煤燃烧脱硫过程中含硫阴离子的离子色谱分析

建立了煤燃烧脱硫过程中主要含硫阴离子及常见无机阴离子的快速离子交换色谱分离和定量方法。以 0 .8mmol/L邻苯二甲酸氢钾作流动相 ,非抑制型电导检测法检测SO32 - 和SO42 - 的下限浓度分别为 0 .5mg/L和 1 .0mg/L。所建立的分析方法被用于脱硫方法的研究。同时 ,验证了甲醛溶液作为SO32 - 保护剂的机理是甲醛与SO32 - 形成了稳定的配合物。     

Derivatization of amines with chloroformate esters for gas chromatographic analysis

Summary The gas chromatographic analysis of amines after conversion to electron capture sensitive carbamates in two-phase systems has been studied. Hydrophilic compounds, for instance methylamine, are reacted with 2,2,2-trichloro-tert. butyl chloroformate. Quantitation below 10^–7 M can be made by thermionic or electron capture detection. A hydrophobic amine, namely N,N-dimethyl-n-octylamine, was derivatized with 2,4,6-tribromophenyl chloroformate with addition of iodide ion to the aqueous phase. The favorable effect of iodide ion as well as the choice of pH and chloroformate ester is discussed.Presented at the 14th International Symposium on Chromatography London, September, 1982     

Ion chromatographic determination of some anions and alkaline cations in liquid crystal materials after ultraviolet irradiation

A method was developed for the quantitative determination of inorganic cations and anions present in liquid crystal materials pretreated with ultraviolet irradiation by ion chromatography. The samples were irradiated at less than 20±2 °C and then pretreated with OnGuard RP and P cartridges to remove the interferential organic compounds prior to ion chromatographic analysis for both cations and anions. With a high capacity and very hydrophilic anion exchange column, four anions (fluoride, chloride, bromide, iodide) were determined in 20 min with gradient of sodium hydroxide. By employing a cation exchange column, five cations (sodium, ammonium, potassium, magnesium, calcium) could be determined in 12 min. The spiked recoveries for the cations and anions were 84.0–108.1% and 86.1–108.2%, respectively.     

Ion chromatographic behaviour and determination of perbromates

Ion chromatographic behaviour of perbromates in aqueous solutions was studied, using ion suppressed conductimetric detection (Dionex DX-100 ion chromatograph with ASRS-I suppressor). Various eluents (sodium hydroxide, carbonate and phenate solutions) were examined using the AS-14  mm anion-exchange column and an optimization study concerning pH and total eluate concentration of mobile phase was carried out. Phenate buffer (20.0 mM, pH 11.0) at 1.18 ml/min flow rate, gave the best results. Calibration curve was linear in the range of 1.5-200 ppm, with a limit of detection of 0.46 ppm and R.S.D. 1.8% (100 ppm standard). Perbromates were separated with good resolution from potentially interfering anions (bromides, bromates, iodides, perchlorates). Selectivity coefficients were determined for perbromates, perchlorates and iodides, from linear plots of retention volume versus the reciprocal of eluent concentration. The new method was used to monitor the perbromate reactions with lactic acid, iodide and citric acid in the absence and presence of Fe(II) acting as an inducer. Furthermore, it was confirmed the inability of various common strong oxidative media to oxidize bromate to perbromate.     

Ion chromatographic determination of chloride,chlorate, and perchlorate in sulfuric acid solutions

Summary The determination of chloride and perchlorate by non-suppressed ion chromatography in aqueous process solutions containing a high sulfate background is described. The method is reliable and fast. The sensitivity for perchlorate is lower than for other anions like nitrate, nitrite and chlorate. The detection limits are about 0.3 g/ml with linear calibration curves within a concentration range from 1 to 50 g/ml.     

离子色谱测定农用硫酸铵中4种杂质阴离子

建立了离子色谱法同时测定农用硫酸铵中氟、氯、溴、硫氰酸盐的分析方法。样品经水提取,Ba离子柱净化后,离子色谱法测定。4种阴离子浓度在各自线性范围内与相应峰面积呈线性关系,相关系数r＞0.999,加标回收率为80.23%～111.50%,精密度（RSD）为0.62%~9.08%。称样量为0.1g时,氟、氯的方法检出限为10mg/kg;溴、硫氰酸盐方法检出限为20mg/kg。该方法样品前处理简单、快捷,重复性及回收率均能达到检测分析要求,可以应用于农用硫酸铵中杂质阴离子的检测。     

Ion chromatographic separation of alkylsulphonic acids with conductivity detection

Summary An ion chromatographic (IC) method has been developed for the separation of alkylsulphonic acid. Two different stationary phases, silica-based and polymer-based ion-exchange resins, were studied using pure ion exchange and/or hydrophobic interaction mechanisms. Correlations between analyte hydrophobicity and eluent polarity were made in order to investigate the possibility of changing the dominant separation mechanism by varying the eluent composition. The alkyl chain lengths of the sulphonic acids analysed ranged from C₁ to C₉. Detection limits in the submicromolar range were obtained by suppressed conductivity detection.     

