The use of a gold disc microelectrode for the determination of copper in human sweat

A novel approach of using a gold disc microelectrode to analyze sweat samples for copper ions by anodic square wave stripping voltammetry (SW stripping voltammetry) is described Sweat was collected from the lower back of four subjects after physical exercise and the sample volume required for the determinations was 100 mu L. Under the optimized conditions the calibration plot was linear over the range 1-100 mu mol L(-1) Cu(II) with a limit of detection of 0 25 mu mol L(-1) The precision was evaluated by carrying out five replicate measurements in a 1 mu mol L(-1) Cu(II) solution and the standard deviation was found to be 1 5% Measurements were performed by inserting the microelectrode into sweat drops and Cu(II) concentrations in the analyzed samples ranged from 09 to 28 mu mol L(-1) Values obtained by the proposed voltammetric method agreed well with those found using graphite furnace atomic absorption spectroscopy (GFAAS) (C) 2010 Elsevier B V All rights reserved

Versatile microanalytical system with porous polypropylene capillary membrane for calibration gas generation and trace gaseous pollutants sampling applied to the analysis of formaldehyde, formic acid, acetic acid and ammonia in outdoor air

The analytical determination of atmospheric pollutants still presents challenges due to the low-level concentrations (frequently in the mu g m(-3) range) and their variations with sampling site and time In this work a capillary membrane diffusion scrubber (CMDS) was scaled down to match with capillary electrophoresis (CE) a quick separation technique that requires nothing more than some nanoliters of sample and when combined with capacitively coupled contactless conductometric detection (C(4)D) is particularly favorable for ionic species that do not absorb in the UV-vis region like the target analytes formaldehyde formic acid acetic acid and ammonium The CMDS was coaxially assembled inside a PTFE tube and fed with acceptor phase (deionized water for species with a high Henry s constant such as formaldehyde and carboxylic acids or acidic solution for ammonia sampling with equilibrium displacement to the non-volatile ammonium ion) at a low flow rate (8 3 nLs(-1)) while the sample was aspirated through the annular gap of the concentric tubes at 25 mLs(-1) A second unit in all similar to the CMDS was operated as a capillary membrane diffusion emitter (CMDE) generating a gas flow with know concentrations of ammonia for the evaluation of the CMDS The fluids of the system were driven with inexpensive aquarium air pumps and the collected samples were stored in vials cooled by a Peltier element Complete protocols were developed for the analysis in air of NH(3) CH(3)COOH HCOOH and with a derivatization setup CH(2)O by associating the CMDS collection with the determination by CE-C(4)D The ammonia concentrations obtained by electrophoresis were checked against the reference spectrophotometric method based on Berthelot s reaction Sensitivity enhancements of this reference method were achieved by using a modified Berthelot reaction solenoid micro-pumps for liquid propulsion and a long optical path cell based on a liquid core waveguide (LCW) All techniques and methods of this work are in line with the green analytical chemistry trends (C) 2010 Elsevier B V All rights reserved

Fully electrochemical hyphenated flow system for preconcentration, cleanup, stripping, capillary electrophoresis with stacking and contactless conductivity detection of trace heavy metals

Successful coupling of electrochemical preconcentration (EPC) to capillary electrophoresis (CE) with contactless conductivity detection (C(4)D) is reported for the first time. The EPC-CE interface comprises a dual glassy carbon electrode (GCE) block, a spacer and an upper block with flow inlet and outlet, pseudo-reference electrode and a fitting for the CE silica column, consisting of an orifice perpendicular to the surface of a glassy carbon electrode with a bushing inside to ensure a tight press fit. The end of the capillary in contact with the GCE is slant polished, thus defining a reproducible distance from the electrode surface to the column bore. First results with EPC-CE-C(4)D are very promising, as revealed by enrichment factors of two orders of magnitude for Tl, Cu, Pb and Cd ion peak area signals. Detection limits for 10 min deposition time fall around 20 nmol L(-1) with linear calibration curves over a wide range. Besides preconcentration, easy matrix exchange between accumulation and stripping/injection favors procedures like sample cleanup and optimization of pH, ionic strength and complexing power. This was demonstrated for highly saline samples by using a low conductivity buffer for stripping/injection to improve separation and promote field-enhanced sample stacking during electromigration along the capillary. (C) 2010 Elsevier B.V. All rights reserved.

