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<export-example>
  <doc>
    <id>52470</id>
    <completedYear/>
    <publishedYear>2021</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst>6019</pageFirst>
    <pageLast>6024</pageLast>
    <pageNumber/>
    <edition/>
    <issue>15</issue>
    <volume>93</volume>
    <type>article</type>
    <publisherName>ACS</publisherName>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>1</belongsToBibliography>
    <completedDate>--</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Quantitative Analysis of Pharmaceutical Drugs Using a Combination of Acoustic Levitation and High Resolution Mass Spectrometry</title>
    <abstract language="eng">A combination of acoustic levitation, laser vaporization, and atmospheric pressure chemical ionization mass spectrometry (APCI-MS) is presented in this study that enabled sensitive analysis of pharmaceutical drugs from an aqueous sample matrix. An unfocused pulsed infrared laser provided contactless sample desorption from the droplets trapped inside an acoustic levitator by activation of the OH stretching band of aqueous and alcoholic solvents. Subsequent atmospheric pressure chemical ionization was used between the levitated droplet and the mass spectrometer for postionization. In this setup, the unfocused laser gently desorbed the analytes by applying very mild repulsive forces. Detailed plume formation studies by temporally resolved schlieren experiments were used to characterize the liquid gas transition in this process. In addition, the role of different additives and solvent composition was examined during the ionization process. The analytical application of the technique and the proof-of-concept for quantitative analysis were demonstrated by the determination of selected pharmaceutical drugs in aqueous matrix with limits of quantification at the lower nanomolar level and a linear dynamic range of 3–4 orders of magnitude.</abstract>
    <parentTitle language="eng">Analytical Chemistry</parentTitle>
    <identifier type="doi">10.1021/acs.analchem.1c00762</identifier>
    <enrichment key="opus.source">publish</enrichment>
    <enrichment key="date_peer_review">21.04.2021</enrichment>
    <author>S. van Wasen</author>
    <author>Yi You</author>
    <author>S. Beck</author>
    <author>Jens Riedel</author>
    <author>D. Volmer</author>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Atmospheric Pressure Chemical Ionization</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Ultrasonic Levitation</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Mass Spectrometry</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Laser Desorption</value>
    </subject>
    <collection role="ddc" number="543">Analytische Chemie</collection>
    <collection role="institutes" number="">P Präsident</collection>
    <collection role="institutes" number="">1 Analytische Chemie; Referenzmaterialien</collection>
    <collection role="institutes" number="">1.3 Instrumentelle Analytik</collection>
    <collection role="themenfelder" number="">Chemie und Prozesstechnik</collection>
    <collection role="literaturgattung" number="">Verlagsliteratur</collection>
    <collection role="fulltextaccess" number="">Datei im Netzwerk der BAM verfügbar ("Closed Access")</collection>
    <collection role="institutes" number="">PST Präsidiale Stabsstelle</collection>
  </doc>
  <doc>
    <id>53028</id>
    <completedYear/>
    <publishedYear>2021</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst>10022</pageFirst>
    <pageLast>10030</pageLast>
    <pageNumber/>
    <edition/>
    <issue>29</issue>
    <volume>93</volume>
    <type>article</type>
    <publisherName>American Chemical Society</publisherName>
    <publisherPlace>Washington, DC, USA</publisherPlace>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>1</belongsToBibliography>
    <completedDate>--</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">High-Resolution Atomic Absorption Spectrometry Combined With Machine Learning Data Processing for Isotope Amount Ratio Analysis of Lithium</title>
    <abstract language="eng">An alternative method for lithium isotope amount ratio analysis based on a combination of high-resolution atomic absorption spectrometry and spectral data analysis by machine learning (ML) is proposed herein. It is based on the well-known isotope shift of approximately 15 pm for the electronic transition 22P←22S at around the wavelength of 670.8 nm, which can be measured by the state-of-the-art high-resolution continuum source graphite furnace atomic absorption spectrometry. For isotope amount ratio analysis, a scalable tree boosting ML algorithm (XGBoost) was employed and calibrated using a set of samples with 6Li isotope amount fractions, ranging from 0.06 to 0.99 mol mol–1, previously determined by a multicollector inductively coupled plasma mass spectrometer (MC-ICP-MS). The calibration ML model was validated with two certified reference materials (LSVEC and IRMM-016). The procedure was applied toward the isotope amount ratio determination of a set of stock chemicals (Li2CO3, LiNO3, LiCl, and LiOH) and a BAM candidate reference material NMC111 (LiNi1/3Mn1/3Co1/3O2), a Li-battery cathode material. The results of these determinations were compared with those obtained by MC-ICP-MS and found to be metrologically comparable and compatible. The residual bias was −1.8‰, and the precision obtained ranged from 1.9 to 6.2‰. This precision was sufficient to resolve naturally occurring variations, as demonstrated for samples ranging from approximately −3 to +15‰. To assess its suitability to technical applications, the NMC111 cathode candidate reference material was analyzed using high-resolution continuum source atomic absorption spectrometry with and without matrix purification. The results obtained were metrologically compatible with each other.</abstract>
    <parentTitle language="eng">Analytical Chemistry</parentTitle>
    <identifier type="issn">1520-6882</identifier>
    <identifier type="doi">10.1021/acs.analchem.1c00206</identifier>
    <enrichment key="opus.source">publish</enrichment>
    <enrichment key="date_peer_review">28.07.2021</enrichment>
    <author>Alexander Winckelmann</author>
    <author>S. Nowak</author>
    <author>Silke Richter</author>
    <author>Sebastian Recknagel</author>
    <author>Jens Riedel</author>
    <author>Jochen Vogl</author>
    <author>Ulrich Panne</author>
    <author>Carlos Enrique Abad Andrade</author>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Lithium</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Isotope</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Machine learning</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Algorithms</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Reference material</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>AAS</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Atomic Absorption Spectrometry</value>
    </subject>
    <collection role="ddc" number="543">Analytische Chemie</collection>
    <collection role="ddc" number="621">Angewandte Physik</collection>
    <collection role="institutes" number="">P Präsident</collection>
    <collection role="institutes" number="">1 Analytische Chemie; Referenzmaterialien</collection>
    <collection role="institutes" number="">1.1 Anorganische Spurenanalytik</collection>
    <collection role="institutes" number="">1.3 Instrumentelle Analytik</collection>
    <collection role="institutes" number="">1.6 Anorganische Referenzmaterialien und Gasanalytik</collection>
    <collection role="institutes" number="">S Qualitätsinfrastruktur</collection>
    <collection role="institutes" number="">S.1 Qualität im Prüfwesen</collection>
    <collection role="themenfelder" number="">Energie</collection>
    <collection role="themenfelder" number="">Elektrische Energiespeicher und -umwandlung</collection>
    <collection role="themenfelder" number="">Chemie und Prozesstechnik</collection>
    <collection role="themenfelder" number="">Chemische Charakterisierung und Spurenanalytik</collection>
    <collection role="literaturgattung" number="">Verlagsliteratur</collection>
    <collection role="fulltextaccess" number="">Datei im Netzwerk der BAM verfügbar ("Closed Access")</collection>
    <collection role="unnumberedseries" number="">Wissenschaftliche Artikel der BAM</collection>
    <collection role="institutes" number="">P.0 Präsident und andere</collection>
    <collection role="institutes" number="">PST Präsidiale Stabsstelle</collection>
    <thesisPublisher>Bundesanstalt für Materialforschung und -prüfung (BAM)</thesisPublisher>
  </doc>
</export-example>
