Rapid separation of post‐blast explosive residues on glass electrophoresis microchips

This study describes the development of an analytical methodology based on the use of microchip electrophoresis (ME) devices integrated with capacitively coupled contactless conductivity detection (C⁴D) for the separation and detection of inorganic anions in post‐blast explosive residues. The best separation condition was achieved using a running buffer composed of 35 mmol/L lactic acid, 10 mmol/L histidine and 0.070 mmol/L cetyl(trimethyl ammonium) bromide. For C⁴D measurements, the highest sensitivity was obtained applying a 700 kHz sinusoidal wave with excitation voltage of 20 V_pp. The separation of Cl^?, NO₃^?, NO₂^?, SO₄^2?, ClO₄^? and ClO₃^? was performed within ca. 150 s with baseline resolution and efficiencies between 4.4 × 10⁴ and 1.7 × 10⁵ plates/m. The found limits of detection ranged between 2.5 and 9.5 μmol/L. Last, real samples of post‐blast explosive residues were analyzed on the ME‐C⁴D devices obtaining successfully the determination of Cl^?, NO₃^? and SO₄^2?. The achieved concentration values varied between 12.8–72.5 mg/L for Cl^?, 1.7–293.1 mg/L for NO₃^? and 1.3–201.3 mg/L for SO₄^2?. The data obtained using ME‐C⁴D devices were in good agreement with the concentrations found by ion chromatography. The approach reported herein has provided short analysis time, instrumental simplicity, good analytical performance and low cost. Furthermore, the ME‐C⁴D devices emerge as a powerful and portable analytical platform for on‐site analysis demonstrating to be a promising tool for the crime scene investigation.     

Naked Eye Detection of Carbonate,Hydroxide, and Cyanide Ions with 1,4′‐Diazaflavonium Bromides: A Simple Spectrophotometric Method for Cyanide Determination

Anion sensor properties of N‐alkyl‐substituted 1,4′‐diazaflavonium bromides in methanol–water were evaluated by UV–vis spectrometry. Pronounced changes were observed in the absorption spectra of all compounds for only OH^?, CO₃^2?, and CN^? among F^?, Cl^?, Br^?, I^?, OH^?, CO₃^2?, NO₃^?, PO₄^3?, CN^?, SO₄^2?, HSO₄^?, HCO₃^?, SCN^?, NO₂^?, and P₂O₇^2? ions. Two new absorption bands at 385 and 685 nm accompanying the distinct color change for OH^?, CO₃^2?, and CN^? ions were observed in case of all compounds. The color changes were from pink to blue for CO₃^2? and OH^? ions and from pink to purple for CN^? ion. Thanks to the distinct color change, the compounds can be used as selective colorimetric anion sensors. Linear changes of absorbance of N‐heptyl‐substituted compound at 385 nm as a function of the ion concentration were used to determine CN^? ion in water samples. Detection and quantification limits of the proposed method were 0.94 and 2.82 mg/L, respectively.     

The Cloud Point Behaviors and the Liquid–Liquid Equilibrium of L31—Inorganic Sodium Salt Aqueous Two-Phase Systems

The cloud point (CP) of triblock-copolymer L31 aqueous solution was determined with salting-out salts (Na₂SO₄/Na₂CO₃/NaF/NaCl/NaBr). The results show that all these salts can decrease the CP of L31 aqueous solution and form aqueous two-phase system (ATPS). With increasing concentrations of Na₂SO₄ and Na₂CO₃, an obvious phase inversion could be observed and phase inversion points were found. This was mainly due to the change in density, the salt-rich phase shifted from the top phase to the bottom phase. Meanwhile, the liquid-liquid equilibrium (LLE) data for L31-Na₂SO₄/Na₂CO₃/NaF/NaCl/NaBr ATPSs were measured at 288.15 K. The salt ability to decrease the CP and to induce the phase separation is as follows: Na₂SO₄?>?Na₂CO₃, NaF?>?NaCl?>?NaBr. Finally, the order of anions that reduced the CP and caused phase separation was obtained as follows: SO₄^2? >CO₃^2?, F^??>?Cl^??>?Br^?.     