Magnetic coupled electrochemistry: Exploring the use of superparamagnetic nanoparticles for capturing, transporting and concentrating trace amounts of analytes

We propose the use of functionalized superparamagnetic nanoparticles for capturing, and transporting analytes, in association with an external miniature magnet to deposit such nanocarrier species at the electrode surface. This approach can be employed for the electroanalytical determination of chemical species capable of interacting with the nanoparticles, or in the opposite case, to block their response at the electrode surface. The concept was successfully demonstrated by using aminofunctionalized nanoparticles to block the discharge of hexacyanoferrate(II) ions, and to enhance the signals of aquapentacyanoferrate(II) ions via coordination to the surface amino groups. Selective analysis was also performed for silver ions, surpassing the stripping methods in terms of versatility and usefulness. (C) 2010 Elsevier B.V. All rights reserved.

Trace-metal biogeochemistry in the Mediterranean Thau Lagoon, a shellfish farming area

The present study contributes to the knowledge of the biogeochemistry of Pb, Cd, Cu, and Ni in the Mediterranean Than Lagoon, southern France, which is an important shellfish farming system. The concentrations of the metals were determined in sediment cores and the overlying waters using inductively coupled plasma mass spectrometry. Particular attention was given to the determination of dissolved Cu species because of their dual role as essential nutrient and toxicant to planktonic organisms. Dissolved Cu speciation was determined using the diffusive gradient in thin-film technique (DGT) and competitive ligand exchange-adsorptive cathodic stripping voltammetry (CLE-ACSV). Our data indicated a significant historical contamination of the sediments, which commenced in the second half of the 19th century, with trace metal inputs persisting until the end of the 20th century. In recent years a decrease in metal contamination has become apparent. The maxima observed for Pb, Cd, and Cu profiles probably indicate the occurence of anoxia crises. A strong complexation of the dissolved Cu species was observed in the waters of the Than Lagoon, which reduced the bioavailability of Cu. The dissolved Cu(2+) concentrations were probably too low to cause direct toxic effects on shellfish, but the highest concentration (5.29 pM) observed in this study can potentially influence phytoplankton communities. A comparison between the Cu speciation data indicates that up to 50% of the complexed Cu determined using CLE-ACSV was DGT labile.

Automated two-dimensional separation flow system with electrochemical preconcentration, stripping, capillary electrophoresis and contactless conductivity detection for trace metal ion analysis

This paper describes the automation of a fully electrochemical system for preconcentration, cleanup, separation and detection, comprising the hyphenation of a thin layer electrochemical flow cell with CE coupled with contactless conductivity detection (CE-C(4)D). Traces of heavy metal ions were extracted from the pulsed-flowing sample and accumulated on a glassy carbon working electrode by electroreduction for some minutes. Anodic stripping of the accumulated metals was synchronized with hydrodynamic injection into the capillary. The effect of the angle of the slant polished tip of the CE capillary and its orientation against the working electrode in the electrochemical preconcentration (EPC) flow cell and of the accumulation time were studied, aiming at maximum CE-C(4)D signal enhancement. After 6 min of EPC, enhancement factors close to 50 times were obtained for thallium, lead, cadmium and copper ions, and about 16 for zinc ions. Limits of detection below 25 nmol/L were estimated for all target analytes but zinc. A second separation dimension was added to the CE separation capabilities by staircase scanning of the potentiostatic deposition and/or stripping potentials of metal ions, as implemented with the EPC-CE-C(4)D flow system. A matrix exchange between the deposition and stripping steps, highly valuable for sample cleanup, can be straightforwardly programmed with the multi-pumping flow management system. The automated simultaneous determination of the traces of five accumulable heavy metals together with four non-accumulated alkaline and alkaline earth metals in a single run was demonstrated, to highlight the potentiality of the system.

Trace element impurity determination in aspirin tablets by INAA

Instrumental neutron activation analysis (INAA) was applied to assess trace element concentrations in six samples of aspirin tablets acquired in SA o pound Paulo city, Brazil. Concentrations of the elements Br, Ca, Co, Cr, Fe, K, La, Na, Sc and Zn were determined. Comparisons were made between the results obtained with published data for aspirins from foreign countries. Certified reference materials, INCT-MPH-2 Mixed Polish Herbs were analyzed for quality control of the analytical results.

From Pettson and Findus to Festus and Mercury...and Back Again: A Comparison of Four Translations of Sven Nordqvist's Picture Books

In order to examine how children's literature might be translated, two different English translations of two Swedish picture books have been analyzed. The original Swedish books are Rävjakten and Pannkakstårtan by Sven Nordqvist. Rävjakten was translated as The Fox Hunt in 1988 and as The Fox Hunt in 2000. Pannkakstårtan was translated as Pancake Pie in 1985 and as The Birthday Cake in 1999. Literary translation in general, specific translation issues for children's literature, and trends in international English style have been considered. Analysis of the four texts has been made, with consideration given to the following areas: changes in illustrations, layout, or format; text changes; lexical choices; and retention, deletion, or modification of names and culturally specific references. The analysis revealed that the following tendencies were true for the later translations: foreignization of the text, word-for-word translation of the text, and a neutral international English variety.

