Trace Ions Research Articles

Evaluating water quality of rock glacier outflows in the Western Alps, Italy: a regional perspective.

Intact rock glaciers (RG) are considered valuable water storage because containing permafrost ice volumes. The hydrological relevance of RG is forecasted to increase with respect to glaciers under climate change scenarios, as well as RG's role as water resources in alpine basins for multiple uses. Besides the assessment of water amount stored in intact rock glaciers, the evaluation of water quality is of primary importance. Here, we present the results of a chemical survey performed on five outflows from intact RG in 2020-2023 in the Piedmont region, Western Alps, Italy, along a latitudinal gradient and in different geological settings. The survey aimed to assess the water quality of RG outflows based on chemical indicators (major ions, nutrients, trace metals). Sampling and analyses were performed according to standard methods for freshwater samples, paying specific attention to the analytical quality and consistency of the data. We considered seasonal and interannual variability of the main chemical variables and the possible effects of RG outflows on the chemistry of lakes and ponds located in proximity to the RG. All the investigated sites were characterized by low to moderate ion content, low nutrients, and trace metals close to or below the detection limit, indicating a good water quality status. Results suggested lithology as the main factor affecting the chemical composition of RG outflows. The results of this study indicate it is advisable to develop shared protocols and joint monitoring programs for data collecting at RG outflow sites all over the Alps, possibly integrating chemical and biological indicators, with the final aim of monitoring the water quality of these valuable resources and its temporal evolution under climate change.

Ion Coupling, Bonding, and Transfer in Narrow Carbon Nanotubes.

Narrow carbon nanotubes (nCNT) are unique mimics of biological channels with water-ion selectivity attractive for applications such as water purification and osmotic energy harvesting, yet their understanding is still incomplete. Here, an ab initio computation is employed to develop the full picture of ion transfer in nCNT including specificity and coupling between ions. The thermodynamic costs of ion transfer are computed for single ions and ion pairs and used to evaluate different local coupling scenarios including strong (pairing) and weak (free-ion) coupling as well as "electroneutrality breakdown" (EB), possible for cations only due to their chemisorption-like interaction with nCNT. The results also indicate that nCNT behaves as a highly polarizable metal-like shell, which eliminates the dielectric energy when CNT accommodates coupled cation and anion. This allows facile computation and comparison of the full transfer costs, including translation entropy, for different ions in different coupling modes to identify the dominant regime. EB transfer appears most favorable for K+, while anions strongly favor transfer as pairs, except for chloride which favors weak coupling and, at neutral pH, transfers as a trace ion coupled to both cation and OH-. The results demonstrate that, in general, observed ion permeation and conduction in nCNT, especially for anions, reflect a complex ion-specific and composition-dependent interplay between different ions.

Pushing the Limits of Capacitively Coupled Contactless Conductivity Detection for Capillary Electrophoresis.

Capillary electrophoresis with capacitively coupled contactless conductivity detection (CE-C4D) has proven to be an efficient technique for the separation and detection of charged inorganic, organic, and biochemical analytes. It offers several advantages, including cost-effectiveness, nanoliter injection volume, short analysis time, good separation efficiency, suitability for miniaturization, and portability. However, the routine determination of common inorganic cations (NH4+, K+, Na+, Ca2+, Mg2+, and Li+) and inorganic anions (F-, Cl-, Br-, NO2-, NO3-, PO43-, and SO42-) in water quality monitoring typically exhibits limits of detection of about 0.3-1 μM without preconcentration. This sensitivity often proves insufficient for the applications of CE-C4D in trace analysis situations. Here, we explore methods to push the detection limits of CE-C4D through a comprehensive consideration of signal and noise sources. In particular, we (i) studied the model of C4D and its guiding roles in C4D and CE-C4D, (ii) optimized the bandwidth and noise performance of the current-to-voltage (I-V) converter, and (iii) reduced the noise level due to the strong background signal of the background electrolyte by adaptive differential detection. We characterized the system with Li+; the 3-fold signal-to-noise (S/N) detection limit for Li+ was determined at 20 nM, with a linear range spanning from 60 nM to 1.6 mM. Moreover, the optimized CE-C4D method was applied to the analysis of common mixed inorganic cations (K+, Na+, Ca2+, Mg2+, and Li+), anions (F-, Cl-, Br-, NO2-, NO3-, PO43-, and SO42-), toxic halides (BrO3-) and heavy metal ions (Pb2+, Cd2+, Cr3+, Co2+, Ni2+, Zn2+, and Cu2+) at trace concentrations of 200 nM. All electropherograms showed good S/N ratios, thus proving its applicability and accuracy. Our results have shown that the developed CE-C4D method is feasible for trace ion analysis in water quality control.