Ion Chromatographic Determination of Anions in Environmental Samples

Abstract

The use of ion-exchange chromatography with an IonPac AS 14 column, 3.5 mM Na₂CO₃/1.0 mM NaHCO₃ eluent and suppressed conductivity detection provides a simple, cost-effective, fast, accurate, and highly sensitive method for the determination of F^?, Cl^?, NO₂ ^?, Br^?, NO₃ ^?, PO₄ ^2?, SO₄ ^2?, and C₂O₄ ^2? at low μ/L levels in environmental samples. Data on sensitivity, selectivity, accuracy, and % relative standard deviation are described. The method is suitable for many environmental applications including atmospheric aerosols (exposed on cellulose, glass fiber, and quartz filters), rainwater, cloud water, potable- and non-potable waters, and carbonated waters. Dominant components of the aerosol were SO₄ ^2?, NO₃ ^?, and Cl^?. Rainwater, on the other hand, has relatively very low concentrations of these three species. The wide-spread concentration range for Cl^? in variety of water samples and the high concentrations for SO₄ ^2? in drinking water are striking. Determination of the anionic composition of carbonated waters revealed a considerable variation of the individual anions.     

Effect of Inorganic Ions on the Oxidation of Methyl Violet with Gliding Arc Plasma Discharge

Gliding arc discharge process was used for the treatment of methyl violet wastewater. First, the intermediate products were studied by gas chromatography coupled with mass spectrometry and Fourier transform infrared spectrometry, and ultraviolet–visible spectrometer. Second, the effects of inorganic anions including chloride (Cl^?), carbonate (CO₃ ^2?), sulfate (SO₄ ^2?), phosphate (PO₄ ^3?), nitrate (NO₃ ^?) on the degradation efficiency of methyl violet were examined. The research results indicated that hydroxyl radicals attacked carbon atom that situated in the center of dye molecule, and the conjugating structure of methyl violet was destroyed, and dye was degraded and decolored, so a possible degradation pathway was proposed by the analysis of intermediate products detected. The methyl violet degradation rate decreased with increasing anions concentrations, and their order of sequence according to the inhibition reaction was CO₃ ^2? > Cl^? > SO₄ ^2? > NO₃ ^?.     

Simultaneous speciation analysis of inorganic nitrogen with the use of ion chromatography in highly salinated environmental samples

We present the development of a method for the simultaneous determination of inorganic nitrogen species in oxidized (NO₂^–, NO₃^–) and reduced (NH₄⁺) forms using ion chromatography with diode‐array detection (205, 208, and 425 nm, respectively). The oxidized forms were determined directly after the separation in the anion exchanger, while the reduced form was determined in the column hold‐up time after derivatization with the Nessler reagent. The use of an appropriate modifier (Seignette reagent) and mobile phase (NaCl) enabled the determination of inorganic nitrogen species in highly salinated environmental samples (water, sediments). Moreover, low detection limits were obtained of 0.04 mg/L for NH₄⁺ and 0.006 and 0.005 mg/L for NO₂^– and NO₃^–, respectively. The analysis of environmental samples indicated NH₄⁺ contents of up to 1161 ± 47 mg/kg and NO₃^– of up to 148 ± 6 mg/kg for sediment samples, as well as the NH₄⁺ concentrations of up to 0.98 ± 0.10 mg/L, NO₂^– of up to 24 ± 1 mg/L and NO₃^– of up to 20 ± 1 mg/L for water samples.     

Simultaneous determination of chloride, nitrate and sulphate in vegetable samples by single-column ion chromatography

A new ion chromatography method is described for the simultaneous determination of Cl⁻, NO₃⁻ and SO₄²⁻, using a selected eluent 1.3-mM sodium gluconate/1.3-mM borax (pH 8.5). The extraction methods of Cl⁻, NO₃⁻, SO₄²⁻ in vegetables are studied. The determination limits of Cl⁻, NO₃⁻, SO₄²⁻ are 0.17 μg/ml, 0.63 μg/ml and 0.81 μg/ml. The linear ranges are 060 μg/ml, 090 μg/ml and 090 μg/ml. The relative S.D. are <2.5%. The mean recoveries of Cl⁻, NO₃⁻, SO₄²⁻ in vegetables range from 97.0 to 104%.     