Utveckling och analys av en PIC-mikrokontrollers möjligheter att kommunicera via TCP/IP

Sterners Specialfabrik AB tillverkar bland annat mynt- och biljettautomater. För att underlätta felsökning, underhåll, avläsning av statistik med mera på en automat är det lämpligt att detta utförs på en PC över Internet. Det innebär att automaten inte behöver besökas då dessa uppgifter skall utföras. Examensarbetet går ut på att få en PIC mikrokontroller att kommunicera med en användare vid en PC över internet. För detta krävs att en TCP/IP stack implementeras på PICmikrokontrollern. Arbetet ledde till en fungerande demoapplikation som klarar av att kommunicera över TCP/IP. Demoapplikationen innehåller diverse olika funktioner för att demonstrera hur en automat skulle kunna styras och övervakas.

Underkuvade kunskaper och genealogins möjligheter

Subjugated knowledges and the possibilities of genealogy The article explores the possibilities of “voicing” marginalized subjects by analyzing letters written by female mental patients in the beginning of the twentieth century. Following Michel Foucault, genealogy is here used as a means to explore and reclaim subjugated knowledges, i.e. knowledges that have been dismissed, distorted, disqualified and put aside by more powerful and ultimately victorious knowledge claims, in this case the psychiatric discourse. Historically oriented research on madness has often explored medical and cultural discourses and representations, as these correspond to sources that can be easily found in archives. This also means that mental patients’ own narratives and texts have been more difficult to trace, partly due to the paucity of available documentation. Herein lies a challenge: how can we represent these subjects, whose stories are inevitably always already captured and filtered by authorities, without portraying them either as passive victims or reducing them to effects of power networks? The article thus ponders research ethics, the question of Otherness and the power of representations. The difficulties in representing female patients’ “own”voices are discussed, yet the article points to the necessity of taking voices that are simultaneously in the margins and in the centre of more powerful discourses, seriously as objects of knowledge. The article argues that “the insurrection of subjugated knowledges”, i.e. bringing back such knowledges as represented here by mental patients’ narratives, opens us otherpossibilities of knowledge. Hence, mental patients’ letters are seen as important “fractures” in the official and legitimized knowledge of madness, offering alternative understandings of both committed individuals and the psychiatric discourse itself.

Pregnancy-related low back pain and pelvic girdle pain approximately 14 months after pregnancy : pain status, self-rated health and family situation

Background: Pelvic girdle pain (PGP) in pregnancy is distinct from pregnancy-related low back pain (PLBP). However, women with combined PLBP and PGP report more serious consequences in terms of health and function. PGP has been estimated to affect about half of pregnant women, where 25% experience serious pain and 8% experience severe disability. To date there are relatively few studies regarding persistent PLBP/PGP postpartum of more than 3 months, thus the main objective was to identify the prevalence of persistent PLBP and PGP as well as the differences over time in regard to pain status, self-rated health (SRH) and family situation at 12 months postpartum. Methods: The study is a 12 month follow-up of a cohort of pregnant women developing PLBP and PGP during pregnancy, and who experienced persistent pain at 6 month follow-up after pregnancy. Women reporting PLBP/PGP (n = 639) during pregnancy were followed up with a second questionnaire at approximately six month after delivery. Women reporting recurrent or persistent LBP/PGP at the second questionnaire (n = 200) were sent a third questionnaire at 12 month postpartum. Results: A total of 176 women responded to the questionnaire. Thirty-four women (19.3%) reported remission of LBP/PGP, whereas 65.3% (n = 115) and 15.3% (n = 27), reported recurrent LBP/PGP or continuous LBP/PGP, respectively. The time between base line and the 12 months follow-up was in actuality 14 months. Women with previous LBP before pregnancy had an increased odds ratio (OR) of reporting 'recurrent pain' (OR = 2.47) or 'continuous pain' (OR = 3.35) postpartum compared to women who reported 'no pain' at the follow-up. Women with 'continuous pain' reported statistically significant higher level of pain at all measure points (0, 6 and 12 months postpartum). Non-responders were found to report a statistically significant less positive scoring regarding relationship satisfaction compared to responders. Conclusions: The results from this study demonstrate that persistent PLBP/PGP is a major individual and public health issue among women 14 months postpartum, negatively affecting their self-reported health. However, the perceived relationship satisfaction seems to be stable between the groups.