Hydrogel binding sodium alginate based optical fiber surface plasmon resonance for calcium ion trace detection

A plasmonic tilted fiber Bragg grating (TFBG)-based sensor for the detection of calcium ion (Ca2+) was proposed and demonstrated experimentally. Hydrogel material was synthesized by utilizing hydrogen bond recombination between cellulose nanocrystals (CNC) and polyvinyl alcohol (PVA). Sodium alginate (SA) was incorporated into this hydrogel material, resulting in a composite membrane with specific binding properties for Ca2+. The membrane was applied as a coating on the surface of a gold-coated TFBG. The CNC/PVA-SA modified gold on the TFBG surface enhanced the localized refractive index changes caused by variations of Ca2+ concentrations. The experimental results demonstrated an impressive limit of detection (LOD) of approximately 0.025 fM, which is five orders of magnitude better than the current LODs of similar Ca2+ sensors. And the proposed Ca2+ sensor exhibited a wide dynamic range of 10−16 M to 10−6 M.

Evaluating health risks from the release of trace elements to groundwater by rock-water interaction in a weathered gneissic aquifer.

High concentration of trace elements in groundwater poses more health risks to humans by drinking groundwater and dermal contact. This work aimed to assess the trace element concentrationin groundwater, water quality for drinking purposes, and its effect on human health upon prolonged consumption. The study was carried out in the gneissic terrain of Perambalur District, Tamil Nadu, India, where groundwater is used mainly for drinking, agricultural, and domestic purposes. Hydrochemistry, water quality, and health risk assessments of trace elements from 44 groundwater samples for pre- and post-monsoon were determined by drinking water quality, hazard quotient, hazard index, and carcinogenic risk. The dominance of trace elements in groundwater was in the order of Zn > Fe > Cu > Ni > Te > Pb > Co. Ni and Co are released more during the post-monsoon, and Zn, Fe, Cu, and Pb concentration during the pre-monsoon. The dominant type of groundwater was Ca-HCO3 and mixed Ca-Mg-Cl type. The dissolution of fissile hornblende biotite gneissic rock dissolves more trace elements to groundwater than charnockite rock. The correlation matrix indicates that major ion and trace elements were positively good in groundwater during the pre-monsoon and post-monsoon 2018. The principal component analysis suggests that the weathering of rocks, rainwater recharge, and evaporation processes controlled the hydrochemistry of trace and major ions. The concentration of Pb, Ni, and Cd elements exceeded the permissible limit of BIS and WHO; these elements are unsuitable for drinking. The trace element concentration in groundwater was good for drinking and irrigation in the study area, except in a few wells. The hazard quotient and hazard index were computed, which revealed that non-carcinogenic risk to human health by drinking groundwater was more of a problem for children than adults. This study will help prevent children from health risks of trace elements.

The Development of Aspergillus flavus and Biosynthesis of Aflatoxin B1 are Regulated by the Golgi-Localized Mn2+ Transporter Pmr1.

