# What is the threshold odor number (TON) for the follow- ing sample?

## The first detectable odor occurred when the 20 mL sample was diluted to 200 mL (180 mL of odor-free water was added to the 20 mL sample)

Jun 21, 2017

The TON is 10.

#### Explanation:

The threshold odour number is the dilution factor at which the odour is just detectable.

The dilution factor is given by

color(blue)(bar(ul(|color(white)(a/a) "DF" = V_text(f)/V_text(i) color(white)(a/a)|)))" "

where ${V}_{\textrm{f}}$ and ${V}_{\textrm{i}}$ are the final and initial volumes, respectively.

In the example, you have diluted 20 mL to 200 mL.

"DF" = (200 color(red)(cancel(color(black)("mL"))))/(20 color(red)(cancel(color(black)("mL")))) = 10

and

$\text{TON} = 10$