Ion Chromatography as a Reference Method for Determination of Inorganic Ions in Water and Wastewater

Towards elevated perfluorooctanoic acid (PFOA) enrichment in water: Sequential liquid-liquid extraction pretreatment for ion chromatography detection

The widespread detection of perfluorooctanoic acid (PFOA) in the environment has raised significant concerns. The standard PFOA analytical method relies on expensive solid-phase extraction (SPE) and liquid chromatography tandem mass spectrometry (LC-MS/MS) instruments, making routine use prohibitive. We herein proposed a cost-effective yet novel enrichment method for determining PFOA at ng L-1 level. This method entailed a two-step sample preparation process: firstly, PFOA was extracted and enriched using a forward-extraction under acidic conditions, followed by a backward-extraction and enrichment step utilizing alkaline water. The enriched samples were subsequently subjected to a common ion chromatography (IC). Results reveal that maintaining a forward-extraction pH below its pKa value (2.8) is essential, as protonated PFOA proves effective in enhancing the enrichment factor (EF). The challenge lied in driving PFOA from forward-extractant to aqueous backward-extractant due to the decreased hydrophobicity of deprotonated PFOA (log Kow2 = 1.0). In addition, we found that evaporating forward-extractant with alkaline backward-extractant (containing 5% methanol) reduced potential analytical uncertainties associated with PFOA evaporation and sorption. Under optimal conditions, the method achieved a detection limit of 9.2 ng L-1 and an impressive EF value of 719. Comparison with SPE-LC-MS/MS confirmed the proposed method as a promising alternative for PFOA determination. Although initially targeted for PFOA, the novel methodology is likely applicable to preconcentration of other poly-fluoroalkyl substances.

Transformation of Mercurous [Hg(I)] Species during Laboratory Standard Preparation and Analysis: Implication for Environmental Analysis

Hg(I) may control Hg redox kinetics; however, its metastable nature hinders analysis. Herein, the stability of Hg(I) during standard preparation and analysis was studied. Gravimetric analysis showed that Hg(I) was stable in its stock solution (1000 mg L-1), yet completely disproportionated when its dilute solution (10 μg L-1) was analyzed using liquid chromatography (LC)-ICPMS. The Hg(I) dimer can form through an energetically favorable comproportionation between Hg(0) and Hg(II), as supported by density functional theory calculation and traced by the rapid isotope exchange between 199Hg(0)aq and 202Hg(II). However, the separation of Hg(0) and Hg(II) (e.g., LC process) triggered its further disproportionation. Polypropylene container, increasing headspace, decreasing pH, and increasing dissolved oxygen significantly enhanced the disproportionation or redox transformations of Hg(I). Thus, using a glass container without headspace and maintaining a slightly alkaline solution are recommended for the dilute Hg(I) stabilization. Notably, we detected elevated concentrations of Hg(I) (4.4-6.1 μg L-1) in creek waters from a heavily Hg-polluted area, accounting for 54-70% of total dissolved Hg. We also verified the reductive formation of Hg(I) in Hg(II)-spiked environmental water samples, where Hg(I) can stably exist in aquatic environments for at least 24 h, especially in seawater. These findings provide mechanistic insights into the transformation of Hg(I), which are indicative of its further environmental identification.

Universal ion chromatography method for anions in active pharmaceutical ingredients enabled by computer-assisted separation modeling

Ion Chromatography (IC) is one of the most widely used methods for analyzing ionic species in pharmaceutical samples. A universal IC method that can separate a wide range of different analytes is highly desired as it can save a lot of time for method development and validation processes. Herein we report the development of a universal method for anions in active pharmaceutical ingredients (APIs) using computer-assisted chromatography modeling tools. We have screened three different IC columns (Dionex IonPac AS28-Fast 4 µm, AS19 4 µm and AS11-HC 4 µm) to determine the best suitable column for universal IC method development. A universal IC method was then developed using an AS11-HC 4 µm column to separate 31 most common anionic substances in 36 mins. This method was optimized using LC Simulator and a model which precisely predicts the retention behavior of 31 anions was established. This model demonstrated an excellent match between predicted and experimental analyte retention time (R2 =0.999). To validate this universal IC method, we have studied the stability of sulfite and sulfide analytes in ambient conditions. The method was then validated for a subset of 29 anions using water and organic solvent/water binary solvents as diluents for commercial APIs. This universal IC method provides an efficient and simple way to separate and analyze common anions in APIs. In addition, the method development process combined with LC simulator modeling can be effectively used as a starting point during method development for other ions beyond those investigated in this study.

