Improved Sampling Design for Depth Profile Analysis of Marine Sediments Using Sector-Field – Inductively Coupled Plasma – Mass Spectrometry (SF-ICP-MS)
Geochemical characterization of marine sediments requires analytical techniques able to provide high sensitivity and are insusceptible to matrix interferences that are supported by using simple to use sampling devices that ensure minimal disturbance to the samples. Well-established atomic spectroscopy techniques show capabilities for depth profiling but with limited sensitivity for the determination of relevant trace elements. Therefore, in this work, an improved analytical approach is developed based on the use of an in-house versatile device for sampling layers of bottom sediments with insignificant composition disturbance, improved depth resolution, sample volumes larger than 0.1 m3, and to a sampling depth of 10 m. The analysis was performed by sector-field – inductively coupled plasma – mass spectrometry (SF-ICP-MS). Precise and interference-free quantification of a range of heavy metals was attained, with recovery values from 89 to 109% for the marine sediment CRM IAEA-158, repeatability from 3 to 5%, intermediate precision below 6%, and limits of detection from 0.1 to 160 ng/g. The SF-ICP-MS method was applied for sensitive profiling of in-depth distributions of minor and trace metals, as well as sulfur, in sediments collected from the continental shelf of the East Siberian Sea, which are of great interest for deciphering the underlying geochemical processes. There is extensive sulfide accumulation with associated reducing conditions, specifically affecting the vertical profiles of certain metals, including manganese, vanadium, and uranium.
