[Nhcoll-l] Formalin testing

[Irene Finkelde]

Hi Paul

A few years ago I did some research into different methods to test
formaldehyde concentration in fluid preservatives. I tested two brands of
test strips, a commercially available titration kit, and a titration method
(originally developed by Robert Waller and refined very slightly by
myself). The full article will be published in Collection Forum soon.

You could try using the commercially available titration test kit (Hach
Formaldehyde Test Kit: Model FM-1). This can test formaldehyde
concentration in solution within the ranges of either 0.05 - 1% or 0.5% -
10% formaldehyde in solution (terminology is important when using the test
and interpreting the results – what we often call “10% formalin” is 4% w/v
formaldehyde gas in water). The manual can be downloaded from the Hach
website if you want to look at the titration method before you purchase it.

The solid reagent supplied with this test kit is insoluble in ethanol,
which is an issue when testing for residual formalin in alcohol solutions
and following the manufacturers instructions. When I tested ethanol
solutions, I adapted the method and I first dissolved the contents of the
reagent sachet in a beaker with 10ml demineralised water and added that to
the sample before titration. Even though the sample was diluted the drops
of titrant were still counted as though each drop represented 0.05%
formaldehyde.

I preferred using titration methods to the test strips, as it is easier to
quantify the results and I found the test strips to be quite time consuming
to get a result, as multiple dilutions can be required.


Happy to discuss with you if you have any questions.


Irene Finkelde

On Tue, May 25, 2021 at 4:00 AM Callomon,Paul <prc44 at drexel.edu> wrote:

> Folks,
>
>
>
> Here in the USA, what do you use to test for formaldehyde in alcohol
> solutions? We used to have test strips, but I’m having trouble finding
> something cheap and reliable now.
>
>
>
> Paul Callomon
>
> Collection Manager, Malacology and General Invertebrates
> ------------------------------
>
> *Academy of Natural Sciences of Drexel University*
>
> 1900 Benjamin Franklin Parkway, Philadelphia PA 19103-1195, USA
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>
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