Microorganisms rely on diverse ion transport and trace elements to sustain growth, development, and secondary metabolism. Manganese (Mn2+) is essential for various biological processes and plays a crucial role in the metabolism of human cells, plants, and yeast. In Aspergillus flavus, we confirmed that Pmr1 localized in cis- and medial-Golgi compartments was critical in facilitating Mn2+ transport, fungal growth, development, secondary metabolism, and glycosylation. In comparison to the wild type, the Δpmr1 mutant displayed heightened sensitivity to environmental stress, accompanied by inhibited synthesis of aflatoxin B1, kojic acid, and a substantial reduction in pathogenicity toward peanuts and maize. Interestingly, the addition of exogenous Mn2+ effectively rectified the developmental and secondary metabolic defects in the Δpmr1 mutant. However, Mn2+ supplement failed to restore the growth and development of the Δpmr1Δgdt1 double mutant, which indicated that the Gdt1 compensated for the functional deficiency of pmr1. In addition, our results showed that pmr1 knockout leads to an upregulation of O-glycosyl-N-acetylglucose (O-GlcNAc) and O-GlcNAc transferase (OGT), while Mn2+ supplementation can restore the glycosylation in A. flavus. Collectively, this study indicates that the pmr1 regulates Mn2+ via Golgi and maintains growth and metabolism functions of A. flavus through regulation of the glycosylation.

Excited-state intramolecular proton transfer (ESIPT) active interwoven polycatenated coordination polymer for selective detection of Al3+ and Ag+ ions along with water detection in less polar solvents.

The external stimuli-responsive excited-state intramolecular proton transfer (ESIPT) on/off mechanism is a unique and expedient sensing method that offers easy monitoring through the transition between dual and single-peak emissions. To avail this advantage of ESIPT-based sensing for selective metal ion detection and trace water detection, we have synthesized a 2,5-dihydroxyterephthalate (dht)-based interwoven polycatenated coordination polymer (1). The synthesized compound has been thoroughly characterized using single-crystal and powder X-ray diffraction techniques, along with other physicochemical methods. The synthesized compound exhibits a visual luminescence color change from faint yellow to bright green under UV irradiation in the presence of Al3+ ions. This change is attributed to a blue shift in fluorescence maxima of the keto form of the dht ligand in contact with Al3+ ions. Additionally, the material detects Ag+ ions through an ESIPT-off mechanism. These significant changes in ESIPT - blue shifting for Al3+ and ESIPT-off for Ag+ - start in just 1 mM aqueous solutions of these ions. Significantly, the ESIPT-off for Ag+ is evident even in the presence of other interfering ions. Beyond metal ion detection, this material also offers both qualitative and quantitative sensing of trace amounts of water in various polar organic solvents, such as ethanol (EtOH), tetrahydrofuran (THF), isopropanol (IPA), acetone, and acetonitrile (ACN), through the ESIPT-on/off phenomenon. The activated framework of compound 1 (1') can detect 2%, 4%, 4%, 3%, and 3% water in acetone, ACN, EtOH, IPA, and THF, respectively; through the conversion from a single to dual hump emission alteration. The respective ESIPT peak shift and ESIPT-on/off in the presence of metal ions and water is explained by the interaction between the host coordination polymer and guest analytes.

Three-dimensional concentration-polarization modeling of trace-ions in reverse osmosis

Concentration polarization (CP) is mostly evaluated through one-dimensional (1D) film models considering convective and diffusive transport of solutes. However, in multicomponent ionic solutions, electromigration and chemical speciation may also play a role in the solute transport within the CP layer, thus affecting the process performance. We developed a three-dimensional (3D) numerical model for evaluating the CP in spacer-filled feed reverse osmosis (RO) channels by coupling hydrodynamics with the transport of solutes by convection, diffusion and electromigration, and chemical speciation by several ion-pairing equilibria. A realistic spacer geometry was obtained by CT-scans of commercial RO spacers. The model revealed highly non-uniform distributions of CP, mass transfer coefficients and precipitation potential on the membrane. While electromigration tends to equalize the fluxes of dominant ions, increases locally the CP of anions and decreases that of cations, it was found not to significantly affect the boundary layer thickness. However, the chemical speciation strongly affected the CP of trace ions binding with dominant ions. Finally, the 3D results were compared with those obtained from simpler 1D models. While 1D approaches help explaining qualitatively the effects of electromigration and speciation, and serve as a reasonable first approximation, they do not capture the non-uniform distribution of concentrations, mass transfer rates or saturation indices. The model will be used to study the full length of an RO membrane module and thus provide better indicators of the overall performance of the separation process.

