Sciencemadness Discussion Board

PSE Testing

oldschool - 26-6-2012 at 19:13

Hello all,
I've been a long-time lurker in many scientific forums - here's my first post.

Before anybody gets their nickers in a twist - what I'm doing is perfectly legal.

I am in China, and I'm going to acquire some pseudoephedrine from a chemical factory here (which is not a controlled chemical, except for exports).

My problem is - the Chinese are the masters of counterfeiting. There have been scandals of fake infant formula (which contained poison), fake eggs (they bounce) and everything else under the sun, including a fake apple store.

So, I need a foolproof way of testing the product on site before making the purchase. I have so far found the following properties:
Specifications :
1. Description : Fine, white to off white crystals or powder.
2. Identification : a ) Infrared spectrum of sample is concordant with the
reference spectrum.
b) A solution of sample responds to the test for chloride
3. Melting range : Between 182° and 186°C; the range between beginning
and end of melting does not exceed 2°C
4. Specific rotation : Between + 61.0° and + 62.5° (5 % solution in water)
5. Solubility : Very soluble in water and freely soluble in alcohol.
6. pH : Between 4.6 and 6.0 (5 % solution in water)
7. Ordinary impurities : NMT 2.0 %
8. Residue on ignition : NMT 0.1 %
9. Loss on drying : NMT 0.5 %
10. Organic volatile impurities : Must pass the test
11. Assay : Between 98.0 % and 100.5 % ( dried basis )

Half of this stuff I don't yet understand, but what I am concerned about is: could they have something else with the same appearance, the same solubility and melting points, etc..?

How can I be certain?

Thanks for helping the newb...

SulfurApothecary - 26-6-2012 at 19:31

So you looked up all the information right? The easy way to test it would be taking the melting point, look at the physical properties, take the solubility's, then take the residue on ignition. The best way to do this though would be to go get a spectrum, and you can hire people to do that, (I do know you said on site).

Organicus - 27-6-2012 at 01:54

Quote: Originally posted by SulfurApothecary  
So you looked up all the information right? The easy way to test it would be taking the melting point, look at the physical properties, take the solubility's, then take the residue on ignition. The best way to do this though would be to go get a spectrum, and you can hire people to do that, (I do know you said on site).


dont test the chemical yourself, if youre in china and everything is legal as you mentioned, you just could send a sample to an analysis laboratory.

taking the melting point would be the easiest way to determine purity in your home lab.

(measured mp / literature mp) x 100 = %

oldschool - 27-6-2012 at 22:01

I guess so. Thanks.

Getting a company to test it will take time and money. Also, the problem remains that once I've bought the stuff - that's it. Whether it's fake or not that's what I'd have... End of story.

Even if I got a cheaper sample tested, they could still do the switcheroo on the big package anyway.