Development of a Method for Multisensory Stripping Voltammetry in the Analysis of Medical Preparations

For the effective dosage of newly developed ophthalmic drugs, an assessment of the dynamics of their concentration in lacrimal fluid over time is required. To express the detection and identification of drugs, new methods are needed that must meet numerous requirements, not the least of which are selectivity, speed, the absence of false-negative results, and cost-effectiveness. The possibility of identifying anesthetics (sevoflurane) in lacrimal fluid has been studied using a new electrochemical method of multisensory inversion voltammetry in the electronic tongue and electronic nose format. The measurements were performed on a planar electrode, which is a three-electrode structure. The solution of the test system consisted of 0.05 M KCl, which contained the metal cations Zn2+, Cd2+, Pb2+, Co2+, and Hg2+ at a concentration of 5 × 10-5 M. It is shown that this method is effective for the determination of anesthetics, and the dynamics of changes in their concentration over time are examined. This study aimed to research the behavioral pharmacokinetics in the lacrimal fluid of the opioid drug sevoflurane in pediatric ophthalmology using multisensory stripping voltammetry in patients during strabismus correction surgery. The dynamics of changes in their concentrations over time were examined. After the instillation of the anesthetics in patients, their concentrations in the tear fluid remained unchanged within 10 min. The list of organic substances that can be determined by multisensory stripping voltammetry has been extended. The class of organic substances determined by the method of multisensory inversion voltammetry has been expanded.

A submersible probe with in-line calibration and a symmetrical reference element for continuous direct nitrate concentration measurements

Current methods to monitor nitrate levels in freshwater systems are outdated because they require expensive equipment and manpower. Punctual sampling on the field or at a fixed measuring station is still the accepted monitoring procedure and fails to provide real-time estimation of nitrate levels. Continuous information is of crucial importance to evaluate the health of natural aquatic systems, which can strongly suffer from a nitrogen imbalance. We present here a nitrate-selective potentiometric probe to measure the analyte continuously without requiring maintenance or high-power consumption. Owing to a simple design where the sensors are located directly in contact with the sample, the need for constant pump usage is eliminated, requiring just 0.7 mW power per day instead of 184 mW per day and per pump. It is estimated that with this power consumption, the setup can easily run for more than 97 h on four simple Li-ion batteries. A simple in-line one-point calibration step was implemented to allow for drift correction. At the same time, a symmetrical design was used involving a second nitrate probe as a reference electrode placed in the calibrant compartment. This, combined with an in situ calibration step, allows one to quantify nitrate ion concentrations directly, instead of yielding activities. The dependence on ion activity was removed by using the analysed sample spiked with nitrate as the calibrant. This results in essentially the same activity coefficients and additionally reduces junction potentials to a fraction of a millivolt. In addition, a symmetrical reference element served to compensate for fluctuations caused by environmental factors (temperature, convection, etc.) to achieve improved stability and signal reproducibility compared to a traditional Ag/AgCl based reference electrode. The final prototype was deployed in the Arve River in Geneva for 75 h without requiring any intervention. The nitrate levels measured using the symmetrical reference element over this period were estimated at 44.0 ± 3.5 M and agreed well with the values obtained with ion chromatography (38.2 ± 2.1 μM) used as the reference method. Thanks to a modular sensing head the potentiometric sensors can be easily exchanged, making it possible to quantify other types of analytes and leading the way to a new monitoring strategy.

