Determination of inorganic cations in brine solutions by ion chromatography

The method for analysis of inorganic cations in brine solutions was developed. Ion chromatography is a well-established and accepted technique in the determination of a variety of inorganic ions. However, there are significant complications when ion chromatography is used to determine trace concentrations of inorganic ions in brine matrices. The brine solution in our study was made to simulate the solution from the Waste Isolation Pilot Plant. Instrumental parameters such as eluent composition, flow-rates, and sample loop volumes were investigated to arrive at the optimum condition for the determination of the cations with minimal dilution. Separation was carried out in a Dionex CG12A/CS12A with 8.25 mM H2SO4 as eluent at 1.2 ml/min flow-rate. Our results indicated that ion chromatography is an accurate and a good alternative method for the analysis of cations in brine solution.     

Determination of inorganic ions in drinking water by ion chromatography

Ion chromatography (IC) is now a well established methodology for the analysis of ionic species. The technique is applicable to the determination of a wide range of solutes in many sample types, although the determination of inorganic ions in drinking water continues to be the most widely used application of ion chromatography. Many regulatory and standard organizations, such as ASTM, AOAC, ISO, and US EPA, have approved methods of analysis based upon IC, most of which have been published within the last 10 years. Recent developments in the field of IC, such as the use of higher capacity columns, larger loop injections, more complex sample preparation and detection schemes, have been incorporated into new approved methods to allow the determination of inorganic contaminants, such as bromate, perchlorate, and chromate, at low μg/l levels in drinking waters. IC appears certain to remain an important technique for drinking water analysis and new methods based on IC will continue to be developed as more inorganic contaminants become regulated at lower limits in the future.     

二维离子色谱法同时测定4种无机阴离子和葡萄糖酸根离子

建立了一种新的二维离子色谱分析模式,应用阀切换技术并联抑制电导和脉冲安培双检测体系,同时测定Cl^-、NO₂^-、SO₄^2-、NO₃^-和葡萄糖酸根离子。第一维色谱采用Ionpac AG18+Ionpac AS18阴离子分析柱,分别以5和20 mmol/L的NaOH溶液等度淋洗,流速为1.0 mL/min,进样量为25 μL,抑制电导检测Cl^-、NO₂^-、SO₄^2-和NO₃^-。第二维色谱采用CarboPac PA1+CarboPac PA20两保护柱串联,以90 mmol/L NaOH溶液、0.8 mL/min的流速洗脱,由AG15柱分离富集葡萄糖酸根,脉冲安培检测器检测。结果表明:无机阴离子在0.1~5.0 mg/L、葡萄糖酸根在0.0856~4.2825 mg/L范围内有良好的线性关系,RSD在1.05%~1.94%之间,相关系数(R²)在0.9945以上;无机阴离子的方法检出限为0.615~2.17 μg/L,葡萄糖酸根的方法检出限为24.24 μg/L;回收率在90.3%~102.8%之间。该方法并联两种检测模式,有良好的准确度和精密度,适用于复杂样品的分离分析。     

Determination of inorganic anions in mushrooms by ion chromatography with potentiometric detection

A simple method for determination of common inorganic anions in mushroom samples has been developed by using suppressed ion chromatography with a pH detection unit. The detection unit which was constructed in such a way that practically no additional dispersion occurred consisted of a flow-through quinhydrone pH sensor and a small reference electrode. Chromatographic separation was performed in the order F⁻, Cl⁻, NO₂⁻, Br⁻, PO₄³⁻, ClO₃⁻, NO₃⁻, and SO₄²⁻, at room temperature by using Ion Pac AS 9-HC anion exchange column. Anion extracts from dried mushroom samples at room temperature were homogenized and filtered before injection. Under optimized analytical conditions, the detection limits of the method were between 2 × 10⁻⁶ and 3 × 10⁻⁴ M, depending on the anion studied. The results showed that the concentrations of fluoride and bromide in all mushroom samples were below their limit of detection. Nitrite was found to be the lowest abundant ion, while the most abundant ion was sulfate in all the mushroom samples studied.     

