Suppressed electrostatic ion chromatography with tetraborate as eluent and its application to the determination of inorganic anions in snow and rainwater

Tetraborate is investigated as the eluent ion for suppressed electrostatic ion chromatography (EIC) using a zwitterionic stationary phase. Good separation of a range of inorganic anions (SO4(2-), Cl-, NO3-, Br-, NO3-, ClO3-, and I-) was obtained, with detection limits for highly conducting ions (SO4(2-), Cl-, NO2-, Br- , and NO3-) being less than 8 x 10(-8) M, and for weakly conducting anions (ClO3- and I-) being 2.7 x 10(-7) and 5.8 x 10(-7) M, respectively. Calibration curves were linear up to 1.8 mM of each analyte. Retention times were found to increase with increasing eluent concentration and a linear relationship was observed between log k' and log[Na2B4O7] for all analytes. This behaviour is attributed to the progressive formation of a binary electrical double layer at the surface of the zwitterionic stationary phase. Retention times of analytes could be manipulated by varying the concentration of the eluent. This new suppressed-EIC system was applied to the determination of inorganic anions (SO4(-2) , CI-, NO3-, NO2-, and Br-) in snow and rainwater samples.     

离子色谱法测定火场爆炸残留物中7种阴离子

建立了离子色谱法测定爆炸残留物中F,Cl,NO_2,SO_4,Br,NO_3,PO_47种阴离子的方法。采用抑制电导检测器,以DIONEX Ion Pac~?AS11–HC型阴离子交换柱为分离柱,柱箱温度为40℃,以22 mmol/L KOH溶液为淋洗液,流量为1.20 m L/min。F~–,Cl~–,NO_2~–,SO_4~(2–),Br~–,NO_3~–,PO_4~(3–)在各自范围内均呈良好的线性关系,相关系数均大于0.999,检出限在0.06~0.15 mg/L之间,加标回收率为92.5%~101.3%,测定结果的相对标准偏差为1.86%~2.79%(n=7)。该方法简便、快捷,选择性好,灵敏度高,可满足分析要求。     

离子色谱法测定茶叶中无机阴离子及其用于茶叶的分类

提出了离子色谱法测定茶叶中F-、Cl-、NO2-、Br-、NO3-、H2PO4-、SO42-等无机阴离子的方法。采用Shodex IC SI-52 4E阴离子分离柱进行分离,以3.6mmol.L-1碳酸钠溶液和甲醇以体积比98比2混合所得溶液为淋洗液进行洗脱,从而实现7种阴离子的分离。根据茶叶中分离出的7种阴离子含量的不同,利用聚类分析将16个茶叶样品进行分类。     

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, HPO42-, SO42-, 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 x 10(-4) mM and linear calibration plots up to 7.0 mM were obtained with a suppressed conductivity system.     

Successive non-suppressed ion chromatography of common cations and anions using dual columns with single eluent

A successive non-suppressed ion chromatography (IC) system for the determination of common cations (Na+, K+, Mg2+, Ca2+) and anions (Cl-, Br-, NO3-, SO4(2-)) was developed, using two separation columns and a single eluent. 5-Sulfoisophthalic acid eluent was very suitable for such separations with a commercially available cation-exchange column for the mono- and di-valent cations and with an ODS column coated with cetyltrimethylammonium for the anions. Both cations and anions were detected with conductimetrically high sensitivity without any suppressor. After injecting an aliquot of sample solution, the solvent front from the cation-exchange column, including most of the anionic species, was firstly accumulated into the additional 2 ml accumulation loop for 60 s, while the cation IC was performed. Subsequently, the accumulated fraction was introduced into the anion-exchange column and chromatographed. Relative standard deviations (RSDs) of retention times and conductimetric area responses for common cations were within 6% and within 4%, respectively. The linear relationships between molar concentration and detector response ranged from 0.01 to 1.00 mM with r2 of 0.9994 for Na+, 0.9992 for K+, 0.9993 for Mg2+, and 0.9988 for Ca2+. The successive anion IC through the accumulating process was also quantitative, with 95% recovery or over for each analyte. The linear ranges were between 0.01 and 1.00 mM with r2 of 0.9996 for Cl-, 0.9997 for Br-, 0.9993 for NO3-, and 0.9984 for SO4(2-). The method was applied to the determination of common cations and anions in several mineral waters and a hot spring water.     