An automatic and smart platform for rapid detection of cadmium and lead simultaneously in rice using triple-amplified chemiluminescence immunoassay

Rapid detection of trace ions is urgently needed for large-scale screening to ensure food safety. This study developed an innovative and automatic strategy, based on a smart-designed platform for rapid detection of cadmium and lead in rice. As bridge antibody, the antigen was conjugated with goat anti-mouse immunoglobulin G labeled alkaline phosphatase. Meanwhile, a biotin-streptavidin system was introduced to micromagnetic particles, thus providing a triple-amplified chemiluminescence immunoassay with high sensitivity, accuracy and specificity. The limits of detection for cadmium and lead were 0.06 and 1.00 ng mL−1, respectively, within 30 min. The recoveries ranged from 89.81 to 114.92 %, with relative standard deviations less than 9.2 %. The results obtained agreed with those of inductively coupled plasma–mass spectrometry and certified reference materials. Additionally, the auto-operation avoided human errors as well as being convenient, fast, automatic and high-throughput. Therefore, this smart platform can be applied for large-scale Cd2+ and Pb2+ screening.

Oxyanion Removal from Impaired Water by Donnan Dialysis Plug Flow Contactors.

In the last twenty-five years, extensive work has been done on ion exchange membrane bioreactors (IEMB) combining Donnan dialysis and anaerobic reduction to remove trace oxyanions (e.g., perchlorate, nitrate, chlorate, arsenate) from contaminated water sources. Most studies used Donnan dialysis contactors with high recirculation rates on the feed side, so under continuous operation, the effective concentration on the feed side of the membrane is the same as the exit concentration (CSTR mode). We have built, characterized, and modelled a plug flow Donnan dialysis contactor (PFR) that maximizes concentration on the feed side and operated it on feed solutions spiked with perchlorate and nitrate ion using ACS and PCA-100 anion exchange membranes. At identical feed inlet concentrations with the ACS membrane, membrane area loading rates are three-fold greater, and fluxes are more than double in the PFR contactor than in the CSTR contactor. A model based on the nonlinear adsorption of perchlorate in ACS membrane correctly predicted the trace ion concentration as a function of space-time in experiments with ACS. For PCA membrane, a linear flux dependence on feed concentration correctly described trace ion feed concentration as a function of space-time. Anion permeability for PCA-100 was high enough that the overall mass transfer was affected by the film boundary layer resistance. These results provide a basis for efficiently scaling up Donnan dialysis contactors and incorporating them in full-scale IEMB setups.

Role of EDTA, citrate and phthalate on Cs, Sr, Eu and U adsorption by smectite and evaluation by geochemical modeling

The presence of organic ligands may exacerbate the mobility of contaminants by stabilizing them in the aqueous phase and reducing their retention on the solid phases, representing an additional environmental hazard.We investigated the impact of EDTA, citrate and phthalate on the adsorption of four different radionuclides (RN = 137Cs, 85Sr, 152Eu and 233U) by a well-characterized smectite clay and evaluated the capability of sorption modeling to incorporate the impact of these organic ligands.We analyzed the effect of ligand concentration (from 1·10−6 to 1·10−3 M) on RN retention at two different pH values (approximately 5 and 9) to contemplate the occurrence of different adsorption mechanisms in clays (cation exchange or surface complexation) as well as the RN and organic speciation.The results suggested that phthalate had a minimal effect on the retention of the studied RNs, while EDTA and citrate significantly decreased the adsorption of Eu, Sr and U, even making it drop to zero in some cases. The simulation outcomes demonstrated that, in most cases, the variation in the distribution coefficient (Kd) as a function of the organic concentration could be accurately replicated with the available thermodynamic data, but few relevant discrepancies were identified.The importance of the possible competitive effects of trace ions in the equilibrium water (notably Ca) for the overall assessment of the role of organic matter on RN retention was highlighted.