Determination of total dissolved inorganic carbon in freshwaters by reagent-free ion chromatography

Studies of inorganic carbon cycle in natural waters provide important information on the biological productivity and buffer capacity. Determination of total inorganic carbon, alkalinity and dissolved carbon dioxide gives an indication of the balance between photosynthesis and respiration by biota, both within the water column and sediments, and carbon dioxide transfers from the water column to the atmosphere. There are few methods to measure and distinguish the different forms of inorganic carbon, but all require a measure or an indirect quantification of total inorganic carbon. A direct measurement of TIC in water is made possible by the introduction of electrolytic generated hydroxide eluent in ion chromatography which allows to detect a chromatographic peak for carbonate. The advantage of this method is that all the inorganic forms of carbon are converted in carbonate at eluent pH and can be detected as a single peak by conductivity detection. Repeatability of carbonate peak was evaluated at different levels from 0.02 to 6 mequiv.l(-1) both in high purity water and in real samples and ranged from 1 to 9%. The calibration curve was not linear and has to be fitted by a quadratic curve. Limit of detection was estimated to be 0.02 mequiv.l(-1). Accuracy has been estimated by comparing ion chromatography method with total inorganic carbon calculated from alkalinity and pH. The correlation between the two methods was good (R(2)=0.978, n=141). The IC method has been applied to different typologies of surface waters (alpine and subalpine lakes and rivers) characterised by different chemical characteristics (alkalinity from 0.05 to 2 mequiv.l(-1) and pH from 6.7 to 8.5) and low total organic carbon concentrations. This analytical method allowed to describe the distribution of TIC along the water column of two Italian deep lakes.     

离子色谱法测定乙二醇中微量有机酸和无机阴离子

建立了以YSA-8阴离子交换柱的离子色谱法分析乙二醇中微量有机酸和无机阴离子的方法,比较了进样乙二醇浓度对F-及有机酸测定结果的影响,进样乙二醇质量分数低于8.5%时,能够得到较准确的数据.用本法对所测的有机酸和无机阴离子检出限均在8.9 μg/L以下,线性相关系数r在0.996～0.999范围内,标准样中各物质的离子峰面积的相对标准偏差(RSD)在4.2%以下(n＝11),对乙二醇质量分数约为8.5%的样品中F-及有机酸的加标回收率在91.6%～100.0%之间,乙二醇含水料直接测定无机阴离子的加标回收率在91.8%～104.8%之间.     

Determination of trace inorganic anions in anionic surfactants by single-pump column-switching ion chromatography

An ion chromatography method has been proposed for the determination of three common inorganic anions(chloride,nitrate and sulfate) in anionic surfactants using a single pump system.The new system consists of an ion exclusion column,a concentrator column,and an anion exchange column connected in series via two 6-ports valves in a Dionex ICS-2000 ion chromatograph.The valves were switched several times for removing surfactants,concentrating and separating the three anions.The chromatographic conditions were optimized.Detection limits(S/N = 3) were in the range of 0.10-0.68μg/L.The relative standard deviations(RSDs) of peak area were less than 4.6%.The recoveries were in the range of 84.1-112.6%.     

Determination of atmospheric concentrations of inorganic anions by ion chromatography following ultrasonic extraction

The capability of the suppressed conductometric detection ion chromatography (IC) was investigated for the separation and determination of inorganic anions (F-, Cl-, NO3- and SO4(2-)) in standard reference materials SRM-1648 urban particulate matter following ultrasonic extraction. The effects of the cationic surfactant (SDS) and the anionic surfactant (CTAB) on ultrasonic extraction efficiency of inorganic anions from complex matrix of airborne particulate matter were investigated. The results showed that surfactant can enhance the extraction efficiency. Finally, the concentrations of inorganic anions in the atmosphere of the city of Isfahan were determined. The results showed a trend of SO4(2-) > NO3- > Cl- > F-.     

Determination of trace inorganic anions in seawater samples by ion chromatography using silica columns modified with cetyltrimethylammonium ion

Conventional silica columns dynamically modified with cetyltrimethylammonium ions were evaluated for the determination of UV-absorbing bromide, nitrate, and nitrite in seawater samples. Cetyltrimethylammonium, which is a quaternary ammonium ion, was dynamically introduced onto silica surfaces. The first layer of the modifier was introduced by electrostatic interaction, whereas the second layer was introduced by hydrophobic interaction. The latter layer worked as the anion-exchange sites. The modified conventional silica columns could be used for separation of inorganic anions. Separation of authentic mixture of five anions was achieved within 17 min. The addition of 0.1 mM cetyltrimethylammonium ion to the eluent improved the repeatability of the retention time. Seawater samples could be directly injected onto the prepared conventional silica columns, and bromide, nitrate, and nitrite levels were determined to be 69, 0.13, and 0.016 ppm, respectively.     

