Nowadays, microwave-assisted procedures using closed vessels with thermal, chemical, and mechanical resistance are the state-of-the-art for efficient digestion of samples. Safety issues related to sample reactivity should be considered and analytical throughput is also a critical parameter. The choice of a specific vessel for a target application is not trivial and simple experiments are presented here for rice flour and bovine liver samples to illustrate effects of vessel design on digestion performance. Despite using the same heating program, the residual carbon contents varied from 22 to 67% to bovine liver digests and from 7 to 96% to rice flour digests. Quantitative recoveries were obtained for most analytes. Low recoveries were observed mainly for Ca and Fe. Analytical performance is related to different sizes, shapes and the gradient of temperature for each model of digestion vessel. It was demonstrated that taller vessels improved regeneration of nitric acid.

Mononuclear and binuclear RuII/arene/triphenylphosphine complexes with p-substituted benzoic acid derivatives were prepared and characterized. These monocationic complexes of type [Ru(η6-p-cymene)(PPh3)L] (L = benzoic acid (1), p-hydroxybenzoic acid (2), p-nitrobenzoic acid (3) and terephthalic acid (4)) were characterized using various techniques, such as nuclear magnetic resonance (NMR) and matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry, and the crystal structure of 1, 3 and 4 were determined by X-ray diffraction analysis. The cytotoxicity of the complexes was evaluated, in vitro, against tumorigenic [MDA-MB-231, MCF-7 (breast), A549 (lung) and DU-145 (prostate)] and non-tumorigenic [MCF-10A (breast), MRC-5 (lung) and PNT-2 (prostate)] cells. The binuclear complex (4) was inactive due to its low solubility. Complexes 1, 2 and 3 showed similar cytotoxicity, however, complex 1 presented better selectivity index against MDA-MB-231 than compounds 2 and 3. Cellular ruthenium absorption was explored by inductively coupled plasma mass spectrometry (ICP-MS) analyzing the whole cells and the culture medium. Complementary studies showed that complex 1 inhibited colony formation, induced morphology changes in cells and promoted cell cycle arrest in the Sub-G1 phase for the MDA-MB-231 cells.

This work aimed the development of an analytical procedure using inductively coupled plasma mass spectrometry (ICP-MS) in four modes of operation for simple and fast determination of Al, Ag, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, Li, Mg, Mn, Na, Ni, Pb, Sb, Se, Tl, Hg, V, U, and Zn in fresh and sea water samples attending simultaneously four Brazilian regulations, Ordinance No. 2914, ANVISA No. 274 and CONAMA Nos. 357 and 396. High matrix introduction system enables the introduction of sea water (3.5% m v-1 of NaCl) only 2-fold diluted. Collision cell mode was efficient to overcome polyatomic interferences. The procedure presented limits of detection (LODs) lower than maximum concentrations allowed by regulations. The CRM NIST 1643e and addition-recovery experiments were used to check accuracy and recoveries varied from 84 to 115%. ICP-MS combined with collision cell mode and aerosol dilution led to accurate and simultaneous determinations of 25 elements at different concentration levels in samples containing high contents of total dissolved solids.

In this study, two laser-based techniques, laser-induced breakdown spectroscopy (LIBS) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) were used for analytical signal evaluation of Ti, Al, and V and investigation of possible harmful elements eventually present as minor elements in Ti alloys. Due to the lack of certified reference materials, samples were also analyzed by wavelength dispersive X-ray fluorescence (WDXRF) and inductively coupled plasma optical emission spectrometry (ICP OES) after microwave-assisted digestion. To maximize the efficiency of LIBS and LA-ICP-MS, operational conditions were adjusted aiming to find optimal analytical performance. LIBS showed several Ti emission lines and few signals for Al and V. LA-ICP-MS was able to detect all three major constituents. For quantitative analysis, the correlation of intensity signals from LIBS analysis with reference values obtained by ICP OES was not successful, showing that there are still difficulties for quantification using solid samples. Measurements using ICP OES showed that additionally to major constituents, only Fe was present in concentrations around 0.2%. Analysis by WDXRF confirmed the presence of Fe. Results using both methods, i.e., ICP OES and WDXRF, were in good agreement.

Understanding instrumental analysis is essential for obtaining reliable analytical results required by chemists in a variety of research areas and industrial activities. All instrumental techniques involve undesirable background (BG) signals originated either from concomitants in the sample or by spurious (e.g. electrical or optical) effects intrinsically related to the measurement process. BG signals may affect accuracy, precision and detection limits. Techniques characterized by low BG stands out by high detectability even when they are based on processes with low efficiency (e.g. low quantum yields and low efficiency of thermal excitation). However, minor attention has been given to this topic in analytical chemistry courses hindering students' understanding of the BG concept and its impact on the analytical performance. Although in some analytical techniques BG is well-defined and successfully compensated, some of them still need further elucidation. Sources of BG and strategies for its minimization and correction are didactically discussed for a variety of analytical techniques, including molecular and atomic spectrometry, electroanalytical methods, and separation techniques. Historical aspects and recent approaches are also addressed.

In the present work, an inductively coupled plasma-tandem mass spectrometer (ICP-MS/MS) operating in single quadrupole and mass shift modes were evaluated for As determination in mineral fertilizers and agricultural gypsum with high contents of rare earth elements. For MS/MS mode, oxygen was the gas introduced into the octopole reaction system (ORS3). Samples were prepared by microwave-assisted digestion with diluted nitric acid solution. The accuracy was checked by analysis of a fertilizer certified reference material (NIST SRM 695) and by addition and recovery experiments. When operating in single quadrupole mode, recoveries ranged from 59 to 151%; while values obtained by MS/MS mode varied from 81 to 105% when 0.30 mL min-1 O2 was introduced into the ORS3. Limits of detection for As+ in single quadrupole and AsO+ in MS/MS mass shift mode were 6 and 9 ng L-1, respectively.