[Tyyyyuuu]

I think the last dilution in this series is 1 in 5 not, as it indicates in the table, 1 in 10. Am I wrong?!?! (the unit of volume is arbitrary, but lets say mL)

[Borek]

That would mean all earlier dilutions are wrong as well, wouldn't it?

[Tyyyyuuu]

That would mean all earlier dilutions are wrong as well, wouldn't it?

Thank you for your input. I suppose the "analytical dilution" makes sense if it's intended to be relative to just the prior dilution, and not the original stock solution. But if that's the case then the last dilution is 1 in 5 relative to the penultimate dilution. 

[Borek]

No, I think you are misunderstanding something here. These dilutions are cumulative, each next one uses the previous solution.

But if that's the case then the last dilution is 1 in 5 relative to the penultimate dilution.

No, it is 1.25 (240/192).

[Tyyyyuuu]

No, I think you are misunderstanding something here. These dilutions are cumulative, each next one uses the previous solution.

But if that's the case then the last dilution is 1 in 5 relative to the penultimate dilution.

No, it is 1.25 (240/192).

I follow what you are saying, but this is my line of thinking:

From the first row in the table, to the last:

450 mL diluent + 450 mL analyte is a 1 in 2 dilution
320                 + 640                        1 in 3
240                 + 720                        1 in 4
180                 + 720                        1 in 5
130                 + 650                        1 in 6
090                 + 540                        1 in 7
055                 + 385                        1 in 8

048                 + 640                        1 in 5 (not 1 in 10)

[Borek]

048                 + 640                        1 in 5 (not 1 in 10)

Why 640 and not 192? You have changed the rules for this one line.

[Tyyyyuuu]

048                 + 640                        1 in 5 (not 1 in 10)

Why 640 and not 192? You have changed the rules for this one line.

You're right, sorry, that was an error, (but the conclusion is the same)

450 mL diluent + 450 mL analyte is a 1 in 2 dilution
320                 + 640                        1 in 3
240                 + 720                        1 in 4
180                 + 720                        1 in 5
130                 + 650                        1 in 6
090                 + 540                        1 in 7
055                 + 385                        1 in 8

048                 + 192                        1 in 5 (not 1 in 10)

[Borek]

Your results are inconsistent. Show how you got 1 in 5 in the last line and explain how you got correct results for all previous lines.

[Tyyyyuuu]

Your results are inconsistent. Show how you got 1 in 5 in the last line and explain how you got correct results for all previous lines.

Is 1 mL A plus 1 mL of water not a 1 in 2 dilution of A? That is, one unit of A in a total of 2 units of solution.

[Borek]

It is, but what about the next one?

Perhaps you are missing the fact that each next step uses not the original stock solution, but solution from the previous step? That's what 'serial' means.