A simple dilute-and-shoot approach for the determination of ultra-trace levels of arsenic in biological fluids via ICP-MS using CH3F/He as a reaction gas

The performance of a mixture of CH3F/He (1/9) as a reaction gas for the determination of As in biological fluids using a quadrupole ICP-MS instrument has been explored. A simple (dilute-and-shoot) interference-free method has been developed to quantify As concentrations at trace and ultra-trace levels in matrices with a high Cl content. As+ reacts with CH3F (through CH3F addition, followed by HF elimination) with high efficiency forming AsCH2 + as the primary reaction product, which can be monitored at a mass-to-charge ratio of 89, free from the Cl-based interferents (e.g., 40Ar35Cl+ and 40Ca35Cl+) that hamper the monitoring of 75As+. Matrix effects are overcome by the use of Te as an internal standard and the addition of 3% v/v ethanol to all samples and calibration standard solutions. The method presented was validated by analysing a set of reference materials (blood, serum and urine) and by assessing As recovery from a set of real blood samples. With this method, the limit of detection was calculated to be 0.8 ng L-1 As, favourably comparable to the vast majority of values reported in the literature, even with those obtained using more sophisticated sector-field instrumentation

Emerging CO2 capture systems

In 2005, the IPCC SRCCS recognized the large potential for developing and scaling up a wide range of emerging CO2 capture technologies that promised to deliver lower energy penalties and cost. These included new energy conversion technologies such as chemical looping and novel capture systems based on the use of solid sorbents or membrane-based separation systems. In the last 10 years, a substantial body of scientific and technical literature on these topics has been produced from a large number of R&D projects worldwide, trying to demonstrate these concepts at increasing pilot scales, test and model the performance of key components at bench scale, investigate and develop improved functional materials, optimize the full process schemes with a view to a wide range of industrial applications, and to carry out more rigorous cost studies etc. This paper presents a general and critical review of the state of the art of these emerging CO2 capture technologies paying special attention to specific process routes that have undergone a substantial increase in technical readiness level toward the large scales required by any CO2 capture system

Interference-free determination of ultra-trace concentrations of arsenic and selenium using methyl fluoride as a reaction gas in ICP-MS/MS

Interference-free conditions, allowing straightforward As and Se determination, can be obtained by using CH3F (a mixture of 10 % CH3F and 90 % He) as a reaction gas in tandem ICP-mass spectrometry (ICP-MS/MS). Both target elements react via CH3F addition and subsequent HF elimination, rendering AsCH2 (+) and SeCH2 (+) the respective favored reaction product ions. Instrumental limits of detection were 0.2 ng L-1 for As and below 10 ng L-1 for Se, using either Se-77, Se-78, or Se-80. Neither addition of carbon to the solutions, nor admixing of additional He into the octopole reaction cell resulted in a further improvement of the LoDs, despite the increase in analyte signal intensity. By using synthetic matrices, containing elements giving rise to ions interfering at either the original mass-to-charge ratios or those of the reaction products, absence of spectral overlap could be demonstrated. This conclusion was corroborated by successful As and Se determination in a collection of reference materials from plant, animal, or environmental origin, displaying a considerable range of As and Se contents. These accurate results were obtained via external calibration using Te as an internal standard. The high efficiency reaction between As and CH3F and the possibility to use the major isotope of Se provides enhanced detection power versus other techniques, such as sector-field ICP-mass spectrometry, while the possibility to monitor at least three Se isotopes interference-free also enables isotopic analysis