<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto">I have used either a drop of Schiff reagent or Feulgen reagent in a small sample of fluid <br><br><div dir="ltr">With all good wishes, Simon Moore. <div>Sent from my iPhone</div><div><br></div></div><div dir="ltr"><br><blockquote type="cite">On 24 May 2021, at 23:31, Irene Finkelde <irenefinkelde@gmail.com> wrote:<br><br></blockquote></div><blockquote type="cite"><div dir="ltr"><div dir="ltr"><font face="arial, sans-serif" color="#000000">Hi Paul</font><div><font face="arial, sans-serif" color="#000000"><br></font></div><div><font face="arial, sans-serif" color="#000000">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. </font></div><div><font face="arial, sans-serif" color="#000000"><br></font></div><div><font face="arial, sans-serif" color="#000000">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. </font></div><div><p class="MsoNormal" style="margin:0cm 0cm 0.0001pt;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><font color="#000000" face="arial, sans-serif">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. <span lang="EN-US">Even though the sample was diluted the drops of titrant were still counted as though each drop represented 0.05% formaldehyde.</span><span lang="EN-US"></span></font></p><p class="MsoNormal" style="margin:0cm 0cm 0.0001pt;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><font color="#000000" face="arial, sans-serif"><span lang="EN-US">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. </span></font></p><p class="MsoNormal" style="margin:0cm 0cm 0.0001pt;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><font face="arial, sans-serif" color="#000000"><br></font></p><p class="MsoNormal" style="margin:0cm 0cm 0.0001pt;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><font color="#000000" face="arial, sans-serif">Happy to discuss with you if you have any questions. </font></p><p class="MsoNormal" style="margin:0cm 0cm 0.0001pt;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><font color="#000000" face="arial, sans-serif"><br></font></p><p class="MsoNormal" style="margin:0cm 0cm 0.0001pt;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><font color="#000000" face="arial, sans-serif">Irene Finkelde </font></p></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, May 25, 2021 at 4:00 AM Callomon,Paul <<a href="mailto:prc44@drexel.edu">prc44@drexel.edu</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
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<p class="MsoNormal">Folks,<u></u><u></u></p>
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<p class="MsoNormal">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.
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<p class="MsoNormal" style="background:white"><span style="font-size:12pt;color:black">Paul Callomon<u></u><u></u></span></p>
<p class="MsoNormal" style="background:white"><span style="font-size:12pt;color:black">Collection Manager, Malacology and General Invertebrates<i><u></u><u></u></i></span></p>
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<p class="MsoNormal" style="background:white"><b><span style="font-size:12pt;color:black">Academy of Natural Sciences of Drexel University</span></b><b><span style="font-size:12pt;color:black"><u></u><u></u></span></b></p>
<p class="MsoNormal" style="background:white"><span style="font-size:12pt;color:black">1900 Benjamin Franklin Parkway, Philadelphia PA 19103-1195, USA<br>
<i><a href="mailto:prc44@drexel.edu" target="_blank"><span style="color:rgb(5,99,193)">prc44@drexel.edu</span></a> Tel 215-405-5096 - Fax 215-299-1170</i><u></u><u></u></span></p>
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