Applications of two-dimensional ion chromatography for analytes determination in environmental matrix: A review

Ion chromatography (IC) has grown in usage rapidly since its first introduction in 1975. However, IC is still sometimes unable to separate target analytes from coexisting components well with identical elution time, due to the limited resolution and column capacity, especially in the presence of high-level salt matrix. These limitations hence drive IC to develop two-dimensional IC (2D-IC). In this review, we capture the 2D-IC applications in environmental samples via the perspective of coupling different IC columns, which aim to summarize where these 2D-IC methods fit in. In sequence, we firstly review the principles of 2D-IC and emphasize one-pump column-switching IC (OPCS IC) because it is a simplified 2D-IC that only uses one set of IC system. We then compare typical 2D-IC and OPCS IC performances in terms of application scope, method detection limit, drawbacks, and expectations. Finally, we propose some challenges of current methods and opportunities for future research. For instance, it is challenging to couple anion exchange column and capillary column in OPCS IC due to the incompatibility between flow path dimensions and suppressor; coupling ion exclusion column and mixed-bed column may be promising to simultaneously determine anions and cations in weak acids or salts. The details of this study may help practitioners to better understand and implement 2D-IC methods and meanwhile motivate researchers to fill in the knowledge gap in the future.

Determination of Inorganic Ions in Parenteral Nutrition Solutions by Ion Chromatography

A new, simple and sensitive ion chromatography (IC) method for the determination of sodium, potassium, magnesium, calcium and chloride in a parenteral nutrition (PN) solution was developed and validated. Before sample analysis, a sample pretreatment by calcination was applied which could totally remove interference from other constituents of the PN solution. Methanesulfonic acid (MSA) and sodium hydroxide were used as the mobile phase for the determination of cations and anions, respectively. The calibration curves showed good correlation between analyte peak area and concentration (r2 > 0.999). Detection limits ranged from 0.0001 to 0.02 mg/L and quantification limits from 0.0002 to 0.06 mg/L. Relative standard deviation (RSD) values for repeatability and inter-day precision did not exceed 1.0% and the recoveries for all analytes were between 99.1−101.1%. The robustness was verified by using an experimental design.

Removal of Scale-Forming Ions and Oil Traces from Oil Field Produced Water Using Graphene Oxide/Polyethersulfone and TiO2 Nanoribbons/Polyethersulfone Nanofiltration Membranes

Treatment of produced water in oil fields has become a tough challenge for oil producers. Nanofiltration, a promising method for water treatment, has been proposed as a solution. The phase inversion technique was used for the synthesis of nanofiltration membranes of polyethersulfone embedded with graphene oxide nanoparticles and polyethersulfone embedded with titanium nanoribbons. As a realistic situation, water samples taken from the oil field were filtered using synthetic membranes at an operating pressure of 0.3 MPa. Physiochemical properties such as water flux, membrane morphology, flux recovery ratio, pore size and hydrophilicity were investigated. Additionally, filtration efficiency for removal of constituent ions, oil traces in water removal, and fouling tendency were evaluated. The constituent ions of produced water act as the scaling agent which threatens the blocking of the reservoir bores of the disposal wells. Adding graphene oxide (GO) and titanium nanoribbons (TNR) to polyethersulfone (PES) enhanced filtration efficiency, water flux, and anti-fouling properties while also boosting hydrophilicity and porosity. The PES-0.7GO membrane has the best filtering performance, followed by the PES-0.7TNR and pure-PES membranes, with chloride salt rejection rates of 81%, 78%, and 35%; oil rejection rates of 88%, 85%, and 71%; and water fluxes of 85, 82, and 42.5 kg/m² h, respectively. Because of its higher hydrophilicity and physicochemical qualities, the PES-0.7GO membrane outperformed the PES-0.7TNR membrane. Nanofiltration membranes embedded with nanomaterial described in this work revealed encouraging long-term performance for oil-in-water trace separation and scaling agent removal.

The Green Microalga Coelastrella thermophila var. globulina (Scenedesmaceae, Chlorophyta) Isolated from an Algerian Hot Spring as a Potential Source of Fatty Acids