Use of major ion chemistry and trace and rare earth elements to characterize hydraulic relations, mixing processes and water–rock interaction in the Dong Van karst aquifer system, Northern Vietnam

The effectiveness of using a groundwater geochemistry approach in karst hydrogeologic research is highlighted. In particular, this approach is useful for preliminary investigations, such as for the study described here on the Dong Van karst aquifer system in Northern Vietnam. Analyses of different groundwater chemistry parameters complement each other, to clarify hydrochemical processes that are occurring in the karst system. The results of this study show that major ion composition can be used to clarify water chemistry signatures, as well as to identify the mixing processes and water–rock interactions in aquifers. Meanwhile, trace element concentrations and rare earth element patterns can be used as potential natural tracers when some processes are not revealed through conventional hydrochemical methods. These natural tracers can also be used to identify contaminant sources and/or contaminant transport pathways in karst aquifers. Viewed holistically, the groundwater geochemistry approach provides scientific information to establish a basic hydrogeological conceptual model and to estimate the water balance, which has implications for water resources protection and management in karstic systems.

Elucidation of composition of chlorine compounds in acidic sodium chlorite solution using ion chromatography.

With the spread of coronavirus infections, the demand for disinfectants, such as a sodium chlorite solution, has increased worldwide. Sodium chlorite solution is a food additive and is used in a wide range of applications. There is evidence that chlorous acid or sodium chlorite is effective against various bacteria, but the actual mechanism is not well understood. One reason for this is that the composition of chlorine-based compounds contained in sodium chlorite solutions has not been clearly elucidated. The composition can vary greatly with pH. In addition, the conventional iodometric titration method, the N,N-diethyl-p-phenylenediamine sulfate (DPD) method and the absorption photometric method cannot clarify the composition. In this study, we attempted to elucidate the composition of a sodium chlorite solution using absorption spectrophotometry and ion chromatography (IC). IC is excellent for qualitative and quantitative analysis of trace ions. Through this, we aimed to develop an evaluation method that allows anyone to easily determine the bactericidal power of sodium chlorite. We found that commercially available sodium chlorite solution is 80% pure, with the remaining 20% potentially containing sodium hypochlorite solution. In addition, when sodium chlorite solution became acidified, its absorption spectrum exhibited a peak at 365 nm. Sodium chlorite solution is normally alkaline, and it cannot be measured by the DPD method, which is only applicable under acidic conditions. The presence of a peak at 365 nm indicates that the acidic sodium chlorite solution contains species with oxidizing power. On the other hand, the IC analysis showed a gradual decrease in chlorite ions in the acidic sodium chlorite solution. These results indicate that chlorite ions may not react with this DPD reagent, and other oxidizing species may be present in the acidic sodium chlorite solution. In summary, when a sodium chlorite solution becomes acidic, chlorine-based oxidizing species produce an absorption peak at 365 nm. Sodium hypochlorite and sodium chlorite solutions have completely different IC peak profiles. Although there are still many problems to be solved, we believe that the use of IC will facilitate the elucidation of the composition of sodium chlorite solution and its sterilization mechanism.

Sensitive quantification of mercury ions in real water systems based on an aggregation-collision electrochemical detection

Nanoparticle impact electrochemistry (NIE) is an emerging electroanalytical technique that has been utilized to the sensitive detection of a wide range of biological species. So far, the NIE based trace ion detection is largely unexplored due to the lack of effective signal amplification strategies. We herein develop an NIE-based electrochemical sensing platform that utilizes T-Hg2+-T coordination induced AgNP aggregation to detect Hg2+ in aqueous solution. The proposed aggregation-collision strategy enables highly sensitive and selective detection. A dual-mode analysis based on the change in impact frequency and oxidative charge of the anodic oxidation of the AgNPs in NIE allows for more accurate self-validated quantification. Furthermore, the current NIE-based sensor demonstrates reliable analysis of Hg2+ of real water samples, showing great potential for practical environmental monitoring and point-of-care testing (POCT) applications.

Tilted fiber Bragg grating surface plasmon resonance based optical fiber cadmium ion trace detection

A plasmonic tilted fiber Bragg grating (TFBG)-based sensor for the detection of cadmium ion (Cd2+) is proposed and demonstrated experimentally. The TFBG is coated with a thin gold film, where glutathione (GSH) can self-assemble on the gold coating to bond Cd2+ and form complexes. To enhance Cd2+ sensitivity, GSH-modified gold nanoparticles are used to amplify localized refractive index changes around TFBG surface, induced by Cd2+ concentration variations. The experimental results indicate a limit of detection of ∼0.06 nM, which is two orders better than reported fiber grating-based Cd2+ sensors. Additionally, the proposed TFBG sensor performs a wide dynamic range from 0.01 nM to 1000 nM for Cd2+ detections and temperature-compensated wavelength monitoring with Bragg resonance.