Separation of inorganic anions by unsuppresed ion chromatography

The elution behaviour of 11 inorganic anions is investigated by unsuppressed ion chromatography with PRP-X100 a macroporous poly(styrene-divinylbenzene) strong-base anion-exchanger. Weak acids (cyanide and sulfide) can be separated and detected at pH 9 with sodium p-hydroxybenzoate as the eluent.     

Determination of common inorganic anions and cations by non-suppressed ion chromatography with column switching

An ion chromatography (IC) method has been proposed for the determination of seven common inorganic anions (F(-), H(2)PO(4)(-), NO(2)(-), Cl(-), Br(-), NO(3)(-), and SO(4)(2-)) and/or five common inorganic cations (Na(+), NH(4)(+), K(+), Mg(2+), and Ca(2+)) using a single pump, a single eluent and a single detector. The present system used cation-exchange and anion-exchange columns connected in series via a single 10-port switching valve. The 10-port valve was switched for the separation of either cations or anions in a single chromatographic run. When 1.0mM trimellitic acid (pH 2.94) was used as the eluent, the seven anions and the five cations could be separated on the anion-exchange column and the cation-exchange column, respectively. The elution order was found to be F(-)相似文献   

离子色谱法测定醇胺脱硫溶液中热稳定盐

为了控制热稳定盐(HSS)对天然气净化装置造成的危害,建立了一种同时检测醇胺脱硫溶液中的乙酸根离子、甲酸根离子、氯离子、硫酸根离子、草酸根离子、硫代硫酸根离子和硫氰酸根离子的离子色谱方法。该方法利用膜过滤、反相固相萃取和稀释3个步骤对工业样品进行前处理,采用氢氧化钾梯度淋洗和电导检测的方式,实现了7种离子的分离与检测。方法的线性范围为0.01～0.5 mmol/L,检出限(以信噪比(S/N)为3计)小于0.1 mg/L,回收率为80.0%～100.3%。在5个不同添加浓度下分别测定了上述7个离子,色谱峰面积的重复性良好(相对标准偏差(RSD, n=10)为0.94%～3.99%。通过3个实验室比对试验,表明该方法再现性良好,色谱峰面积的RSD小于5%。应用该方法成功地检测了8家天然气净化厂、3家石油炼厂和1家煤制油工厂的脱硫溶液样品中的HSS,并连续监测某天然气净化装置15 d。该方法具有良好的可靠性和实用性。     

Determination of inorganic and organic anions in one run by ion chromatography with column switching

A method for the simultaneous determination of low-molecular-mass organic and inorganic anions in aqueous solutions was developed using isocratic ion chromatography (IC) with suppressed conductimetric detection and column switching. Owing to the large differences in distribution coefficients between sulphate, nitrate and phosphate and the other species, these ions are separated in the first stage on a medium-capacity anion exchanger, whereas the other anions are led through a second column packed with a high-capacity anion-exchange resin via a column-switching valve. After optimization of the switching procedure a spiked drinking water sample was analysed. Fluoride, acetate, butyrate, formate, nitrate, nitrite and phosphate could be determined in addition to the main anions (chloride and sulphate). The time for a complete analysis is less than 20 min and the method can easily be automated. The precision and detection limit are as usual in IC with background suppression.     

Determination of inorganic anions in natural water by microcolumn ion chromatography with on-column enrichment.

An on-column enrichment method was developed for the rapid determination of inorganic anions in natural water. The system was assembled from a syringe pump, a six-port switching valve with a sample-enrichment loop, a separation column and a UV detector. The enrichment efficiency of the system was tested by using inorganic anions as samples. The limits of detection were between 0.6 and 7.7 microg/L. The system was applied to the determination of anions in river and pond-water samples.     

Determination of inorganic anions in ethyl acetate by ion chromatography with an electromembrane extraction method

In this work, the determination of inorganic anions in slightly water-soluble organic solvents (ethyl acetate) was realized by ion chromatography (IC) with a novel-efficient electromembrane extraction method. From an 8 mL ethyl acetate sample, three inorganic anions migrated through the pores of a polypropylene hollow fiber membrane, and into deionized water inside the lumen of the hollow fiber by the application of 600 V. The transport was forced by an electrical potential difference sustained over the liquid membrane, resulting in electrokinetic migration of inorganic anions from the donor compartment to the acceptor solution. After the electromembrane extraction, the acceptor solution was analyzed by IC with a sodium carbonate-sodium bicarbonate eluent. The applied voltage, stirring speed, and extraction time for controlling the extraction efficiency were optimized. Within 10 min of operation at 600 V, chloride, bromide, and sulfate were extracted with recoveries in the range 76-110%, which corresponded to a linear range of 0.01-1 mg/L. The procedure was applied to the analysis of inorganic anions in a real ethyl acetate sample and expands onto other slightly water-soluble organic solvents.     

