Development of an automated on-line purification HPLC single cell-ICP-MS approach for fast diatom analysis

• Published in: Analytica chimica acta Vol. 1077; pp. 87 - 94
• Main Authors: Au, Marcus von der, Schwinn, Max, Kuhlmeier, Katharina, Büchel, Claudia, Meermann, Björn
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 24.10.2019; Elsevier BV
• Subjects: Automated matrix removal; Automation; Deionization; Ecological effects; Ecotoxicological testing method development; Ecotoxicology; Fully automated single cell ICP-MS; High-performance liquid chromatography; Liquid chromatography; Magnesium; On-line systems; Plankton; Pretreatment; Purification; Sample preparation; Single diatom analysis; Automated matrix removal; Fully automated single cell ICP-MS; Ecotoxicological testing method development; Single diatom analysis
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2019.05.045

The most challenging part in performing a single cell ICP-MS (sc-ICP-MS) approach is the sample preparation, in particular the reduction of the ionic background. This step is, in many cases, time-consuming and required for each sample separately. Furthermore, sc-ICP-MS measurements are mostly carried out “manually”, given the fact that present systems are not allowing for an automated change of samples. Thus, within this work, we developed an approach based on a HPLC system coupled on-line with sc-ICP-MS via a set of switching valves as well as an in-line filter for automated cell washing. This set-up enables the ionic background removal as well as analysis of single cells completely automated without any manual sample pretreatment. Our approach was applied for the analysis of the single celled diatom species Cyclotella meneghiniana, a marine diatom species, on the basis of 24Mg and facilitates testing in 11 min per sample, requiring only around 10,000 cells in a volume of 10 μL and approx. 10 mL of a 5% MeOH/95% deionized water (v/v) mixture. Even at extremely saline culturing media concentrations (up to 1000 mg L−1 magnesium) our on-line approach worked sufficiently allowing for distinction of ionic and particulate fractions. Furthermore, a set of diatom samples was analyzed completely automated without the need for changing samples manually. So, utilizing this approach enables analyzing a high quantity of samples in a short time and therefore in future the investigation of ecotoxicological effects is simplified for example in terms of metal accumulation by taking biovariability into account. [Display omitted] •An approach based on HPLC on-line with single cell ICP-MS via switching valves and in-line filter for automated cell washing.•Automated ionic background removal and analysis of single cells (Cyclotella meneghiniana) without manual sample pretreatment.•High throughput analysis enables automated ecotox. testing in the future.