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<article article-type="research-article" dtd-version="1.3" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xml:lang="en"><front><journal-meta><journal-id journal-id-type="publisher-id">epilepsia</journal-id><journal-title-group><journal-title xml:lang="en">Epilepsy and paroxysmal conditions</journal-title><trans-title-group xml:lang="ru"><trans-title>Эпилепсия и пароксизмальные состояния</trans-title></trans-title-group></journal-title-group><issn pub-type="ppub">2077-8333</issn><issn pub-type="epub">2311-4088</issn><publisher><publisher-name>IRBIS LLC</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="doi">10.17749/2077-8333/epi.par.con.2026.275</article-id><article-id custom-type="elpub" pub-id-type="custom">epilepsia-1346</article-id><article-categories><subj-group subj-group-type="heading"><subject>Research Article</subject></subj-group><subj-group subj-group-type="section-heading" xml:lang="en"><subject>ORIGINAL ARTICLES</subject></subj-group><subj-group subj-group-type="section-heading" xml:lang="ru"><subject>ОРИГИНАЛЬНЫЕ СТАТЬИ</subject></subj-group></article-categories><title-group><article-title>Gas chromatography-mass spectrometry for quantitating valproic acid in blood serum</article-title><trans-title-group xml:lang="ru"><trans-title>Определение концентрации вальпроевой кислоты в сыворотке крови методом газовой хроматографии с масс-спектрометрическим детектированием</trans-title></trans-title-group></title-group><contrib-group><contrib contrib-type="author" corresp="yes"><contrib-id contrib-id-type="orcid">https://orcid.org/0009-0004-7718-2639</contrib-id><name-alternatives><name name-style="eastern" xml:lang="ru"><surname>Банникова</surname><given-names>В. М.</given-names></name><name name-style="western" xml:lang="en"><surname>Bannikova</surname><given-names>V. M.</given-names></name></name-alternatives><bio xml:lang="ru"><p>Банникова Василиса Михайловна</p><p>Ореховый б-р, д. 49, корп. 1, Москва 115580</p></bio><bio xml:lang="en"><p>Vasilisa M. Bannikova </p><p>49 corp. 1 Orekhovyy Blvd, Moscow 115580</p><p> </p></bio><xref ref-type="aff" rid="aff-1"/></contrib><contrib contrib-type="author" corresp="yes"><contrib-id contrib-id-type="orcid">https://orcid.org/0000-0003-4434-8415</contrib-id><name-alternatives><name name-style="eastern" xml:lang="ru"><surname>Сеидкулиева</surname><given-names>А. А.</given-names></name><name name-style="western" xml:lang="en"><surname>Seidkulieva</surname><given-names>A. A.</given-names></name></name-alternatives><bio xml:lang="ru"><p>Сеидкулиева Адамиана Аманмамедовна, к.м.н.</p><p>WoS ResearcherID: ABF-4016-2021. Scopus Author ID: 57226686283</p><p>Ореховый б-р, д. 49, корп. 1, Москва 115580</p></bio><bio xml:lang="en"><p>Adamiana A. Seidkulieva, PhD </p><p>WoS ResearcherID: ABF-4016-2021. Scopus Author ID: 57226686283</p><p>49 corp. 1 Orekhovyy Blvd, Moscow 115580</p></bio><xref ref-type="aff" rid="aff-1"/></contrib><contrib contrib-type="author" corresp="yes"><contrib-id contrib-id-type="orcid">https://orcid.org/0000-0003-1592-759X</contrib-id><name-alternatives><name name-style="eastern" xml:lang="ru"><surname>Панов</surname><given-names>Ю. М.</given-names></name><name name-style="western" xml:lang="en"><surname>Panov</surname><given-names>Yu. M.</given-names></name></name-alternatives><bio xml:lang="ru"><p>Панов Юрий Михайлович</p><p>Scopus Author ID: 57210412012</p><p>Ореховый б-р, д. 49, корп. 1, Москва 115580</p></bio><bio xml:lang="en"><p>Yuri M. Panov </p><p>Scopus Author ID: 57210412012</p><p>49 corp. 1 Orekhovyy Blvd, Moscow 115580</p></bio><email xlink:type="simple">PanovYM94@yandex.ru</email><xref ref-type="aff" rid="aff-1"/></contrib><contrib contrib-type="author" corresp="yes"><contrib-id contrib-id-type="orcid">https://orcid.org/0000-0003-4503-7168</contrib-id><name-alternatives><name name-style="eastern" xml:lang="ru"><surname>Каргин</surname><given-names>И. Д.</given-names></name><name name-style="western" xml:lang="en"><surname>Kargin</surname><given-names>I. D.