PPM Mixture Question

From your long, rambling diatribe I managed to understand that what you want is 170ppm of 250 ml. Is that is so then divide 250 by one million and multiply by 170. So 170ppm of 250 ml is 0.0425 ml. Right???

Correct but I can't measure that so my 170ppm component will be diluted... let's say into a 1% solution which gives me 4.25 ml. but I can't measure that either... smallest I can measure is 1ml... my goal was to develop a solution % that would permit even ml measurements of both the diluted solution and how much to add to the parent one.

I think you are sort of mixing up apples and footballs. Is your submittal sample truly to be 170ml 'A' / 1,000,000ml 'B'? If it is as simple as that, and your accurate measurement is 1ml, then mix 1ml of 'A' with 5,881ml of 'B'. Mix well, then discard all but the required 250ml! Still not exact, but this exercise is already obtuse enough.

I'll ask again: Is your submittal sample truly to be a simple volume mix? I bet it isn't.

Actually, it's more like apple juice and nitro glycerin, but that's a whole other thread

Umm, yeah... it's really as simple as that... well, except for the fact that 'A' is hazardous so I really don't feel like generating 6 liters of hazardous waste. But I didn't tell you that upfront so you would not have known.

As for it being obtuse, sorry... I appreciate your input none the less.

JavaHead

After my head cleared, took an hour break for dinner, it fell into place... actually your second option was what I scribbled on a napkin while enjoying the last part of my meal. Then I was like... "Duh, way to embarrass yourself by asking stupid questions." Sorry, it was just a bad day and I was burnt out.

As previously mentioned in a different reply, component A is hazardous and the 170ppm is a regulatory limit. We are also a CESQG in regards to hazardous waste so I was trying to generate the least amount of residual solution, of which I would not have been able to justify a use for and would have to count towards my waste generation. Since we're near the upper percentile of our generation limit, we really have to be careful about generating needles amounts.

Thanks again for your reply.

Ya'll have a wonderful weekend now, ya hear?

JavaHead

Mix one part (ml) of solute (fluid-1) of C₁ concentration in Y₁ part (ml) of solvent (fluid-2)

Resultant concentration is

C₂ = C₁ / (Y₁+1)

Repeat with Y₂ parts of solvent

C₃ = C₂/(Y₂+1) = C₁/(y₁+1)(y₂+1)

And so on

Ie

C₄ = C₁/(Y₁+1)(Y₂+1)(Y₃+1)

(Note: each time 1 ml of previous stage is mixed with Yn ml of pure solvent)

for your case if I go only to two stage

C₃ = C₁/(Y₁+1)(Y₂+1)

Final mixture required is 250 ie Y₂+1 = 250

C₁=1

C₃=170ppm = 0.000170

Y₁+1 = 1/ 0.000170*250 = 23.53 ml

Y₁ = 22.53 ml

Since your accuracy is 1ml, I will double it ie

2ml of solute in 45ml of solvent this will give you 170.2128ppm solution.

Wastage of solvent is almost 45ml (you have taken only 1ml from the solution of 47ml for second stage) .

If you want to go for further refinement, then may be you should go for higher order mixing

(This is what is done in homeopathy )

Thanks or the detailed reply. I'd have to tweak it a little going that route simply because I can't show intentional exceedance of 170, it's a regulatory limit.

But, yeah... now that my head is clear and got some decent sleep... finally... I like this method an will employ it in the future.

JavaHead