Simple software solution for N2 diversion when measuring δ18O values of nitrogen-rich samples materials using a Thermo Scientific EA-IRMS System

This method is a simple, cost-free, and reliable approach for the removal of N2 interference on a CO analyte when analysing nitrogen-rich (>0.5% w/w) samples by Elemental Analysis Isotope Ratio Mass Spectrometry. Specifically, the isobaric interference on m/z 30 is eliminated using only the open split of the Thermo Scientific ConFlo IV Universal Interface Device, improving the analytical workflow when using a static temperature Gas Chromatography (GC) column. It simplifies the N2 diversion methods described in recent decades. When applied, the method described here:•Provides sufficient baseline resolution between the N2 and CO analytes, to permit quantitative N2 diversion, using an extended length packed GC column;•Quantitatively eliminates all N2 analyte from the analytical gas stream ensuring that no N2 enters the ion source and therefore no isobaric interference is produced on m/z 30 ion trace of the CO analyte;•Allows reproducible measurement of δ18O values from nitrogen-rich sample materials without a N2 isobaric interference, where the CO analyte is measured on the analytical baseline that it was produced on in the reactor (i.e., no addition make-up helium or new baseline of pure helium for the CO analyte).

Modular dual mobility articulation in primary and revision hip arthroplasty: lights and shadows

PurposeThe use of dual mobility cups in total hip arthroplasty has gained popularity in light of the fact it enables to reduce dislocation through increased jumping distance (JD) and impingement-free arc of movement. Modular Dual Mobility Cup (modular DMC) systems have been recently introduced to enable the use of dual mobility cups with standard metal-backed shells. The objective of this study was twofold: calculate the JD for each modular DMC system and conduct a systematic literature review to report clinical outcomes and reasons for failure of this construct.MethodsThe JD was calculated using the Sariali formula: JD = 2Rsin [(π/2 − Ψ − arcsin (offset/R))/2]. A qualitative systematic literature review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A comprehensive search for English and French articles between January 2000 and July 2020 was run on PubMed, EMBASE, Google Scholar, and Scopus with the primary objective of finding articles about modular DMC systems.ResultsWe identified eight 8 different manufacturers of modular DMC systems and 327 publications on the subject. After screening for duplicates and eligibility, we identified 229 publications: 206 articles were excluded because they contained no reports on modular DMC systems, whereas other three were not included because they focused on biomechanical aspects. Among the 11 included articles, 2 were prospective case series, 9 were retrospective case series. True dislocation occurred in 25 cases (0.9%), and six of them were solved by closed reduction without necessity of revision, while all 5 intraprosthetic dislocations were operated.ConclusionsModular DMCs are a valid method to deal with complex THA instability, with good clinical and patient-reported outcomes, low complication rates, and low revision rates at early follow-up. We would advise cautious optimism on the role of modular DMC implants, as it seems safer to use ceramic instead of metallic heads whenever possible to avoid the increase cobalt and chromium trace ion serum levels.

Physico-Chemical and Trace Metal Analysis in Groundwater of Nagapattinam Region in Nagapattinam District of Tamilnadu State

The aim of the present work is to find the quality of water in and around the Nagapattinam region and geochemical study of water and its chemical composition with qualitative and quantitatively assessed from the period of post monsoon ( January) in the year 2020. Therefore, ten underground water sample were taken from different areas in Nagapattinam region and analysed for the following qualities such as Color, odour, temperature, Electrical conductivity, total dissolved solid, Hydrogen ion Concentration, calcium, magnesium, chloride, potassium, sodium, nitrate, and sulphate and trace metals like manganese, lead, chromium, copper, iron, arsenic, cadmium and zinc. The physico chemical parameters indicate the quality of ground water varies from bore well to bore well. Higher values of any parameter in a borehole indicate that the water is not fit for drinking. Therefore, the public is advised that the groundwater source in the study area should be monitored before it is used for domestic and drinking water purposes and that the government should adopt some treatment technology in the current study regions to minimize the hardness and salinity for provide safe water to the public.