Screening microalgae from extreme environments, including hot springs, is an important research topic that has lately emerged. A thermophilic green alga was isolated from a north-eastern Algerian hot spring at a temperature of 63 °C, and its fatty acid (FA) profile was explored. The strain was cultivated in BBM medium at 35 °C in a 16:8 h light/dark cycle and 75 μM photons m⁻² s⁻¹. The morphological studies combined with phylogenetic analysis revealed that the isolate was Coelastrella thermophila var. globulina Q. Wang, H. Song, X. Liu, G. Liu and Z. Hu. The monounsaturated fatty acid (MUFA) content was 51.12%. The saturated fatty acid (SFA) and polyunsaturated fatty acid (PUFA) content, respectively, accounted for 27.01% and 21.87%. The main FA was oleic acid (18:1n–9), whose value was 35.95%, followed in decreasing order by palmitic acid (16:0) with 21.45%, linoleic acid (18:2n–6) with 14.38% and α-linolenic acid (18:3n–3) with 04.22%. The FA profile exhibited high total n–6 and n–3 PUFA values (15.80% and 5.76%, respectively). Coelastrella thermophila var. globulina is particularly interesting for producing n-6 and n-3 PUFA and is likely suitable for other biotechnological purposes. This is the first time that this taxon has been reported in hot springs. Other species can be expected to be reported, which emphasises the importance of the biodiversity of extreme habitats.

Formation of stable imine intermediates in the coexistence of sulfamethoxazole and humic acid by electrochemical oxidation

The electrochemical degradation performance of sulfamethoxazole (SMX) was studied in the presence of humic acid (HA) by using a Ti/Ti₄O₇/β-PbO₂ anode. The electrochemical degradation efficiency of SMX decreased from 93.4% to 45.8% in 50 min after the addition of 25 mg L^-1 HA. The pseudo-first-order kinetic rate constant decreased by 71.4%, and the E_EO value increased from 63.8 Wh L^-1 to 90.9 Wh L^-1. HA and its degradation intermediates could compete for free radicals, especially for ·OH, with SMX. The analytical results obtained using UPLC-ESI-Q-TOF-MS showed that 18 degradation intermediates were identified in the coexistence of SMX and HA. Four imine intermediates were formed through the reactions between the aniline moieties of SMX and quinone groups in the HA structure through covalent bonds. Furthermore, the relative abundances of the intermediates demonstrated that the imine intermediates were complex and stable during electrochemical degradation.

Green Aspects of Ion Chromatography versus Other Methods in the Analysis of Common Inorganic Ions

Due to the increasing environmental awareness of the public, green chemistry has become an important element of environmental protection. In laboratories around the world, millions of analyses of inorganic and organic anions and cations in water and wastewater samples, and solid and gaseous samples are performed daily. Unfortunately, these activities still generate large costs, including environmental costs, which are related to the scale of the studies, the use of toxic chemical reagents, the waste generated, and the energy consumed. The methods used so far for inorganic ion analysis, including classical methods, are increasingly being replaced by instrumental methods, primarily based on ion chromatography. This paper presents the most important advantages and limitations of ion chromatography, and compares them with the costs of classical analyses for the analytes and sample types. Both the financial and environmental costs associated with the determination of common inorganic ions, such as Cl−, NO2−, NO3−, and NH4+, in 1000 environmental samples, were compared using selected reference wet classical methods and ion chromatography. The advantages and limitations of ion chromatography that allow this separation technique to be classified as a green analytical chemistry method have been described herein.

Determination of ammonium and biogenic amines by ion chromatography. A review

The amount and type of chemical compounds found in food products and the environment, which are and should be controlled, is increasing. This is associated with toxicological knowledge, resulting regulations, rapid development of analytical methods and techniques, and sample preparation methods for analysis. These include, among others, ammonia derivatives such as ammonium, and amines, including biogenic amines. Their occurrence in the environment and food is related to their widespread use in many areas of life and their formation as a result of various physical and chemical changes. Analysts use various methods both classical and instrumental to theirs quantify in different matrices such as food, medicinal and environmental samples. Nevertheless, there is still a need for analytical methods with increased matrix-tolerance, selectivity, specificity, and higher sensitivity. While in the determination of ammonium, ion chromatography is a reference method. In the case of biogenic amines, its use for these purposes is not yet so common. However, given ion chromatography its advantages and rapid development, its importance can be expected to increase in the near future, especially at the expense of gas chromatography methods. This paper is a summary of the advantages and limitations of ion chromatography in this important analytical field and a literature review of the past 15 years.