Electro membrane extraction of biological anions with ion chromatographic analysis

A simple and sensitive single step electro membrane extraction (EME) procedure was demonstrated for biological organic anions with determination by ion chromatography (IC). Nitrite, adipate, oxalate, iodide, fumarate, thiocyanate and perchlorate were extracted from aqueous donor solutions, across a supported liquid membrane (SLM) consisting of methanol impregnated in the walls of a porous polypropylene membrane bag and into an alkaline aqueous acceptor solution in the lumen of the propylene envelope by the application of potential of 12 V applied across the SLM. The acceptor solution was analyzed by IC. Parameters affecting the extraction performance such as type of SLM, extraction time, pH of the donor and acceptor solution, and extraction voltage were studied. The most favorable EME conditions were methanol as the SLM, extraction time of 5 min, pH of acceptor and sample solutions of 12 and 4, respectively, and a voltage of 12 V. Portable 12 V batteries were used in the study. Under these optimized conditions, all anions had enrichment factors ranging from 3.6 to 36.2 with relative standard deviations (n = 3) of between 6.6 and 17.5%. Good linearity ranging from 0.1 to 10 μg mL⁻¹ with coefficients of correlation (r) of between 0.9981 and 0.9996 were obtained. The limits of detection of the EME-IC method were from 0.01 to 0.14 μg mL⁻¹. The developed methodology was applied to amniotic fluid samples to evaluate the feasibility of the method for real applications.     

Ion chromatographic separation of alkylsulphonic acids with conductivity detection

Summary An ion chromatographic (IC) method has been developed for the separation of alkylsulphonic acid. Two different stationary phases, silica-based and polymer-based ion-exchange resins, were studied using pure ion exchange and/or hydrophobic interaction mechanisms. Correlations between analyte hydrophobicity and eluent polarity were made in order to investigate the possibility of changing the dominant separation mechanism by varying the eluent composition. The alkyl chain lengths of the sulphonic acids analysed ranged from C₁ to C₉. Detection limits in the submicromolar range were obtained by suppressed conductivity detection.     

A computer program for the optimal ion chromatographic determination of anions in waters

Summary A general form of computer program which can assist in method development for any natural water has been developed. Necessary input data, sequence of main operations, necessary mathematical relationships and the output data are specified. The development of the structure of the computer program was based on experiences with real samples.     

Ion chromatographic determination of some organic acids, chloride and phosphate in coffee and tea

An ion chromatographic method for the simultaneous determination of organic acids and inorganic ions is described. Acetic, malic, ascorbic, citric, malic and succinic acids, chloride and phosphate were determined in coffee and tea samples. The separation is performed on an anion-exchange column operated at 40 °C within 25 min by an isocratic elution with 0.6 mM aqueous potassium hydrogenphthalate (pH 4.0) solution containing 4% (v/v) acetonitrile as eluent and determination by conductivity detection. The method does not need a special sample treatment and was successfully applied to the analysis of black, green and oolong tea samples. Also, green and roasted coffee samples from the varieties arabica and robusta were analyzed.     

High-speed analysis for acid-rain anions by Single-Column Ion Chromatography (SCIC)

Summary Single Column Ion Chromatography (SCIC) combines ion exchange separation with direct electrical conductivity detection. Because no supressor column is used in SCIC the post-column dead volume is minimized. This means that HPLC technology can be applied to reduce analysis times. The analysis of chloride, nitrate, and sulphate can be accomplished in 6 min using a standard 250×4.6 mm LC column packed with a low-capacity ion-exchange chemically bonded silica leading to a sensitivity of 100 ppb. A 1 min analysis for chloride, nitrate, and sulphate at the ppm level is possible using a 30×4.6 mm column eluted with 4mM phthalate buffer at pH 4.5.Presented at the 14th International Symposium on Chromatography London, September, 1982     

Determination of aliphatic amines by cation‐exchange chromatography with suppressed conductivity detection after solid phase extraction*

A sensitive method for the determination of underivatized aliphatic amines based on cation exchange chromatography coupled with suppressed conductivity detection scheme and solid phase extraction (SPE) procedure has been developed. A surface modified styrene divinylbenzene polymeric sorbent, based on a reversed‐phase (RP) and strong cation exchange (SCX) mixed mode was used as an active material for the SPE of amines. The conductometric capabilities of several aliphatic mono‐ and polyamines, expressed in terms of molar sensitivity (nS/μM), were determined. The LODs, obtained without the SPE treatment, ranged between 20 and 65 nM for putrescine and 2‐butylamine, respectively. The resulting calibration plots for the aliphatic amines were generally linear over about three orders of magnitude, with correlation coefficients >0.98. The LODs of amines decreased generally by one factor when SPE procedure, using BaCl₂/H₂SO₄ eluents, has been adopted. The proposed SPE procedure, seems to offer good results in terms of preconcentration, recoveries and cleanup of samples. The proposed methodology was successfully tested for the quantitative determination of some biogenic amines in beer and tuna.     