Highly Selective Thiocyanate Electrode Based on Bis‐bebzion Schiff Base Binuclear Copper(II) Complex as Neutral Carrier

Abstract

A highly selective polyvinyl chloride (PVC) membrane electrode, based on N,N′‐(aminoethyl)ethylenediamide bis(2‐benzoideneimine) binuclear copper(II) complex [Cu(II)‐AEBB] as neutral carrier, was prepared for thiocyanate (SCN^?) determination, which displays an anti‐Hofmeister selectivity sequence for a series of anions in the following order: SCN^?>ClO₄ ^?>Sal^? > I^?>NO₃ ^?>Br^?> Cl^?>NO₂ ^?>SO₃ ^2?>F^?>H₂PO₄ ^?>SO₄ ^2?. The electrode exhibited near‐Nernst response for SCN^? with a slope of –59.0 mV/decade over a wide concentration range (8.5×10^?7～6.8×10^?1 mol/L) with a detection limit of –5.0×10^?7 mol/L in pH 5.0 phosphate buffer solution at 25°C. Alternating current (AC) impedance and equivalent circuits were used to investigate the thiocyanate response mechanism of the membrane doped with [Cu(II)‐AEBB].     

The extraction of thulium(III), dysprosium(III) and samarium(III) by dioctylarsinic acid in chloroform

Dioctylarsinic acid, HDOAA, in chloroform (0.1 M) extracts thulium(III), dysprosium(III) and samarium(III) from their aqueous solutions in the pH ranges 1–6.5, 2–7 and 4–8, respectively, with extraction coefficients of approximately 0.1 for the lowest and 10 for the highest pH. The extractability increased with increasing ionic strength for each ion and decreased in the order ClO₄^- > NO₃^- > Cl^- > SO₄^2- > acetate for solutions of the same molarity. pH-Dependence curves had slopes ranging from 1.05 to 1.87. The reagent-dependence studies gave curves with slopes between 3.60 and 5.30. The general formula [MX_n(DOAA)_m(HDOAA)_p(H₂O)_q] (X = Cl^-. NO₃^-, SO₄^2-/2, ClO₄^-, acetate, OH^-; n+m=3, m+p=4 or 5, q?0)is suggested for the extracted species.     

Visible Light Excitable SCN− Selective Fluorescence Probe Derived from Thiophene

An efficient fluorescence probe, 4‐methyl‐2,6‐bis((thiophen‐2‐ylmethylimino)methyl)phenol (DFPTMA) and its SCN^? adduct has been synthesized and characterized by different spectroscopic techniques like ¹H NMR,¹³C NMR, QTOF‐MS ES⁺, UV‐Vis and FTIR spectroscopy. Single crystal X‐ray structure of DFPTMA is reported. In presence of SCN^?, DFPTMA exhibits significant fluorescence enhancement (λ_Ex, 455 nm, λ_Em, 504 nm) in aqueous methanol (water‐methanol, 1:4, V/V, 0.1 mol/L HEPES buffer, pH 7.4). Common bio‐relevant anions viz. CH₃COO^?, NO₂^?, NO₃^?, Cl^?, Br^?, I^?, SO₄^2?, HSO₄^?, N₃^?, HAsO₄^2?, Cr₂O₇^2?, H₂PO₄^?, ClO₄^?, NCO^?, CN^?, CO₃^2?, F^?, PO₄^3?, S^2?, HS^? do not interfere in the recognition of SCN^?. Lowest detection limit for SCN^? is 0.88 µmol/L with response time <5 min. The SCN^? assisted enhancement in emission intensity may be attributed to the formation of H‐bond which enhances the rigidity of the molecular assembly.     

Use of Ionenes as Capillary Modifiers in the Simultaneous Determination of Azide, Chlorate, and Perchlorate Ions by Capillary Electrophoresis

It was demonstrated that Cl^–, SO₄ ^2-, NO₃ ^-, N₃ ^-, ClO₃ ^–, and ClO₄ ^– ions can be simultaneously and selectively determined by capillary electrophoresis using 2,4-ionene as a capillary modifier. The effect of n-butanol additives to the buffer electrolyte on the migration times of ions was shown. The optimum buffer electrolyte contained 0.5 mM Na₂CrO₄, 0.05% 2,4-ionene, 10%n-butanol, and 7% methanol. It was shown that azide can be identified in wash solutions obtained at the place of lead azide explosion. The detection limit for azide was 1–3 mg/L.     