Effects of valinomycin doping on the electrical and structural properties of planar lipid bilayers supported on polyelectrolyte multilayers

Supported Lipid Bilayers (SLBs) on Polyelectrolyte Multilayers (PEMs) have large potential as models for developing sensor devices. SLBs can be designed with receptors and channels, which benefit from the biological environment of the lipid layers, to create a sensing interface for ions and biomarkers. PEMs assembled by the Layer-by-Layer (LBL) technique and used as supports for a lipid bilayer enable an easy integration of the bilayer on almost any surface and device. For electrochemical sensors, LBL assembly enables nanoscale tunable separation of the lipid bilayer from the electrode surface, avoiding undesired effects of the electrode surface on the lipid bilayers. We study the fabrication of valinomycin-doped SLBs on PEMs as a model system for biophysical studies and for selective ion sensing. SLBs are fabricated from dioleoylphosphatidylcholine (DOPC) and dioleoylphosphatidylserine (DOPS) 50:50 vesicles doped with valinomycin, as a K⁺-selective carrier. SLBs were deposited on electrodes coated with poly(allyl amine hydrochloride) (PAH) and poly(styrene sodium sulfonate) (PSS) multilayers. Lipid bilayer formation was monitored by using Quartz Crystal Microbalance with Dissipation (QCMD) technique and Atomic Force Microscopy (AFM). Electrochemical impedance spectroscopy (EIS) and potentiometric measurements were performed to assess K⁺ selectivity over other ions and the potential of valinomycin-doped SLBs for K⁺-sensing.

Utilization of a Crown Ether/Amine-Type Rotaxane as a Probe for the Versatile Detection of Anions and Acids by Thin-Layer Chromatography

A crown ether/amine-type [2]rotaxane was synthesized and utilized as a probe for the detection of acids and anions. The addition of acids to the amine-type [2]rotaxane solution generated corresponding crown ether/ammonium-type [2]rotaxanes, which were purified by silica gel column chromatography as ammonium salts. The isolated yields of the [2]rotaxanes, possessing a variety of anions, depended on the acidity and polarity of the counter anions. The behaviours of the ammonium-type [2]rotaxanes on thin-layer chromatography (TLC) silica gel reflected the properties of the counter anions. The treatment of the amine-type [2]rotaxane with acids afforded the corresponding ammonium-type [2]rotaxanes bearing several different anions. The ammonium-type [2]rotaxanes behaved similarly to the purified [2]rotaxanes on the TLC silica gel. Furthermore, we succeeded in the analysis of anions using mixtures of the amine-type [2]rotaxane and salts in an appropriate solvent. We demonstrated the detection of anions by the combination of TLC and the utilization of the [2]rotaxane probe.

Ion Chromatography and Related Techniques in Carboxylic Acids Analysis

Ion chromatography (IC) is a variant of high-performance liquid chromatography. Its most important applications include the determination of inorganic and some organic ions in different types of liquid samples. The development of new types of stationary phases with various separation mechanisms, sample preparation methods, and detection modes has extended ion chromatography applications to practically all ionic and ionogenic substances, as well as extending sample types to include gaseous and solid matrices. Carboxylic acids and their derivatives are examples of compounds that are becoming more frequently analyzed using ion chromatography and related techniques. Their occurrence in the environment can be natural or anthropogenic in origin and are broadly used in various industries and daily life. This article discusses the applications of ion chromatography and related techniques for the determination of carboxylic acids in different types of liquid, solid, and gaseous matrices. It also presents detailed methodologies and literature data on this subject from the last 15 years.

Field Scale Mobility and Transport Manipulation of Carbon-Supported Nanoscale Zerovalent Iron in Fractured Media

In field applications, mostly in porous media, transport of stabilized nano zerovalent iron particles (nZVI) has never exceeded a few meters in range. In the present study, the transport of Carbo-Iron Colloids (CIC), a composite material of activated carbon as a carrier for nZVI stabilized by carboxymethyl cellulose (CMC), was tested under field conditions. The field site lies within a fractured chalk aquitard characterized by moderately saline (∼13 mS) groundwater. A forced gradient tracer test was conducted where one borehole was pumped at a rate of 8 L/min and CMC-stabilized CIC was introduced at an injection borehole 47 m up-gradient. Two CIC-CMC field applications were conducted: one used high 100% wt CMC (40 g/L) and a second used lower 9% wt loading (∼2.7 g/L). Iodide was injected as a conservative tracer with the CIC-CMC in both cases. The ratio between the CIC-CMC and iodide recovery was 76% and 45% in the high and low CMC loading experiments, respectively. During the low CMC loading experiment, the pumping rate was increased, leading to an additional CIC recovery of 2.5%. The results demonstrate the potentially high mobility of nZVI in fractured environments and the possibility for transport manipulation through the adjustment of stabilizer concentration and transport velocity.