Qualitative gas chromatographic analysis of bacterial amines as their Schiff bases and other derivatives

Summary Columns of SE-30 and OV-17 on Chromosorb W, Apiezon N on Chromosorb G and Tenax-GC porous polymer were compared for their ability to separate bacterial amines converted to carbethoxy, dinitrophenyl, trimethylsilyl, Schiff base and fluorinated Schiff base derivatives.Tenax-GC performed less well than the other packings with respect to the number of plates and peak resolution. Dinitrophenyl and trimethylsilyl derivatives were both unsatisfactory for analysis of bacterial amines. Schiff bases and their fluorinated derivatives were found to be the most suitable. However, the former were preferred as the use of fluorinated Schiff bases confered little advantage when a flame ionization detector was employed. A maximum of 16 amines was separated, using columns of OV17 on Chromosorb W programmed from 110 °C to 280 °C at 5.5 °C min^–1 after an initial holding time of 6 min. The application of the method to analysis of cultures ofProteus mirabilis yielded two amines tentatively identified asiso-butylamine andiso-amylamine.     

Ion chromatographic determination of hydrolysis products of hexafluorophosphate salts in aqueous solution

In this work, hydrolysis of three different hexafluorophosphate salts in purified water was investigated. Aqueous samples of lithium hexafluorophosphate (LiPF₆), sodium hexafluorophosphate (NaPF₆) and potassium hexafluorophosphate (KPF₆) were prepared and stored for different times. Ion chromatography (IC) with UV as well as non-suppressed and suppressed conductivity detection was used for the analysis of the reaction products. For the detection and identification of the formed decomposition products, an IC method using IonPac AS14A 250 mm × 4.0 mm i.d. column and 2.5 mM KHCO₃–2.5 mM K₂CO₃ eluent was established. Besides hexafluorophosphate, four other anionic species were detected in fresh and matured aqueous solutions. The hydrolysis products fluoride (F⁻), monofluorophosphate (HPO₃F⁻), phosphate (HPO₄²⁻) and difluorophosphate (PO₂F₂⁻) were found and were unambiguously identified by means of standards or electrospray ionization mass spectrometry (ESI-MS). It was shown that stability of hexafluorophosphate solutions depends on the nature of the counter ion and decreases in the order potassium > sodium > lithium.     

Ion chromatographic determination of alkali and alkaline earth metals in mineral waters

Summary The rapid, simultaneous, suppressed ion chromatographic determination of alkali, alkaline earth metals and ammonium in highly mineralized waters has been examined using the novel cation exchange IonPac CS12 column. General ability for the determination of lithium, sodium, ammounium, potassium, magnesium, calcium and strontium in concentrations from a few g to several mg per liter was studied. The relative standard deviations of retention times of all seven cations were below 0.7% and the relative standard deviations of the measurements of peak areas and peak heights were mostly below 5%. Six natural mineral waters of different types were selected for evaluation of the method. It was not possible to determine lithium in the one run and ammonium usually partially coelutes with sodium precluding quantitative determination. Strontium was undetectable because of the necessary dilutions. All the reltionships between peak areas and concentrations or peak height and concentrations were linear and there was also no evidence of the effect of different matrices on the slope of regression lines.     

Amperometric detection of electroinactive anions using conducting polymer electrodes subsequent to chromatographic separation

The use of a chloride-containing polypyrrole electrode for the amperometric detection of electroinactive anions subsequent to separation by ion chromatography in suppressed, low conductivity eluent is described. It is demonstrated that changes in selectivity can be obtained by the application of different potential waveforms and current sampling protocols. The approach described is based on the anion dependence of the oxidation/reduction kinetics of the conducting polymer film induced by the applied potential.     

Gas chromatographic determination of aromatic amines in water samples after solid-phase extraction and derivatization with iodine II. Enrichment

A procedure for the enrichment of aromatic amines via solid-phase extraction was developed. A HR-P phase based on styrene–divinylbenzene was used for the investigations, generally followed by derivatization with iodine and determination via GC–ECD. The recoveries of 53 aromatic amines in a drinking water matrix at pH 9 were determined. Most anilines showed relative recoveries between 80–120% with relative standard deviations of ≤5% at concentration levels between 10 and 20 μg l⁻¹. The comparison with a wastewater matrix led to similar results. The enrichment procedure was applied to real samples, e.g., samples of ammunition wastewater.     

Response surface methodology to optimize gradient ion chromatographic separation of inorganic anions and organic acids in tobacco leaves

The separation optimization of nine organic and inorganic anions in tobacco leaves using gradient ion chromatography by response surface methodology was investigated.In order to achieve this goal the usefulness of the chromatographic response function(CRF) for the evaluation of the two different chromatographic performance goals(resolution and analysis time) was tested. The experiments were performed according to a Box-Behnken design response surface experimental design.     

离子色谱法同时分析啤酒中的有机酸和无机阴离子

建立了以NaOH-甲醇混合淋洗液,离子交换色谱柱,电导检测器检测,分离啤酒中有机酸和无机阴离子的离子色谱法.结果表明：在20 min内分离出啤酒中的11种主要有机酸与无机阴离子,方法回收率和相对标准偏差分别为96.30%～104.8%和0.02%～4.0%.