Analysis of inorganic anions by electrostatic ion chromatography using zwitterionic/cationic mixed micelles as the stationary phase

The inability to separate fluoride, phosphate and sulfate by electrostatic ion chromatography (EIC) was overcome by using an ODS silica column coated with mixed zwitterionic-cationic surfactants as the stationary phase. The best results were obtained using the zwitterionic surfactant, 3-(N,N-dimethylmyristylammonium)-propanesulfonate (C₁₉H₄₁NO₃S), and the cationic surfactant, myristyltrimethylammonium, CH₃(CH₂)₁₃N⁺(CH₃)₃, in a 10:1 molar ratio in the column coating solution. With a dilute solution of sodium tetraborate as the eluent the model analyte anions were completely separated in the following elution order: F^–, HPO₄ ^2–, SO₄ ^2–, Cl^–, NO₂ ^–, Br^–, NO₃ ^–. The very early elution of phosphate and sulfate is most unusual and is unique to this system. Detection limits better than 1.1 × 10^–4 mM and linear calibration plots up to 7.0 mM were obtained with a suppressed conductivity system.     

A Series of Amino Acid Functionalized Tripodal Hexaamide Anion Receptors: Ion‐Pair‐Assisted Capped‐Cleft Formation by a Pentafluorophenyl‐Functionalized Amide

A new series of tris(2‐aminoethyl)amine (tren)‐based L ‐alanine amino acid backboned tripodal hexaamide receptors (L1–L5) with various attached moieties based on electron‐withdrawing fluoro groups and lipophilicity have been synthesized and characterized. Detailed binding studies of L1–L5 with different anions, such as halides (F^?, Cl^?, Br^?, and I^?) and oxyanions (AcO^?, BzO^? (Bz=benzoyl), NO₃^?, H₂PO₄^?, and HSO₄^?), have been carried out by isothermal titration calorimetric (ITC) experiments in acetonitrile/dimethylsulfoxide (99.5:0.5 v/v) at 298 K. ITC titration experiments have clearly shown that receptors L1–L4 invariably form 1:1 complexes with Cl^?, AcO^?, BzO^?, and HSO₄^?, whereas L5 forms a 1:1 complex only with AcO^?. In the case of Br^?, I^?, and NO₃^?, no appreciable heat change is observed owing to weak interactions between these anions and receptors; this is further confirmed by ¹H NMR spectroscopy. The ITC binding studies of F^? and H₂PO₄^? do not fit well for a 1:1 binding model. Furthermore, ITC binding studies also revealed slightly higher selectivity of this series of receptors towards AcO^? over Cl^?, BzO^?, and HSO₄^?. Solid‐state structural evidence for the recognition of Cl^? by this new category of receptor was confirmed by single‐crystal X‐ray structural analysis of the complex of tetrabutylammonium chloride (TBACl) and L1. Single‐crystal X‐ray diffraction clearly showed that the pentafluorophenyl‐functionalized amide receptor (L1) encapsulated Cl^? in its cavity by hydrogen bonds from amides, and the cavity of L1 was capped with a TBA cation through hydrogen bonding and ion‐pair interactions to form a capped‐cleft orientation. To understand the role of the cationic counterpart in solution‐state Cl^? binding processes with this series of receptors (L1–L4), a detailed Cl^? binding study was carried out with three different tetraalkylammonium (Me₄N⁺, Et₄N⁺, and Bu₄N⁺) salts of Cl^?. The binding affinities of these receptors with different tetralkylammonium salts of Cl^? gave binding constants with the TBA cation in the following order: butyl>ethyl>methyl. This study further supports the role of the TBA countercation in ion‐pair recognition by this series of receptors.     

Anion‐Directed Copper(II) Metallocages,Coordination Chain,and Complex Double Salt: Structures,Magnetic Properties,EPR Spectra,and Density Functional Study

A series of Cu^II metallo‐assemblies showing anion‐directed structural variations, including five metallocages [(G^n?)?{Cu₂(Hdpma)₄}]^(8?n)+(A^?)_8?n (G^n?=NO₃^?, ClO₄^?, SiF₆^2?, BF₄^?, SO₄^2?; A^?=NO₃^?, ClO₄^?, BF₄^?, CH₃SO₄^?; Hdpma=bis(3‐pyridylmethyl)ammonium cation), a complex double salt, namely, (H₃dpma)₄(CuCl₄)₅Cl₂, and a coordination chain, namely, [Cu₂(dpma)(OAc)₄], are reported. The influence of the anion can be explained by its coordinating ability, the affinity of which for the Cu^II center interferes significantly with metallocage formation, and its shape, which offers host–guest recognition ability to engage in weak metal–anion coordination and hydrogen bonding to the organic ligand, which are responsible for metallocage templation. EPR studies of these metallocages in the powder phase at room temperature and 77 K showed a trend of the g values (g_||>2.10>g_⊥>2.00) indicating a ‐based ground state with square‐pyramidal geometry for the Cu^II centers. The magnetism of these metallocages can be interpreted as the result of a combination of relatively small magnetic coupling integrals and a substantial contribution of temperature‐independent paramagnetism (TIP). The weak magnetic interaction is corroborated by the results of DFT calculations and the EPR spectra. Availability of the low‐lying state for spin population was confirmed by a magnetization study, which revealed a magnetic moment approaching 2Nβ, which would explain the presence of the larger TIP term.     