Inorganic elemental analysis of decomposition fluids of an in situ animal burial

In homicide investigations, it is critically important that post-mortem (PMI) and post-burial interval (PBI) of buried victims are determined accurately. However, clandestine graves can be difficult to locate; and the detection rates for a variety of search methods can be very low. This paper presents elemental analysis results of 18 months of decomposition fluids from an in situ buried animal cadaver used as a human clandestine burial proxy. Study results showed potassium, sulphate and sodium are key detectable elements which mirror observed conductivity temporal changes from this and other studies. Seasonal rainfall has a strong influence on both fluid generation and subsequent concentration which needs to be accounted for. Study implications suggest inorganic elements could provide both detection and potential dating of discovered clandestine burials.

Validating a High Performance Liquid Chromatography-Ion Chromatography (HPLC-IC) Method with Conductivity Detection After Chemical Suppression for Water Fluoride Estimation

A variety of methods, including the Ion Selective Electrode (ISE), have been used for estimation of fluoride levels in drinking water. But as these methods suffer many drawbacks, the newer method of IC has replaced many of these methods. The study aimed at (1) validating IC for estimation of fluoride levels in drinking water and (2) to assess drinking water fluoride levels of villages in and around Vellore district using IC. Forty nine paired drinking water samples were measured using ISE and IC method (Metrohm). Water samples from 165 randomly selected villages in and around Vellore district were collected for fluoride estimation over 1 year. Standardization of IC method showed good within run precision, linearity and coefficient of variance with correlation coefficient R² = 0.998. The limit of detection was 0.027 ppm and limit of quantification was 0.083 ppm. Among 165 villages, 46.1% of the villages recorded water fluoride levels >1.00 ppm from which 19.4% had levels ranging from 1 to 1.5 ppm, 10.9% had recorded levels 1.5-2 ppm and about 12.7% had levels of 2.0-3.0 ppm. Three percent of villages had more than 3.0 ppm fluoride in the water tested. Most (44.42%) of these villages belonged to Jolarpet taluk with moderate to high (0.86-3.56 ppm) water fluoride levels. Ion Chromatography method has been validated and is therefore a reliable method in assessment of fluoride levels in the drinking water. While the residents of Jolarpet taluk (Vellore distict) are found to be at a high risk of developing dental and skeletal fluorosis.

Determination of Inorganic Cations and Anions in Chitooligosaccharides by Ion Chromatography with Conductivity Detection

Chitooligosaccharides (COSs) are a promising drug candidate and food ingredient because they are innately biocompatible, non-toxic, and non-allergenic to living tissues. Therefore, the impurities in COSs must be clearly elucidated and precisely determined. As for COSs, most analytical methods focus on the determination of the average degrees of polymerization (DPs) and deacetylation (DD), as well as separation and analysis of the single COSs with different DPs. However, little is known about the concentrations of inorganic cations and anions in COSs. In the present study, an efficient and sensitive ion chromatography coupled with conductivity detection (IC-CD) for the determination of inorganic cations Na⁺, NH₄⁺, K⁺, Mg²⁺, Ca²⁺, and chloride, acetate and lactate anions was developed. Detection limits were 0.01-0.05 μM for cations and 0.5-0.6 μM for anions. The linear range was 0.001-0.8 mM. The optimized analysis was carried out on IonPac CS12A and IonPac AS12A analytical column for cations and anions, respectively, using isocratic elution with 20 mM methanesulfonic acid and 4 mM sodium hydroxide aqueous solution as the mobile phase at a 1.0 mL/min flow rate. Quality parameters, including precision and accuracy, were fully validated and found to be satisfactory. The fully validated IC-CD method was readily applied for the quantification of various cations and anions in commercial COS technical concentrate.

