A procedure which permits the slmultaneous determlnatlon of six major and minor elements (AI, Fe, Ca, Mg, Na, P) and elght trace elements (Be, Co, Cu, Mn, Ni, Pb, V, Zn) In near-shore marlne sedlments by inductively coupled plasma atomlc emlsslon spectrometry Is descrlbed. Dlsolutlon of the samples Is achleved wlth a mlxture of nltrlc, perchlorlc, and hydrofluorlc aclds In sealed Teflon vessels. Accurate callbratlon for all elements can be achleved with slmple aqueous standards, provlded that proper correctlon for varlous spectroscoplc interferences Is made. The accuracy of the method has been conflrmed by analysis of two marlne sedlment reference materials, MESS-1 and BCSS-1, recently produced In these laboratories. The method was not sultable for determlnatlon of As, Cd, and Mo in these materlals because of Inadequate sensitivity nor for Cr and ll because of Incomplete dlssolutlon.The precision, speed, and sensitivity of inductively coupled plasma atomic emission spectrometry (ICP-AES), as well as its remarkably low susceptibility to concomitant interferences, have led to rapid acceptance of this relatively new technique by geochemists and environmental scientists. At least at present, accurate ICP-AES analyses of geological materials require dissolution of the samples; whether or not complete dissolution is necessary depends on the elements to be determined. The choice of an appropriate dissolution procedure is also complicated by the temptation, on the one hand, to dilute the original sample as little as possible so that the maximum number of trace elements can be determined, and, on the other hand, the desire to avoid dissolved solids concentrations greater than 1 to 2% in the solution presented to the ICP. Fortunately, the sensitivity of ICP-AES permits the direct determination of many trace elements in geological materials even when the dissolution procedure involves a dilution of 100-fold or more. Accurate results are obtained, however, only if proper attention is paid to a variety of spectroscopic interferences which can arise when trace elements are determined in the presence of much higher concentrations of iron, aluminum, calcium, magnesium, and titanium.Recently, as part of the National Research Council of Canada Marine Analytical Chemistry Standards Program, this laboratory undertook production of two near-shore marine sediment reference materials, with the acronyms MESS-1 and BCSS-1, with reliable results for about 25 major, minor, and trace elements. ICP-AES played an important role in this project. This report is a detailed description of a procedure which permitted accurate direct determination of six major and minor constituents and eight trace metals in these sediments. It will be seen that the method of sample dissolution has a major impact on the scope of the subsequent multielement determinations by ICP-AES.The dissolution of geological materials can be accomplished by a variety of techniques which fall into two general categories: acid digestion and fusion (1). Previous studies (2-5) invol...
Methodology has been developed to separate nano-particles of amorphous material from Syncrude fine tailings. Both, separated finer solids and residual coarser solids, were characterized by elemental analysis, X-ray powder diffraction, XPS, SEM, infrared spectroscopy, solid-state NMR, density, and surface area measurements. Based on the results of infrared and X-ray diffraction, the amorphous minerals identified in finer solids included allophanes, halloysite, ferrihydrite, and amorphous silica. The finer fraction also contained some crystalline material consisting of muscovite and traces of quartz. The residual coarser solids consisted mostly of quartz, muscovite, and kaolinite. #
Toxicity (extreme weakness, body temperature drop, cyanosis, some slow deaths) in test mice, upon intraperitoneal injection of standardmethod paralytic shellfish poison (PSP) extracts of some PSP-free oysters, is consistent with the relatively high levels of zinc in these extracts. As a rough guideline, the threshold for a toxic response corresponds to a drained tissue zinc level of over 900 μg/g. The identification of zinc as the substance responsible has been supported by inducing toxicity in control extracts by spiking with nontoxic levels of zinc, and by eliminating toxicity from toxic extracts by chemical removal (precipitation, ion exchange) of metals.
A GC-ICP-MS method based on extraction and alkylation of butyltins with sodium tetraethylborate was used to quantitatively assess the fate of these analytes in solutions and sediments following exposure to gamma-irradiation. The effects of a 2.5 Mrad sterilization dose on three butyltin species in both methanolic calibration solutions and in sediment matrices were investigated. Although significant losses of tributyltin (TBT, 90%), dibutyltin (DBT, 100%) and monobutyltin (MBT, 80%) were detected in standard solutions prepared in methanol following gamma-irradiation, no species inter-conversion occurred. Some degradation of TBT (38%) and DBT (32%) but no significant change in MBT content was found using a spiked sediment CRM HISS-1. Conversion DBT to MBT in spiked HISS-1 was deduced. Much smaller degradation of TBT (16% loss) and 10% loss of DBT by conversion to MBT (14% gain) was registered using a sediment blend of PACS-2 and HISS-1 (SOPH). Despite some initial losses of TBT and DBT due to irradiation, better than 2% RSD in both TBT and DBT concentrations measured in twelve different bottles of blended sediment SOPH were obtained, indicating the material may be considered homogeneous for these analytes. Results from a long-term five-year stability study of PACS-2 show that all three butyltins are stable during storage at 4 degrees C followed with 2.5 Mrad minimum dose of gamma-irradiation sterilization treatment.
The determination of Cr in National Research Council of Canada Marine Sediment Reference Material BCSS-1 is addressed. Mixed acid digestions utilizing HF, HClO(4) and HNO(3) were investigated. Single microwave assisted digestions in closed vessels at medium pressures (8 bar) were inappropriate (80% recovery). Double digestion at moderate pressure and digestions at high pressure (70 bar) or lengthy open-beaker hot plate dissolutions resulted in 93+/-5% recovery of certified Cr content. Flame atomic absorption and inductively coupled plasma atomic emission spectrometry were used for quantitation. In all cases, the method of standard additions was necessary to eliminate the approximately 10% enhancement in re- sponce relative to unmatched standards. Compared to a certified content of 123+/-7 microg/g (mean and standard deviation), values of 116+/-6 were obtained using an open beaker digestion; 114+/-5 using a double microwave digestion at 8 bar; 113+/-2 for microwave digestion at high pressure and 111+/-4 at high pressure (81 bar) with triple microwave digestion in a Parr bomb. No acid dissolution procedure is adequate for Cr in this sample although recovery of total Cr is complete from National Institute of Standards and Technology Buffalo River Sediment (SRM 2704).
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