Laser induced breakdown spectroscopy for heavy metal detection in a sand matrix

© The Author(s), 2016. This is the author's version of the work and is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Spectrochimica Acta Part B: Atomic Spectroscopy 125 (2016):177-183, doi:10.1016/j.sab.2016.10.001.Sediments in many locations, including harbors and coastal areas, can become contaminated and polluted, for example, from anthropogenic inputs, shipping, human activities, and poor waste management. Sampling followed by laboratory analysis has been the traditional methodology for such analysis. In order to develop rapid methodologies for eld analysis of sediment samples, especially for metals analyses, we look to Laser Induced Breakdown Spectroscopy as an option. Here through laboratory experiments, we demonstrate that dry sand samples can be rapidly analyzed for the detection of the heavy metals chromium, zinc, lead, and copper. We also demonstrate that cadmium and nickel are detectable in sand matrices at high concentrations.This work is supported by funding from the National Science Foundation (OCE-RIG: 1322704) and the Woods Hole Oceanographic Institution by The Penzance Endowed Fund in Support of Assistant Scientists and The Reuben F. and Elizabeth B. Richards Endowed Fund in Support of Scienti c Sta .2018-10-0

In Situ Sensor Technology for Simultaneous Spectrophotometric Measurements of Seawater Total Dissolved Inorganic Carbon and pH

A new, in situ sensing system, Channelized Optical System (CHANOS), was recently developed to make high-resolution, simultaneous measurements of total dissolved inorganic carbon (DIC) and pH in seawater. Measurements made by this single, compact sensor can fully characterize the marine carbonate system. The system has a modular design to accommodate two independent, but similar measurement channels for DIC and pH. Both are based on spectrophotometric detection of hydrogen ion concentrations. The pH channel uses a flow-through, sample-indicator mixing design to achieve near instantaneous measurements. The DIC channel adapts a recently developed spectrophotometric method to achieve flow-through CO₂ equilibration between an acidified sample and an indicator solution with a response time of only ∼90 s. During laboratory and in situ testing, CHANOS achieved a precision of ±0.0010 and ±2.5 μmol kg^–1 for pH and DIC, respectively. In situ comparison tests indicated that the accuracies of the pH and DIC channels over a three-week time-series deployment were ±0.0024 and ±4.1 μmol kg^–1, respectively. This study demonstrates that CHANOS can make in situ, climatology-quality measurements by measuring two desirable CO₂ parameters, and is capable of resolving the CO₂ system in dynamic marine environments