traceable reference materials at the proper levels for comparison & confirmation. Not much differently than I would do for the benchtop models and the forklift models of x-ray units. And to really get down into the ppb levels that's when the ICP/mass-spec comes in handy, that's a benchtop unit itself, too big to fit on a regular desk though. However you don't really get the most out of the ICP without a huge cryogenic tank of liquid argon out back so you can "consume mass quantities" ;) With a handheld x-ray unit, if you are only assaying gold & silver it may be fine to send it back for calibration once a year, if the pawn shops even do that. For food testing I would want more of a laboratory-style analytical procedure and calibration which is concurrent with materials being tested.

Joel_Mckay 1y ago

There are very sensitive indicator drops used for identifying ceramic glazes containing lead on antique porcelain. There are also handheld scanners that cost more than a car. And yes, people in the community scan every imported toy and or food item they see to start the FDA ban process when necessary. Should buy local when you can anyway. =3

account42 1y ago
Tumeric isn't something grown locally in most places. And for powder you are pretty much always getting imports.
- Joel_Mckay 1y ago
  I think you mean it isn't unrealistically cheap locally, or from reputable certified organic farmers. Have a great day =3
  - account42 1y ago
    No I mean it isn't grown locally for sale at all.

bluGill 1y ago

I have found lead detection kits. However they are somewhat expensive and I'm not sure how well they work.

Joel_Mckay 1y ago
Really? Lead test kits are $10 on amazon, and will include several dozen tests. The better kits will include paper to verify the tests still are working (short shelf life in the open.) The sodium rhodizonate tests usually turn pink in the presence of traces of lead. These tests are intended for testing paints/ceramics, and may have false positives in the presence of zinc or copper etc. Our local Griefers seem to have strong feelings about this information, but talk with your chemistry teacher if you want to understand the details about testing. If a credible 3M brand test shows possible contamination, than consider sending a sample into a lab to figure out the details. =3
- account42 1y ago
  Those tests are not sensitive enough to check for food contamination.
  - Joel_Mckay 1y ago
    The contamination is powdered paint containing white lead pigment, and many of these 20ppm to 500ppm test kits are designed for paint surface testing. If you are color blind and cant see pink very well, than get someone to help or go the lab test route. Best of luck =3
    - account42 1y ago
      I think you're the one in need of luck if you're going to rely on paint tests for food safety.
      - Joel_Mckay 1y ago
        Normal people don't consider paint food, and don't eat the test kits. The "Do not ingest" labels are on the side for people that may assume otherwise. lol =3

whiw 1y ago

I am not a chemist, so take this with a pinch of salt: wouldn't lead chromate + sodium bicarbonate make lead carbonate, a white precipitate? Sodium bicarbonate is likely in your kitchen cupboard already.

adrianN 1y ago
Pretty hard to see precipitated dust at concentrations in the ppm range.
whiw 1y ago
I meant lead carbonate, not lead oxide.
BenjiWiebe 1y ago
Not a chemist either but lead oxide is actually more soluble in water than lead chromate, so a double replacement reaction won't favor lead chromate -> lead oxide.
kragen 1y ago
WP tells me lead chromate's solubility in water is 0.00001720 g/100 mL, so, no, it won't.

ashwinsundar 1y ago

https://eatrightindia.gov.in/dart/#:~:text=Test%2014%20%3A%20Detection%20of%20lead%20chromate%20in%20turmeric%20whole https://eatrightindia.gov.in/dart/#:~:text=Test%2014%20%3A%2...

gitaarik 1y ago

This Indian gov YouTube channel has all kinds of videos for that: https://www.youtube.com/watch?v=tXWPf0HQd5U https://www.youtube.com/watch?v=tXWPf0HQd5U