Editing Scoville scale (section)

== Quantification by HPLC ==
[[Image:Red savina cropped.jpg|thumb|The [[Red Savina pepper]], a hot chili<ref name=":3">{{Cite book |last1=DeWitt |first1=Dave |last2=Bosland |first2=Paul W. |title=The Complete Chile Pepper Book |year=2009 |publisher=Timber Press |isbn=978-0-88192-920-1}}</ref>]]

Since the 1980s, spice heat has been assessed quantitatively by [[high-performance liquid chromatography]] (HPLC), which measures the concentration of heat-producing capsaicinoids, typically with capsaicin content as the main measure.<ref name="guzman" /><ref name=collins/> As stated in one review "the most reliable, rapid, and efficient method to identify and quantify capsaicinoids is HPLC; the results of which can be converted to Scoville heat units by multiplying the parts-per-million by 16."<ref name="guzman" />{{efn|name=fifteen-sixteen}}

HPLC method gives results in [[American Spice Trade Association]] 1985 "pungency units", which are defined as one part capsaicin equivalent per million parts [[dry matter|dried pepper mass]]. This "[[parts per million]] of heat" (ppmH) is found with the following calculation:<ref name="collins" /> 
<math display="block">\text{ppmH}  = \frac{\text{peak area}({\text{capsaicin})} + 0.82\cdot \text{peak area}(\text{dihydrocapsaicin)}}{\text{peak area}(\text{standard)}}</math>

Peak areas are calculated from HPLC traces of dry samples of the substance to be tested in 1 ml of [[acetonitrile]]. The standard used to calibrate the calculation is 1 gram of capsaicin. Scoville heat units are found by multiplying the ppmH value by a factor of 15.<ref name="collins" />{{Efn|name=fifteen-sixteen|Some sources such as Guzman<ref name="guzman" /> state a factor of 16 in line with the 16,000,000&nbsp;SHU figure of pure capsaicin. However, Guzman cites the Collins source.<ref name="collins" />  which clearly states 15 per ASTA.}}  By this definition of ppmH, spicy compounds other than the two most important capsaicinoids are ignored, despite the ability of HPLC to measure these other compounds at the same time.<ref name="collins" />