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<p>Many monoterpenes have at least two different stereochemical forms, and many biosynthetic pathways are known to favor one product over the other(s). A rapid method was developed and used in the determination of the (<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M1" display="inline" overflow="scroll" dspmath="mathml"><mrow><mo>-</mo><mo>/</mo><mo>+</mo></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="24pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="fd1d90efa33a7e7d00abf7e289ed82d6"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-15-4651-2022-ie00001.svg" width="24pt" height="14pt" src="amt-15-4651-2022-ie00001.png"/></svg:svg></span></span>)-enantiomeric distributions for <span class="inline-formula"><i>α</i></span>-pinene, <span class="inline-formula"><i>β</i></span>-pinene, camphene, limonene, and <span class="inline-formula"><i>β</i></span>-phellandrene as emitted by plant material from six conifer species. The six species included the two pine species <i>Pseudotsuga menziesii</i> and <i>Pinus ponderosa</i>, as well as the four cypress species <i>Chamaecyparis lawsoniana</i>, <i>Thuja plilcata</i>, <i>Juniperus chinensis</i>, and <i>Thuja occidentalis</i>. The method involved passive sampling adsorption–thermal desorption (ps-ATD). During sampling, the cartridge tube was placed in a 60 mL glass vial with plant material for 1 h. Sample analytes were thermally transferred to a chiral gas chromatography (GC) column. Detection was by mass spectrometry (MS). The six species exhibited different emission patterns for the five monoterpenes in the <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M5" display="inline" overflow="scroll" dspmath="mathml"><mrow><mo>-</mo><mo>/</mo><mo>+</mo></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="24pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="9c4ee3e6af5f82be9ca798c8fbbc9d8b"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-15-4651-2022-ie00002.svg" width="24pt" height="14pt" src="amt-15-4651-2022-ie00002.png"/></svg:svg></span></span> totals, although within a given species the distributions among the five monoterpenes were similar across multiple plants. <span class="inline-formula"><i>β</i></span>-pinene dominated in <i>P. menziesii</i> and <i>P. ponderosa</i>, and <span class="inline-formula"><i>α</i></span>-pinene dominated in <i>T. plicata</i> and <i>T. occidentalis</i>. The chiral separations revealed differences in the <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M8" display="inline" overflow="scroll" dspmath="mathml"><mrow><mo>-</mo><mo>/</mo><mo>+</mo></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="24pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="b81f85c36e7cb7bfcfede11682d769ca"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-15-4651-2022-ie00003.svg" width="24pt" height="14pt" src="amt-15-4651-2022-ie00003.png"/></svg:svg></span></span> enantiomeric distributions among the species. The (<span class="inline-formula">−</span>)-enantiomers of <span class="inline-formula"><i>α</i></span>-pinene and <span class="inline-formula"><i>β</i></span>-pinene dominated strongly in <i>P. menziesii</i> and <i>P. ponderosa</i>; the (<span class="inline-formula">−</span>)-enantiomer of <span class="inline-formula"><i>β</i></span>-phellandrene dominated in <i>C. lawsoniana</i>. The dependence of the method precision on percent enantiomer abundance is discussed.</p>