不纯流动相对离子法分析无机阴离子的影响(英文)

 采用离子模拟研究了流动相不纯对样品中无机阴离子测定造成的干扰。结果表明 ,在流动相中加入Cl-,使得其他 6种阴离子响应值增加。这主要是由于Cl-加入的同时也带来了相应的阳离子 ,在通过抑制器时可带来等量的H+ ,H+ 伴随着各个阴离子样品一起通过检测器 ,使总的样品离子响应值增加。在 6种阴离子中 ,F-和NO-2 对AS14柱的亲和力和Cl-相近 ,其响应值随Cl-加入量的变化趋势相似 ;Br-,NO-3 ,PO3 -4及SO2 -4因其对柱的亲和力大于Cl-,它们的响应值随Cl-加入量的变化趋势也相同。     

Simultaneous ion chromatographic separation of anions and cations on poly(aspartic acid) functionalized silica

Poly(aspartic acid)-silica (PolyCAT A), originally designed for the cation-exchange chromatography of proteins, is proposed for the simultaneous ion chromatographic separation of inorganic anions and cations. This is possible owing to the zwitterion-exchange properties of this stationary phase, which are attributed to the presence of both protonated aminopropyl and dissociated carboxylic groups in poly(aspartic acid) attached to the silica. The retention of alkali metal (Li+, Na+, K+), alkaline earth metal (Mg2+, Ca2+), ammonium and inorganic anions (Cl-, H2PO4-, Br-, NO2-, I-, IO3-, NO3-, ClO4-, SCN-) was tested in aqueous solutions of sulfuric, perchloric, sulfosalicylic, citric, oxalic, maleic and aspartic acids with conductimetric detection. The effect of eluent pH, together with the concentration and characteristics of the eluting ions, were studied. Under optimum conditions (0.3 mmol dm(-3) H2SO4-0.2 mmol dm(-3) Li2SO4 eluent), the simultaneous separation of three anions (Cl-, H2PO4-, NO3-) and four cations (Na+, K+, Mg2+, Ca2+), on a PolyCAT A column (200 x 4.6 mm id, 5 microm film thickness) was achieved in 9 min.     

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-.     

Separation and simultaneous determination of four artificial sweeteners in food and beverages by ion chromatography

In this paper, the separation and determination of four artificial sweeteners (aspartame, sodium cyclamate, acesulfame-K and sodium saccharin) by ion chromatography coupled with suppressed conductivity detector is reported. The four artificial sweeteners were separated using KOH eluent generator. Due to the use of eluent generator, very low conductance background conductivity can be obtained and sensitivity of sweeteners has been greatly improved. Under the experimental condition, several inorganic anions, such as F-, Cl-, NO3-, NO2-, Br-, SO4(2)-, PO4(3)- and some organic acid such as formate, acetate, benzoate, and citrate did not interfere with the determination. With this method, good linear relationship, sensitivity and reproducibility were obtained. Detection limits of aspartame, sodium cyclamate, acesulfame-K, sodium saccharin were 0.87, 0.032, 0.019, 0.045 mg/L, respectively. Rate of recovery were between 98.23 and 105.42%, 99.48 and 103.57%, 97.96 and 103.23%, 98.46 and 102.40%, respectively. The method has successfully applied to the determination of the four sweeteners in drinks and preserved fruits.     

茶叶中无机阴离子的毛细管电泳分离间接检测方法的研究

建立了毛细管电泳分离测定茶叶中Cl-、NO2-、NO3-、SO42-、F-及HPO24-的方法。通过研究分离电压、背景电解质和电渗流改性剂的浓度、pH的影响优化了分析条件。在优化条件下,6种无机阴离子在10min内得到完全分离,各组分迁移时间和峰高的相对标准偏差(RSD)分别为1.9%~4.7%和1.2%~3.8%,检出限为0.11~0.82 mg/L。通过分析实际样品并做加标回收实验验证了该方法的可行性,Cl-、NO3-、SO42-及HPO24-的回收率为93%~98%。     

整体柱离子相互作用色谱快速分析无机阴离子

研究了用硅胶整体柱和直接电导检测的离子相互作用色谱快速分析常见无机阴离子的方法。实验采用氢氧化四丁铵和邻苯二甲酸为淋洗液,讨论了包括淋洗液浓度、流速和pH对分离的影响。当以1.5 mmol/L氢氧化四丁铵和1.1 mmol/L邻苯二甲酸为淋洗液(pH 5.5),流速6 mL/min时,可以在1 min内分离Cl-、NO2-、Br-、NO3-、ClO3-、SO42-和I-7种阴离子。方法的检出限为0.3~1.9 mg/L,峰面积、峰高的相对标准偏差(RSD,n=5)分别为0.4%~2.2%和0.1%~1.5%。将该法用于测定矿泉水和地下水中的阴离子,加标回收率在97.9%~100.3%之间。     