Three copper(II) complexes constructed from 4-(2-pyridyl)-<Emphasis Type="Italic">1H</Emphasis>-1,2,3-triazole ligands: syntheses,structures, optical,and electrochemical properties

Three Cu(II) complexes constructed from 4-(2-pyridyl)-1H-1,2,3-triazole (L), namely, [CuL₂Cl₂]·H₂O, [CuL₂(CH₃OH)(NO₃)]NO₃ and [CuL₂(H₂O)]SO₄, have been synthesized and characterized. X-ray crystal structure analyses revealed that [CuL₂Cl₂]·H₂O and [CuL₂(CH₃OH)(NO₃)]NO₃ have octahedral geometries, whilst [CuL₂(H₂O)]SO₄ adopts a square-pyramidal coordination geometry. In all three complexes, the Cu(II) atoms are chelated by two L ligands in the basal plane, whilst the apical positions are occupied by Cl^?, NO₃^?, CH₃OH or H₂O. The bandgaps between the HOMO and LUMO were estimated by cyclic voltammetry (CV) and diffuse reflectance spectroscopy (DRS) to be 3.43, 3.12, and 3.74 eV, respectively. Theoretical calculations on each structure gave similar results to the experiments. Frontier molecular orbital analyses showed that the higher electron density on the apical ligand, the lower the bandgap.     

Effect of the salting-out agent anion nature on the phase separation of a potassium salt–potassium bis(alkyl polyoxyethylene)phosphate–water systems

The effect the salting-out agent anion nature has on the temperature and concentration intervals of the existence of the separation area is established by analyzing the phase diagrams of pseudoternary KCl (KBr, KI, KNO₃, K₂SO₄, K₄P₂O₇)–potassium bis(alkyl polyoxyethylene)phosphate (oxyphos B)–water systems. It is concluded that the anionic salting-out capability is reduced in the order P₂O₇^4-> SO₄^2-> Cl^? > Br^?> NO₇^4-> SO₃^-> I^?. The thermodynamic parameters of phase separation used to interpret the results are calculated. The observed pattern of a change in the salting-out ability of the investigated salts relative to aqueous solutions of the surfactants is in good agreement with the lyotropic (Hofmeister) series.     

Synthesis,characterization and batch assessment of groundwater fluoride removal capacity of trimetal Mg/Ce/Mn oxide-modified diatomaceous earth

In this study, trimetal Mg/Ce/Mn oxide-modified diatomaceous earth (DE) was synthesized at optimal conditions. Comparison of the SEM images and the results of EDX analyses of the raw and the modified DE confirmed the surface modification of the raw DE with the trimetal oxide. Groundwater fluoride removal capacity of the sorbent was evaluated by batch method at various defluoridation conditions. At a sorbent dosage of 0.6 g/100 mL (contact time: 60 min, mixing speed of 200 rpm and temperature: 297 K), the fluoride removal was >93% for solutions containing initial fluoride concentration of 10–60 mg/L. Sorbent’s optimum fluoride uptake capacity was 12.63 mg/g at the initial fluoride concentration of 100 mg/L. Fluoride removal was >91% for solutions with initial pH range of ∼4–11 (initial fluoride concentration: 9 mg/L, sorbent dosage: 0.6 g/100 mL). Appraisal of the effect of co-existing anions on fluoride removal showed that CO₃²⁻ would reduce the amount of fluoride removed from solution, while other anions such as PO₄³⁻, NO₃⁻ and SO₄²⁻ had no observable effect. K₂SO₄ solution was found to be most suitable for regeneration of spent Mg/Ce/Mn oxide-modified DE compared to Na₂CO₃ and NaOH. The mechanism of fluoride removal at pH > 5.45 (pHpzc = 5.45) occurred by exchange of hydroxyl groups on surface of sorbent with fluoride ions from solution. Sorption data fitted better to Langmuir isotherm and pseudo-second-order model. External diffusion was observed to be the sorption rate limiting factor.     

