Direct temperature-resolved mass spectrometry as a technique for the semi-quantitative analysis of marine particulate organic matter

To date, direct temperature-resolved mass spectrometry (DT-MS, a form of te mperature-resolved, in-source pyrolysis mass spectrometry) has generally be en used to provide qualitative views of the broad-band molecular-level char acteristics of complex organic samples. In this paper low voltage electron impact (EI+) DT-MS is used to provide semi-quantitative information on mole cular-level characteristics of marine particulate organic matter (POM) samp les. This class of samples is analytically challenging for two main reasons . Firstly, it is difficult to obtain representative data sets in which samp le sizes are sufficient for characterization. Secondly, marine organic matt er samples contain many identifiable compound classes in conjunction with a substantial percentage of as-of-yet uncharacterizable material. As a first step toward quantitation, DT-MS analysis of selected standards was used to determine relative response factors of common compound classes identified in marine organic matter. These response factors were then used to quantify the relative contribution of the compound classes in two natural POM sampl es. The potential of DT-MS as a quantitative technique was then further exp lored by comparing DT-MS determinations of particulate organic carbon to ch lorophyll ratios (POC/chl) in natural POM samples with the same ratios dete rmined by elemental analysis and liquid chromatography (HPLC), a technique currently employed by marine chemists. (C) 2000 Elsevier Science B.V. All r ights reserved.