离子色谱法测定农村饮用水中阴离子

采用离子色谱法测定农村饮用水中F-、Cl-、NO2-、Br-、NO3-和SO42-等6种阴离子的含量。水样经Ion Pac AG19保护柱及Ion Pac AS19分离柱分离,以20.00mmol·L-1氢氧化钾溶液为淋洗液,采用抑制电导器检测。F-、NO2-和Br-在4mg·L-1以内,Cl-、NO3-和SO42-在40mg·L-1以内呈线性关系,检出限(2S/N)在0.002～0.012mg·L-1之间。方法用于水样中6种阴离子的测定,加标回收率在98.0%～101.3%之间,相对标准偏差(n=6)在0.83%～2.7%之间。     

Determination of inorganic anions in biological fluids with direct sample injection by electrostatic ion chromatography using zwitterionic micelles in both stationary and mobile phases

A new ion chromatographic (IC) system, which uses zwitterionic (e.g., Zwittergent 3-14) micelles as both stationary and mobile phases, highly useful for the analysis of inorganic anions in biological samples, was developed. The zwitterionic micellar stationary phase (which is obtained by immobilizing the zwitterionic surfactant on surfaces of the reversed-phase ODS) showed high ability to confine the elution bands of the large amount of SO4(2-) and Cl- to narrow zones. As a result, a base-line separation of NO2-, Br- and NO3- from SO4(2-) and Cl- is always achieved. The zwitterionic micellar mobile phase, (which is obtained by dissolving the zwitterionic surfactant with a suppressive electrolytic solution, e.g., aqueous NaHCO3 solution), on the other hand, showed high ability for rapid elution of proteins. The separation column is therefore always being cleaned up even after the protein-containing sample is directly injected. The zwitterionic micelles are also insensitive to conductivity detection, therefore either the suppressed or the non-suppressed conductivity detection method is applicable for detection of the analyte ions. Urine and serum were chosen as the model real samples and were analysed with direct sample injection; the results of successful determination of a number of inorganic anions (SO4(2-), Cl-, NO2-, Br- and NO3-) in both samples have demonstrated the usefulness of this new IC system.     

微波浓缩/离子色谱法测定印刷电路板表面的7种痕量无机阴离子

建立了印刷电路板上7种痕量无机阴离子(F-、NO-2、Cl-、Br-、NO-3、PO3-4、SO2-4)的微波浓缩/离子色谱测定方法.印刷电路板样品经纯水提取,微波浓缩后,在Ionpac AS23分析柱上,以4.5 mmol/LNa2 CO3+0.8 mmol/L NaHCO3为淋洗液,流速为1.0 mL/min.结果...     

碱化底液消除水负峰离子色谱法测定水中F~–,Cl~–等7种阴离子

在研究消除水负峰的基础上,建立离子色谱法测定水中F–,Cl–,NO2–,H2PO4–,Br–,NO3–,SO42–7种阴离子的方法。经实验确定淋洗液为4.5 mmol/L NaHCO3–4.0 mmol/L Na2CO3,淋洗液流量为1.0 mL/min,柱箱温度为35℃。在底液中加入与淋洗液同浓度的Na2CO3–NaHCO3可有效消除水负峰。该方法对7种阴离子的检出限为0.004~0.034 mg/L,测定结果的相对标准偏差为0.69%~3.57%(n=6),加标回收率为95%~105%。该法能有效消除水负峰及其对F–测定的影响,操作简便、测定结果准确可靠,适用于水中F–、Cl–等7种阴离子的测定。     

Aggregation behavior of hexadecyltrimethylammonium surfactants with various counterions in aqueous solution

Both thermodynamic and microenvironmental properties of the micelles for a series of cationic surfactants hexadecyltrimethylammonium (C16TAX) with different counterions, F-, Cl-, Br-, NO3-, and (1/2)SO4(2-), have been studied. Critical micelle concentration (CMC), degree of micelle ionization (alpha), and enthalpy of micellization (DeltaH(mic)) have been obtained by conductivity measurements and isothermal titration microcalorimetry. Both the CMC and the alpha increase in the order SO4(2-) < NO3- < Br- < Cl- < F-, consistent with a decrease in binding of counterion, except for the divalent anion sulfate. DeltaH(mic) becomes less negative through the sequence NO3- < Br- < Cl- < F- < SO4(2-), and even becomes positive for the divalent sulfate. The special behavior of sulfate is associated with both its divalency and its degree of dehydration. Gibbs free energies of micellization (DeltaG(mic)) and entropies of micellization (DeltaS(mic)) have been calculated from the values of DeltaH(mic), CMC, and alpha and can be rationalized in terms of the Hofmeister series. The variations in DeltaH(mic) and DeltaS(mic) have been compared with those for the corresponding series of gemini surfactants. Electron spin resonance has been used to assess the micropolarity and the microviscosity of the micelles. The results show that the microenvironment of the spin probe in the C16TAX surfactant micelles depends strongly on the binding of the counterion.     