Cytotoxicity, Genotoxicity, and Phytotoxicity of Tannery Effluent Discharged into Palar River Basin, Tamil Nadu, India

Ambur, a town located on the banks of Palar River, is considered one of the most polluted areas in India and occupied by hundreds of tanneries and leather product units. The present study was designed to evaluate the toxic effect of discharged tannery effluent (TE) on model agricultural crops, ecofriendly microorganisms, and human blood cells. The phytotoxic effects of TE tested on Allium cepa and Lemna minor revealed inhibition of root growth and significant reduction in number of fronds, protein, and chlorophyll content. Moreover, TE induced chlorosis and tissue necrosis in Nostoc muscorum at low concentration (10%). TE has also negative impact on ecofriendly microorganisms, Bacillus thuringiensis, Rhizobium etli, and Aspergillus terreus which play an important role in the nutrition of plant growth. The genotoxicity of TE was investigated in human leukocytes which showed interference with normal mitotic division with subsequent cell lysis. It also intervened with the normal replication process and induced micronucleus formation in the healthy leukocyte. 5% concentration of TE has been revealed to be toxic to erythrocytes. From this study TE found in the Palar River of Ambur has adverse effects on all the three levels of organisms in ecosystem even at lower concentrations.

Chemometric and environmental assessment of arsenic, antimony, and chromium speciation form occurrence in a water reservoir subjected to thermal anthropopressure

In the study, arsenic, antimony, and chromium concentrations and selected physicochemical parameters in water and sediment samples from the thermal anthroporessure subjected Rybnik Reservoir (Poland) were determined. As(III), As(V), Sb(III), and Sb(V) ions were successfully separated on Dionex IonPac AS7 column, and Cr(III) and Cr(VI) on Dionex IonPac AG7 column. The obtained limits of detection were 0.18, 0.22, 0.009, 0.012, 0.11, and 0.17 μg/L, respectively. Water and bottom sediment samples were collected monthly at three-point transect between January and November 2013. The As(III) and Sb(III) speciation forms dominated in the bottom water, and Cr(VI) concentration in the bottom water was twice as high as the value measured for the surface water. The oxidized arsenic, antimony, and chromium forms dominated in the bottom sediments in the heated water discharge zone of the Rybnik Power Plant. The location of sampling point had a significant influence on the observed transformations and contents of the analyzed speciation forms. The chemometric analysis coupled with the dissimilarity analysis and principal component analysis helped to visualize the variability in the concentrations of the element speciation forms within the researched period and analyzing correlations.

Advanced analytical methods and sample preparation for ion chromatography techniques

The recently developed advanced ion chromatography techniques and the various sample preparation methods have been summarized in this mini-review.

Combined effects of lanthanum(III) and elevated ultraviolet-B radiation on root growth and ion absorption in soybean seedlings

Rare earth element accumulation in the soil and elevated ultraviolet (UV)-B radiation (280-315 nm) are important environmental issues worldwide. To date, there have been no reports concerning the combined effects of lanthanum (La)(III) and elevated UV-B radiation on plant roots in regions where the two issues occur simultaneously. Here, the combined effects of La(III) and elevated UV-B radiation on the growth, biomass, ion absorption, activities, and membrane permeability of roots in soybean (Glycine max L.) seedlings were investigated. A 0.08 mmol L(-1) La(III) treatment improved the root growth and biomass of soybean seedlings, while ion absorption, activities, and membrane permeability were obviously unchanged; a combined treatment with 0.08 mmol L(-1) La(III) and elevated UV-B radiation (2.63/6.17 kJ m(-2) day(-1)) exerted deleterious effects on the investigated indices. The deleterious effects were aggravated in the other combined treatments and were stronger than those of treatments with La(III) or elevated UV-B radiation alone. The combined treatment with 0.24/1.20 mmol L(-1) La(III) and elevated UV-B radiation exerted synergistically deleterious effects on the growth, biomass, ion absorption, activities, and membrane permeability of roots in soybean seedlings. In addition, the deleterious effects of the combined treatment on the root growth were due to the inhibition of ion absorption induced by the changes in the root activity and membrane permeability.