Advances in the determination of inorganic anions by ion chromatography

The time period covered for this review includes articles published from 1997 to 1999, with the addition of a few classic references. The purpose of the review is to include the most relevant works from each topic area of the determination of inorganic anions by ion chromatography, including new sample pretreatments, new separation methods, new detection systems and the latest applications in the field of environmental, water, foods, etc. samples. Experimental conditions such as stationary phase, eluent, detection mode, as well as matrix are summarized in a table.     

Determination of glyphosate by ion chromatography

An ion chromatography system for the determination of glyphosate was described. Ion chromatograph was carried out by suppressed conductivity detection (DX-100). The eluent contained 9 mmol l⁻¹ Na₂CO₃ and 4 mmol l⁻¹ NaOH. The detection limit was 0.042 μg ml⁻¹ (S/N=3). The relative standard deviation was 1.99% and the correlation coefficient of the calibration curve for area was 0.9995. The linear range was 0.042100 μg ml⁻¹. Common inorganic ion and organic acids did not interfere. The recovery was 96.4103.2%. The method was simple, rapid, reliable and inexpensive.     

Determination of monovalent inorganic anions in high-ionic-strength samples by electrostatic ion chromatography with suppressed conductometric detection

A new ion chromatographic (IC) system has been established by using micelles of 3-(N,N-dimethylmyristylammonio)propanesulfonate (Zwittergent 3-14) loaded onto a reversed-phase packed column as the separation column with an electronic rotary switching valve packed-bed suppressor for conductometric detection of inorganic anions. An aqueous H3BO3-Na2B4O7 solution has been demonstrated to be the most desirable eluent for this IC system. The relationship between retention time and the concentration of the borate eluent was determined for a series of model anionic analytes and this relationship was found to be opposite to that exhibited in a conventional anion-exchange IC system. The rapid elution and complete separation of monovalent inorganic anions were obtained by initially using a high-concentration borate solution as the eluent for a short-period, and then switching to a lower-concentration borate eluent to complete the separation. Detection limits for nitrite, bromide, nitrate, and chlorate were 0.85, 0.88, 0.95 and 4.8 microM, respectively, when a 7.0 mM Na2B4O7 eluent was used. Moreover, the ability to directly detect these monovalent anions in samples containing high concentrations of sulfate and/or chloride ions provided a major advantage of this approach.     

Determination of inorganic anions in ethyl acetate by in-line hollow fiber membrane extraction with ion chromatography

In this work,a novel hollow fiber membrane extractor was set up to extract inorganic anions from ethyl acetate using deionized water.Inorganic anions in slightly soluble organic solvents can be determined by the in-line hollow fiber membrane extractor coupled with ion chromatography at first time.Different aspects of the extraction procedure such as magnetic stirring speed, extraction flow rate and extraction time were optimized to achieve high extraction efficiency and good separation results. Satisfact...     

Determination of organic acids in the presence of inorganic anions by ion chromatography with suppressed conductivity detection

Simultaneous separation of 19 organic acids and 10 inorganic anions has been demonstrated using ion chromatography with a high capacity anion exchange column and the suppressed conductivity detector under an auto-suppression external sulfuric acid mode. Quantitative merits of this method were examined for analysis of nine organic acids of potential significance in cell culture broth. External calibration curves for these analytes were linear with correlation coefficients exceeding 0.999, and the relative standard derivations of observed analyte concentrations were less than 3.0% in both inter- and intra-day evaluations of aqueous standards. Developed methodology was subsequently applied to obtain organic acid profiles of Luria-Bertani liquid media, yeast extract, peptone, and the culture broth of a mutant Escherichia coli strain. Analytes recoveries observed for triplicate analysis of LB media spiked at two concentration levels ranged from 88% to 105% with less than 7% RSD. These data demonstrate quantitative accuracy for LB media and suggest that the report method may also be applicable to complex samples such as fermentation mixture and lignocellulose hydrolysate.