Method development and validation for the determination of various sulfur-containing anions and other anions in the corrosion process by capillary ion electrophoresis with indirect detection

A method of capillary ion electrophoresis with indirect detection is developed for the simultaneous determination of the sulfur-containing anions S2O4(2-), S2O3(2-), SO4(2-), SO3(2-), and S2- and other anions (Cl-, Br-, NO2-, NO3-, (COO)2(2-), F-, and PO4(3-)) in the corrosion process. The effects of pH, tetradecyltrimethylammonium hydroxide, chromate, 2-[n-cyclohexylamino]-ethane sulfonate, calcium gluconate, and acetonitrile on the migration and resolution of the anions and the stability of sulfur-containing anions are systematically investigated. The detection limits, repeatability, and linearity for the anions are comparatively studied at 374, 274, and 254 nm, and the results show that 374 nm is the optimal length. The simultaneous multiwavelength detection at 374, 254, 214, and 195 nm can assist in confirming the identification of UV-absorbing anions.     

对二甲氨基苯甲酸的阴离子识别应用研究

采用紫外分光光度法和荧光分光光度法研究了主体分子对二甲氨基苯甲酸与HPO42-、SO42-、H2PO4-、ClO4-、HSO4-、NO3-、BF4-、PF6-、F-、Cl-和Br-等11种阴离子客体的识别作用.发现在乙腈溶液中,该主体分子对二价阴离子HPO42-和SO42-表现了强亲和力和高选择性;并对一价阴离子F-和H2PO4- 具有一定的响应能力;而与一价阴离子ClO4-、HSO4-、NO3-、BF4-、PF6-、Cl-和Br-几乎没有作用.结果表明主客体分子本身的酸碱性和阴离子的负电荷数目是影响主体分子对阴离子识别性能的主要因素.     

A selective detection of fluoride ions in DMSO by fluorescent and colorimetry competition assays based on 4-bromo-2,6-bis-(hydroxymethyl)phenol

A novel and very simple colorimetric and fluorometric method for selectively sensing F^- was proposed based on 4-bromo-2,6- bis（hydroxymethyl）phenol（BBHMP）,which is a simple and available phenolic receptor the absence of any special chromophoric function and with over wide range of anions（Cl^-,Br^-,I^-,AcO^-,HSO₄^-,NO₃^- and BzO^-） in DMSO media.The colorimetric method is described for naked-eye detection of F^- in the presence of the BBHMP.The BBHMP was found to show selective and sensitive fluorescence quenching response toward fluoride over than Cl^-,Br^-,I^-,AcO^-,HSO₄^-,NO₃^- and BzO^-.     

Use of zwitterionic micelles in the eluent: a new approach for ion chromatographic (IC) analysis of ions in biological fluids with direct sample injection

The problem of column performance degradation due to irreversible binding of proteins encountered in ion chromatographic (IC) analysis of ions in protein-containing samples was overcome by using zwitterionic micelles (e.g., Zwittergent-3-14) as a portion of the eluent. A zwitterionic micellar eluent showed high ability for solubilization of proteins, and, hence, the protein-containing samples could be analyzed without need for deproteinization. On the other hand, the zwitterionic micelle was insensitive to conductivity but interacted with the analyte ions, due mainly to its unique configuration of charges (namely, the zwitterionic micelle containing both positively and negatively charged groups but carrying no net charge). Using a zwitterionic micellar eluent, the analyte ions could be detected selectively and sensitively, and moreover, the selectivity for the analyte ions was unique. A conventional anion-exchange column conditioned with a Zwittergent-3-14 micellar eluent was applied for the analysis of real biological samples (serum and urine) with direct sample injection. The results of the successful detection of inorganic anions (Cl-, SO4(2-), NO2-, Br-, and NO3-) have demonstrated the usefulness of this new IC approach for the analysis of biological samples.