Coordination‐directed and Hydrogen‐bonded Assembly of Supramolecular Architectures Constructed from Diverse Coordination of Linear,Triangular, Tetragonal Pyramid,Trigonal Bipyramid,and Octahedral Mononuclear Units

Reaction of a imidazole phenol ligand 4‐(imidazlo‐1‐yl)phenol (L) with 3d metal salts afforded four complexes, namely, [Ni(L)₆] · (NO₃)₂ ( 1 ), [Cu(L)₄(H₂O)] · (NO₃)₂ · (H₂O)₅ ( 2 ), [Zn(L)₄(H₂O)] · (NO₃)₂ · (H₂O) ( 3 ), and [Ag₂(L)₄] · SO₄ ( 4 ). All complexes are composed of monomeric units with diverse coordination arrangements and corresponding anions. All the hydroxyl groups of monomeric cations are used as hydrogen‐bond donors to form O–H ··· O hydrogen bonds. However, the coordination habit of different metal ions produces various supramolecular structures. The Ni^II atom shows octahedral arrangement in 1 , featuring a 3D twofold inclined interpenetrated network through O–H ··· O hydrogen bond and π–π stacking interaction. The Cu^II atom of 2 displays square pyramidal environment. The O–H ··· O hydrogen bond from the [Cu(L)₄(H₂O)]²⁺ cation and lattice water molecule as well as π–π stacking produce one‐dimensional open channels. NO₃^– ions and lattice water molecules are located in the channels. 3 is a 3D supramolecular network, in which Zn^II has a trigonal bipyramid arrangement. Two different rings intertwined with each other are observed. The Ag^I in 4 has linear and triangular coordination arrangements. The mononuclear units are assembled into a 1D chain by hydrogen bonding interaction from coordination units and SO₄^2– anions.     

Single-run ion chromatographic separation of inorganic and low-molecular-mass organic anions under isocratic elution: Application to environmental samples

For the isocratic ion chromatography (IC) separation of low-molecular-mass organic acids and inorganic anions three different anion-exchange columns were studied: IonPac AS14 (9 μm particle size), Allsep A-2 (7 μm particle size), and IC SI-50 4E (5 μm particle size). A complete baseline separation for all analyzed anions (i.e., F⁻, acetate, formate, Cl⁻, NO₂⁻, Br⁻, NO₃⁻, HPO₄²⁻ and SO₄²⁻) in one analytical cycle of shorter than 17 min was achieved on the IC SI-50 4E column, using an eluent mixture of 3.2 mM Na₂CO₃ and 1.0 mM NaHCO₃ with a flow rate of 1.0 mL min⁻¹. On the IonPac AS14 column, it was possible to separate acetate from inorganic anions in one run (i.e., less than 9 min), but not formate, under the following conditions: 3.5 mM Na₂CO₃ plus 1.0 mM NaHCO₃ with a flow rate of 1.2 mL min⁻¹. Therefore, it was necessary to adapt a second run with a 2.0 mM Na₂B₄O₇ solution as an eluent under a flow rate of 0.8 mL min⁻¹ for the separation of organic ions, which considerably enlarged the analysis time. For the Allsep A-2 column, using an eluent mixture of 1.2 mM Na₂CO₃ plus 1.5 mM NaHCO₃ with a flow rate of 1.6 mL min⁻¹, it was possible to separate almost all anions in one run within 25 min, except the fluoride-acetate critical pair. A Certified Multianion Standard Solution PRIMUS for IC was used for the validation of the analytical methods. The lowest RSDs (less than 1%) and the best LODs (0.02, 0.2, 0.16, 0.11, 0.06, 0.05, 0.04, 0.14 and 0.09 mg L⁻¹ for F⁻, Ac⁻, For⁻, Cl⁻, NO₂⁻, Br⁻, NO₃⁻, HPO₄²⁻ and SO₄²⁻, respectively) were achieved using the IC SI-50 4E column. This column was applied for the separation of concerned ions in environmental precipitation samples such as snow, hail and rainwater.