</given-names></name></name-alternatives><bio xml:lang="ru"><p>Каргин Иван Денисович</p><p>Ореховый б-р, д. 49, корп. 1, Москва 115580</p></bio><bio xml:lang="en"><p>Ivan D. Kargin </p><p>49 corp. 1 Orekhovyy Blvd, Moscow 115580</p></bio><xref ref-type="aff" rid="aff-1"/></contrib><contrib contrib-type="author" corresp="yes"><contrib-id contrib-id-type="orcid">https://orcid.org/0000-0001-8555-5969</contrib-id><name-alternatives><name name-style="eastern" xml:lang="ru"><surname>Бочков</surname><given-names>П. О.</given-names></name><name name-style="western" xml:lang="en"><surname>Bochkov</surname><given-names>P. O.</given-names></name></name-alternatives><bio xml:lang="ru"><p>Бочков Павел Олегович, к.б.н.</p><p>Ореховый б-р, д. 49, корп. 1, Москва 115580</p></bio><bio xml:lang="en"><p>Pavel O. Bochkov, PhD</p><p>49 corp. 1 Orekhovyy Blvd, Moscow 115580</p></bio><xref ref-type="aff" rid="aff-1"/></contrib></contrib-group><aff-alternatives id="aff-1"><aff xml:lang="ru"><institution>Государственное бюджетное учреждение здравоохранения г. Москвы «Московский научно-практический центр лабораторных исследований Департамента здравоохранения г. Москвы»</institution><country>Россия</country></aff><aff xml:lang="en"><institution>Moscow Scientific and Practical Center for Laboratory Research</institution><country>Russian Federation</country></aff></aff-alternatives><pub-date pub-type="collection"><year>2026</year></pub-date><pub-date pub-type="epub"><day>03</day><month>08</month><year>2026</year></pub-date><volume>18</volume><issue>2</issue><elocation-id>122–133</elocation-id><permissions><copyright-statement>Copyright &amp;#x00A9; Bannikova V.M., Seidkulieva A.A., Panov Y.M., Kargin I.D., Bochkov P.O., 2026</copyright-statement><copyright-year>2026</copyright-year><copyright-holder xml:lang="ru">Банникова В.М., Сеидкулиева А.А., Панов Ю.М., Каргин И.Д., Бочков П.О.</copyright-holder><copyright-holder xml:lang="en">Bannikova V.M., Seidkulieva A.A., Panov Y.M., Kargin I.D., Bochkov P.O.</copyright-holder><license xml:lang="ru" license-type="creative-commons-attribution" xlink:href="https://creativecommons.org/licenses/by/4.0/" xlink:type="simple"><license-p>Данная работа распространяется под лицензией Creative Commons Attribution 4.0.</license-p></license><license xml:lang="en" license-type="creative-commons-attribution" xlink:href="https://creativecommons.org/licenses/by/4.0/" xlink:type="simple"><license-p>This work is licensed under a Creative Commons Attribution 4.0 License.</license-p></license></permissions><self-uri xlink:href="https://www.epilepsia.su/jour/article/view/1346">https://www.epilepsia.su/jour/article/view/1346</self-uri><abstract><sec><title>Background</title><p>Background. Generating a sensitive and selective method to quantitate valproic acid (VPA) for therapeutic drug monitoring, using as low as 50 µl of blood serum sample, is highly relevant for pediatric patients, for whom biomaterial collection can be challenging.</p></sec><sec><title>Objective</title><p>Objective: To develop and validate a method to quantitate VPA level in blood serum using gas chromatography-mass spectrometry (GC-MS) without derivatization, added with phenylacetic acid as an internal standard (IS), for therapeutic drug monitoring, and to comparatively analyze results obtained using developed method and immunochemical approach.</p></sec><sec><title>Material and methods</title><p>Material and methods. Extraction of VPA and IS was performed using liquid-liquid extraction with ethyl acetate, after preacidification of blood serum sample with 1 M hydrochloric acid. The lower limit of quantification was 5 µg/ml, with calibration range 5–200 µg/ml. The study employed a GC-MS system consisting of Agilent 5977B SQ single quadrupole MS-detector equipped with a high-efficiency source for electron impact ionization, and Agilent 7890 gas chromatograph (both – Agilent Technologies, USA). Analytes were quantitated by using electron impact ionization in selected ion monitoring mode. For VPA, the characteristic fragment ion with mass-to-charge ratio (m/z) 102 was used, and for IS – most intense characteristic fragment ion with m/z 91. Chromatographic separation was carried out on HP-5MS Ultra Inert column (30 m × 250 µm × 0.25 µm) (Agilent Technologies, USA).