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Patent Blue V
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<h2 id="use-as-dye">Use as dye</h2> <p>It is not widely used, but in Europe it can be found in <a href="/facts/Scotch_egg/y6VQ6II3">Scotch eggs</a>, certain <a href="/facts/Gummies/H5tw9Hum">jelly sweets</a>, <a href="/facts/Cura%25C3%25A7ao_(liqueur)/aLJssQ9L">blue Curaçao</a>, certain <a href="/facts/Gelatin_dessert/JvW8sRYl">gelatin desserts</a>, among others. An important advantage is the very deep color it produces even at low concentration, a disadvantage is that it fades fairly quickly when exposed to light. </p><p>In medicine, Patent Blue V is used in <a href="/facts/Lymphangiography/7onsfXzL">lymphangiography</a> and <a href="/facts/Sentinel_node_biopsy/YcYxrmYV">sentinel node biopsy</a> as a dye to color <a href="/facts/Lymph_vessel/jND0hlDu">lymph vessels</a>.<a class="footnote-ref" id="fnref:2" href="#fn:2"><sup>2</sup></a> It is also used in dental <a href="/facts/Disclosing_tablets/WARhkINJ">disclosing tablets</a> as a stain to show <a href="/facts/Dental_plaque/b67GE1pA">dental plaque</a> on teeth. </p><p>The color of the dye is <a href="/facts/PH/RnSv8D7y">pH</a>-dependent. In aqueous solution, its color will vary from a deep blue in <a href="/facts/Alkaline/s6NqPGSP">alkaline</a> or weakly <a href="/facts/Acidic/FySU18n1">acidic</a> medium to a yellow–orange in stronger acidic conditions. It is useful as a <a href="/facts/PH_indicator/Levp3yqq">pH indicator</a> for the range 0.8–3.0.<a class="footnote-ref" id="fnref:3" href="#fn:3"><sup>3</sup></a> The structure is also <a href="/facts/Redox/Pyd5RVcj">redox</a>-sensitive, changing from a reduced yellow form to an oxidized red form in solution. The <a href="/facts/Reduction_potential/PqpNUgSl">reduction potential</a> of around 0.77 <a href="/facts/Volt/KF18MXP2">volts</a> is similar to that of other triphenylmethane dyes. It is usable as a <a href="/facts/Reversible_reaction/V3Afejgb">reversible</a> redox indicator in some analytical methods.<a class="footnote-ref" id="fnref:4" href="#fn:4"><sup>4</sup></a> </p><p>Because of its pH-dependent color, Patent Blue V was included in chemistry sets from <a href="/facts/Salter_Science/zbsCjvlg">Salter Science</a> in the 1970s and 80s under the name <i>Sky Blue</i>. </p> <h2 id="regulation">Regulation</h2> <p>Patent Blue V is banned as a <a href="/facts/Food_dye/ueFCSxvC">food dye</a> in <a href="/facts/Australia/qLHpbppq">Australia</a> and <a href="/facts/US/N2ByeYrd">US</a>, because health officials in these countries suspect that it may cause allergic reactions, with symptoms ranging from itching<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a> and <a href="/facts/Nettle_rash/zMkVo9qL">nettle rash</a> to <a href="/facts/Nausea/dyhkcbeD">nausea</a>, <a href="/facts/Hypotension/BhrdVVRS">hypotension</a>, and in rare cases <a href="/facts/Anaphylactic_shock/F9IDQxeL">anaphylactic shock</a>; it is therefore not recommended in those countries for children. </p> <h2 id="references">References</h2> <ol> <li id="fn:1"><p>Gessner, Thomas; Mayer, Udo (2000). "Triarylmethane and Diarylmethane Dyes". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a27_179. ISBN 978-3-527-30673-2. <a href="978-3-527-30673-2" target="_blank">978-3-527-30673-2</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> <li id="fn:2"><p>Erratum - 44 (4): 649 - The Journal of Nuclear Medicine <a href="http://jnm.snmjournals.org/cgi/content/full/44/4/649" target="_blank">http://jnm.snmjournals.org/cgi/content/full/44/4/649</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li> <li id="fn:3"><p>Sabnis, R. W. (2008). "Patent Blue V". Handbook of Acid–Base Indicators. CRC Press. pp. 295–297. ISBN 9780849382185. <a href="9780849382185" target="_blank">9780849382185</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li> <li id="fn:4"><p>Yoe, John H.; Boyd, George R. (1939). "Patent blue V as a pH and redox indicator". Ind. Eng. Chem. Anal. Ed. 11 (9): 492–493. doi:10.1021/ac50137a008. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li> <li id="fn:5"><p>L. Barthelmes, A. Goyal, R.G. Newcombe, F. McNeill, R.E. Mansel, Adverse reactions to patent blue V dye – The NEW START and ALMANAC experience, European Journal of Surgical Oncology (EJSO), Volume 36, Issue 4, April 2010, Pages 399-403, doi:10.1016/j.ejso.2009.10.007. <a href="//doi.org/10.1016/j.ejso.2009.10.007" target="_blank">//doi.org/10.1016/j.ejso.2009.10.007</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li> </ol>