Solid sampling-electrothermal vaporization-inductively coupled plasma mass spectrometry for the direct determination of traces of boron in biological materials using isotope dilution for calibration

Abstract

In this work, the possibilities of electrothermal vaporization-inductively coupled plasma mass spectrometry for the direct determination of B in biological samples have been critically evaluated, the goal always being to develop a fast and robust method that could be applied to different samples without significant modi. cations to the working protocol. Four reference materials of different nature (NIST SRM 1570a Trace Elements in Spinach Leaves, NIST SRM 1573a Tomato leaves, NIST SRM 1548a Typical Diet and BCR CRM 281 Rye Grass) were selected for this study. The importance of the use of NH4F center dot HF as chemical modi. er for this element was demonstrated. By using this modi. er, it was observed that the analyte can be vaporized and transported to the ICP in a more efficient way even at low vaporization temperatures (from 1000 degrees C onwards), resulting in a sensitivity increase (of a factor of approximately 10 compared with the vaporization in the absence of any modi. er) while minimizing memory effects and carbon co-vaporization. The temperature program was adapted to permit the effecient use of this modi. er when direct analysis of solid samples was intended. However, although well-defined B signal profiles could be attained also for the solid samples, evidence of signal suppression was observed. Under these conditions, the use of external calibration with aqueous standards would result in underestimated results (40-60% of the expected values). It was demonstrated that the use of isotope dilution can satisfactorily correct for these suppression effects, allowing accurate results to be obtained for all the samples under investigation. The most relevant figures of merit of the method finally developed are: RSD values ranging from 7 to 9%, a detection limit of 8 ng g(-1), a sample throughput of 20 - 25 min per determination and a sample consumption of approximately 5 mg per determination

Determination of palladium, platinum and rhodium in used automobile catalysts and active pharmaceutical ingredients using high-resolution continuum source graphite furnace atomic absorption spectrometry and direct solid sample analysis

“…As can be seen, the best results were obtained upon the addition of NH 4 F·HF. This reagent shows a suitable volatility for GFAAS analysis since it is stable during the drying step, and only later (T N 120°C) decomposes liberating HF [45,46]. It is the only modifier that permits obtaining a unimodal well-defined signal profile for Pd that returns to the baseline after 10 s. Moreover, the integrated absorbance obtained is 30% higher than the value observed without modifier, and also higher than the values obtained for the other modifiers (see Fig.…”

Chlorine isotope determination via the monitoring of the AlCl molecule by high-resolution continuum source graphite furnace molecular absorption spectrometry – a case study

“…For the latter approach, a calibration curve was prepared with 5 points ranging from 1 to 10 mg L -1 . 43 The LOD was estimated to be of 0.25 mg L -1 . The results obtained for the samples are shown in Table 4.…”

Determination of toxic trace impurities in titanium dioxide by solid sampling-electrothermal vaporization-inductively coupled plasma mass spectrometry

“…1, the impact of the TiO + interference on the signal at a mass-to-charge ratio of 64 is much higher than that observed at a mass-to-charge ratio of 66, as the abundance of the ion interfering at m/z 64 ( 48 Ti 16 O + ) is much higher than that of the ion at m/z 66 ( 50 Ti 18 O + ). As a consequence, a dramatic increase of the 64 Zn + / 66 Zn + ratio, by factors much higher than those expected taking into account the typical uncertainty values observed for isotope ratio monitoring with SS-ETV-ICPMS (typically below 3% 28 ), is seen when matrix covaporization occurs. This fact allowed to detect and discard some biased measurements (in practice, those values differing by more than 3% from the median of all the values measured during the session were discarded).…”