</p></sec><sec><title>Results</title><p>Results. A comparative analysis of the results obtained in determining VPA level in blood serum samples using GC-MS and immunochemical method demonstrated a high degree of correlation, thereby verifying feasibility of the developed method for therapeutic drug monitoring.</p></sec><sec><title>Conclusion</title><p>Conclusion. The developed GC-MS method is characterized by high sensitivity and selectivity and can be recommended for introduction into clinical practice for therapeutic drug monitoring of VPA concentration as an alternative to immunochemical approach.</p></sec></abstract><trans-abstract xml:lang="ru"><sec><title>Актуальность</title><p>Актуальность. Создание чувствительного и селективного метода определения концентрации вальпроевой кислоты (ВК) для терапевтического лекарственного мониторинга с использованием для анализа всего 50 мкл сыворотки крови особенно актуально для детей, у которых взятие биоматериала может вызывать трудности.</p></sec><sec><title>Цель</title><p>Цель: разработка и валидация методики количественного определения ВК в сыворотке крови методом газовой хроматографии с масс-спектрометрией (ГХ-МС) без дериватизации с добавлением фенилуксусной кислоты в качестве внутреннего стандарта (ВС) для терапевтического лекарственного мониторинга, проведение сравнительного анализа результатов, полученных с помощью разработанного и иммунохимического методов.</p></sec><sec><title>Материал и методы</title><p>Материал и методы. Извлечение ВК и ВС проводили с помощью жидкостно-жидкостной экстракции этилацетатом с предварительным подкислением сыворотки крови 1 М раствором соляной кислоты. Нижний предел количественного определения составил 5 мкг/мл, диапазон концентраций – от 5 до 200 мкг/мл. В работе использовали систему ГХ-МС, состоящую из моноквадрупольного МС-детектора Agilent 5977B SQ, оснащенного высокоэффективным источником ионизации электронным ударом, и газового хроматографа Agilent 7890 (оба – Agilent Technologies, США). Количественное определение исследуемых веществ выполняли при ионизации электронным ударом с использованием режима сканирования «мониторинг выбранных ионов». Для ВК применяли характеристичный фрагментный ион с отношением массы к заряду (m/z) 102, для ВС – характеристичный фрагментный ион наибольшей интенсивности с m/z 91. Хроматографическое разделение осуществляли на колонке HP-5MS Ultra Inert 30 м × 250 мкм × 0,25 мкм (Agilent Technologies, США).</p></sec><sec><title>Результаты</title><p>Результаты. Сравнительный анализ результатов, полученных при определении содержания ВК в образцах сыворотки крови с помощью ГХ-МС и иммунохимического метода, продемонстрировал высокую степень корреляции. Показана пригодность разработанного метода для терапевтического лекарственного мониторинга.</p></sec><sec><title>Заключение</title><p>Заключение. Разработанная методика ГХ-МС характеризуется высокой чувствительностью и селективностью и может быть рекомендована для внедрения в клиническую практику в рамках терапевтического лекарственного мониторинга концентрации ВК как альтернатива иммунохимическому методу.</p></sec></trans-abstract><kwd-group xml:lang="ru"><kwd>пробоподготовка</kwd><kwd>жидкостно-жидкостная экстракция</kwd><kwd>валидация</kwd><kwd>газовая хроматография</kwd><kwd>масс-спектрометрия</kwd><kwd>вальпроевая кислота</kwd><kwd>терапевтический лекарственный мониторинг</kwd><kwd>эпилепсия</kwd></kwd-group><kwd-group xml:lang="en"><kwd>sample preparation</kwd><kwd>liquid-liquid extraction</kwd><kwd>validation</kwd><kwd>gas chromatography</kwd><kwd>mass spectrometry</kwd><kwd>valproic acid</kwd><kwd>therapeutic drug monitoring</kwd><kwd>epilepsy</kwd></kwd-group></article-meta></front><back><ref-list><title>References</title><ref id="cit1"><label>1</label><citation-alternatives><mixed-citation xml:lang="ru">Белоусов Ю.Б., Леонова М.В., Штейнберг Л.Л. и др. 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