Biomimetic ion substituted and Co-substituted hydroxyapatite nanoparticle synthesis using Serratia Marcescens

Biomimicry is becoming deep-rooted as part of bioceramics owing to its numerous functional advantages. Naturally occurring hydroxyapatite (HA) apart from primary nano structures are also characterised by various ionic substitutions. The ease of accommodating such key elements into the HA lattice is known to enhance bone healing properties of bioceramics. In this work, hydroxyapatite synthesized via biomimetic approach was substituted with individual as well as multiple cations for potential applications in bone repair. Ion substitutions of Sr, Mg and Zn was carried out on HA for the first time by using Serratia grown in a defined biomineralization medium. The individual ions of varying concentration substituted in Serratia HA (SHA) (Sr SHA, Mg SHA and Zn SHA) were analysed for crystallinity, functional groups, morphology and crystal size. All three showed decreased crystallinity, phase purity, large agglomerated aggregates and needle-shaped morphologies. Fourier transform infrared spectroscopy (FTIR) spectra indicated increased carbonate content of 5.8% resembling that of natural bone. Additionally, the reduced O–H intensities clearly portrayed disruption of HA lattice and subsequent ion-substitution. The novelty of this study lies primarily in investigating the co-substitution of a combination of 1% Sr, Zn and Mg in SHA and establishing the associated change in bone parameters. Scanning electron microscope (SEM) and transmission electron microscope (TEM) images clearly illustrated uniform nano-sized agglomerates of average dimensions of 20–50 nm length and 8–15 nm width for Sr SHA; 10–40 nm length and 8–10 nm width for both Zn SHA and Mg SHA and 40–70 nm length and 4–10 nm width in the case of 1% Sr, Zn, Mg SHA. In both individual as well as co-substitutions, significant peak shifts were not observed possibly due to the lower concentrations. However, cell volumes increased in both cases due to presence of Sr2+ validating its dominant integration into the SHA lattice. Rich trace ion deposition was presented by energy dispersive X-ray spectroscopy (EDS) and quantified using inductively coupled plasma optical emission spectrometer (ICP-OES). In vitro cytotoxicity studies in three cell lines viz. NIH/3T3 fibroblast cells, MG-63 osteosarcoma cells and RAW 264.7 macrophages showed more than 90% cell viability proving the biocompatible nature of 1% Sr, Zn and Mg in SHA. Microbial biomineralization by Serratia produced nanocrystals of HA that mimicked “bone-like apatite” as evidenced by pure phase, carbonated groups, reduced crystallinity, nano agglomerates, variations in cell parameters, rich ion deposition and non-toxic nature. Therefore ion-substituted and co-substituted biomineralized nano SHA appears to be a suitable candidate for applications in biomedicine addressing bone injuries and aiding regeneration as a result of its characteristics close to that of the human bone.

One-step electrochemical elaboration of SnO2 modified electrode for lead ion trace detection in drinking water using SWASV.

A facile method was proposed for the elaboration of an electrochemical sensor for heavy metal's trace detection by using square wave anodic stripping voltammetry (SWASV); this method is based on a simple anodic conversion of tin electrode into Sn/SnO2 modified electrode. Both electrochemical and physico-chemical techniques were used to confirm the modification process and better understand the electrode's behavior. Then, depending on the operating conditions, the response signal was studied and adjusted in order to obtain optimal sensor performance. When optimized, the proposed method reached a lowest detection limit (LOD) of 2.15μg L-1 (0.0104μM), and quantification limit (LOQ) of 5.36μg L-1 (0.0259μM), in linearity range between from 6.2 and 20.7μg L-1. Additionally, after having used the elaborated electrode for ten successive measurements, the repeatability remains very high with an RSD of approximately 5.3%; furthermore, ten other species appear to have very slight effect on Pb(II) detection. Finally, for the method validation, the proposed electrode was able to sense different lead concentration integrated in a local bottled spring water by showing recovery levels ranging from 103.8 to 108.4%.