Ion-specific nutrient management in closed systems: the necessity for ion-selective sensors in terrestrial and space-based agriculture and water management systems

The ability to monitor and control plant nutrient ions in fertigation solutions, on an ion-specific basis, is critical to the future of controlled environment agriculture crop production, be it in traditional terrestrial settings (e.g., greenhouse crop production) or as a component of bioregenerative life support systems for long duration space exploration. Several technologies are currently available that can provide the required measurement of ion-specific activities in solution. The greenhouse sector has invested in research examining the potential of a number of these technologies to meet the industry's demanding requirements, and although no ideal solution yet exists for on-line measurement, growers do utilize technologies such as high-performance liquid chromatography to provide off-line measurements. An analogous situation exists on the International Space Station where, technological solutions are sought, but currently on-orbit water quality monitoring is considerably restricted. This paper examines the specific advantages that on-line ion-selective sensors could provide to plant production systems both terrestrially and when utilized in space-based biological life support systems and how similar technologies could be applied to nominal on-orbit water quality monitoring. A historical development and technical review of the various ion-selective monitoring technologies is provided.

Determination of ammonium, calcium, magnesium, potassium and sodium in drinking waters by capillary zone electrophoresis on a column-coupling chip

This work deals with simultaneous determination of ammonium, calcium, magnesium, sodium and potassium in drinking waters by capillary zone electrophoresis (CZE) on a column-coupling (CC) chip with suppressed hydrodynamic and electroosmotic transports. CZE separations were carried out in a propionate background electrolyte at a low pH (3.2) containing 18-crown-6-ether (18-crown-6) to reach a complete resolution of the cations. In addition, triethylenetetramine (TETA) coated the inner wall surface of the chip channels. The concentration limits of detection (cLOD) for the studied cations ranged from 4.9 to 11.5 microg/l concentrations using a 900 nl volume of the sample injection channel. 93-106% recoveries of the cations in drinking waters indicate a good predisposition of the present method to provide accurate analytical results.

Methane and nitrous oxide fluxes in the polluted Adyar River and estuary, SE India

We measured dissolved N(2)O, CH(4), O(2), NH(4)(+), NO(3)(-) and NO(2)(-) on 7 transects along the polluted Adyar River-estuary, SE India and estimated N(2)O and CH(4) emissions using a gas exchange relation and a floating chamber. High NO(2)(-) implied some nitrification of a large anthropogenic NH(4)(+) pool. In the lower catchment CH(4) was maximal (6.3+/-4.3 x 10(4)nM), exceeding the ebullition threshold, whereas strong undersaturation of N(2)O and O(2) implied intense denitrification. Emissions fluxes for the whole Adyar system approximately 2.5 x 10(8) g CH(4)yr(-1) and approximately 2.4 x 10(6)gN(2)O yr(-1) estimated with a gas exchange relation and approximately 2 x 10(9) g CH(4)yr(-1) derived with a floating chamber illustrate the importance of CH(4) ebullition. An equivalent CO(2) flux approximately 1-10 x 10(10)gy r(-1) derived using global warming potentials is equivalent to total Chennai motor vehicle CO(2) emissions in one month. Studies such as this may inform more effective waste management and future compliance with international emissions agreements.

Simultaneous determination of fluoride and monofluorophosphate in toothpastes by supressed ion chromatography

Suppressed ion chromatography with a highly selective and high capacity anion-exchange column is used for the determination of anionic compounds in ten commercially available toothpastes. Minimal sample preparation is needed, requiring only dilution and filtration over a solid-phase extraction cartridge. Quantitative analysis of fluoride and monofluorophosphate, as well as chloride, nitrate, orthophosphate, and sulfate is achieved in one chromatographic run with a total analysis time of 25 minutes.

Optimized analytical conditions are validated in terms of accuracy, precision, and total uncertainty, and the results demonstrate the reproducibility of ion chromatography. The coefficient of determination for the anions ranges from 0.9896 to 0.9997. The spiked recoveries for the anions are 88–108%. The change in the fluoride content of the toothpaste with storage time is investigated.