离子色谱法测定酒中叠氮根离子

建立了一种测定酒中叠氮化物的离子色谱方法(IC)。样品经稀释、过滤后,依次过OnGuard RP柱和OnGuard Na柱以除去疏水性物质和重金属离子的干扰。以KOH梯度淋洗,淋洗液流速为1.0 mL/min,采用DionexIonPacAS18色谱柱分离,IonPac TAC-UPL1预浓缩富集进样,最后用DS6电导检测器检测,外标法定量。N3-的线性范围为0.005~0.5μg/mL,线性相关系数为0.9998,加标回收率为88%~106%,检出限为0.002μg/mL(以信噪比S/N=3计),相对标准偏差为0.1%~0.6%。     

离子色谱法检测阿莫西林钠中二乙胺和三乙胺

建立了检测阿莫西林钠原料药中二乙胺、三乙胺的离子色谱法.色谱柱为Dionex CS17 (250×4mm),流动相为6mmol·L-1甲磺酸,流速为1.0mL·min-1,进样量为25μL,柱温为35℃,检测方式为抑制电导检测.结果表明:二乙胺和三乙胺的质量浓度线性范围分别为0.015 ～ 19.85μg·mL-1(r...     

Determination of sodium and ammonium ions in disproportionate concentration ratios by ion chromatography

In ion chromatography, samples of very different ammonium-to-sodium concentration ratios are difficult to quantify since these two cations have similar selectivities for stationary phases containing commonly used sulfonate or carboxylate cation-exchange functional groups. The IonPac CS15 cation-exchange column, with carboxylate and phosphonate functional groups as well as a crown ether group, was developed to address this limitation. Selectivity for the common inorganic cations on this column is different from that of conventional cation-exchange columns in that the separation between sodium and ammonium ions has been greatly increased, allowing for determinations of low levels of one in the presence of high levels of the other with an isocratic eluent. For larger than 4000:1 sodium-to-ammonium concentration ratios, an eluent step change or gradient elution is needed. For moderate ratios, combinations of this column with a carboxylate column, containing no crown ether group, can be used at room temperature with an isocratic eluent containing no organic solvent.     

Determination of microgram amounts of azide by gas chromatography

Azide ions (5–120 μg) are oxidized by cerium(IV) in an acidic medium. The nitrogen evolved is displaced by helium carrier and quantified by gas chromatography with a thermal conductivity detector. The relative standard deviation is <5%. Many sulphur anions, cyanide and some metal ions which form azide complexes do not interfere.     

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 organic anions in waste liquid of sodium hydrosulfite production by ion chromatography.

An ion chromatographic method for simultaneous determination of formate, hydroxyethyl sulfonate (HES), hydroxyethyl thiosulfate (HET), and coexisting anions in the industrial waste liquid of sodium hydrosulfite production was developed. The mixture of 1.6 mmol/l of phthalic acid and 1.2 mmol/l tri-(hydroxyethyl) aminomethane was used as eluent. The interference of coexisting sulfite anion with HES was avoided by selective oxidation with hydrogen peroxide as oxidizer. The other coexisting inorganic anions, Cl-, SO4(2-) and S2O3(2-) can be determined simultaneously. The linear range of the peak area calibration curves for all analytes was up to two or three orders of magnitude. The detection limits (S/N = 3) for formate, HES and HET were 2.4, 1.0 and 0.5 mg/l, respectively. The recoveries for all analytes were 91.61-100.6%.     

Determination of sodium,potassium, calcium and magnesium cations in biodiesel by ion chromatography

This work reports an ion chromatographic (IC) method for the quantitative determination of inorganic cations (Na⁺, K⁺, Mg²⁺ and Ca²⁺) in biodiesel samples that were synthesized from different vegetable oils and fat. The proposed method uses water extraction, heating and ultrasound. The limits of detection (LOD) for each ion, in milligrams of the analyte per kilogram of biodiesel (mg kg⁻¹), were respectively: 0.11 (Na⁺); 0.42 (K⁺); 0.23 (Ca²⁺); and 0.36 (Mg²⁺). The accuracy of the method was studied through recovery tests. For comparison, two samples were also analyzed using an Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) procedure. The paired Student t test and the Snedecor F test showed that both methods offer equivalent results in terms of accuracy and precision. The operational simplicity, accuracy and precision of the proposed method suggest that it can be a good alternative for the determination of inorganic cations in biodiesel samples.     

Determination of biogenic amines in alcoholic beverages by ion chromatography with suppressed conductivity detection and integrated pulsed amperometric detection

The determination of biogenic amines in alcoholic beverages is important to assess the potential risks associated with the consumption of high concentrations of these compounds. In addition, product storage conditions and the length of storage can cause the formation of biogenic amines that reduce product quality. We report a new method using cation-exchange chromatography with either suppressed conductivity, integrated pulsed amperometry, UV, or a combination of these detection techniques to determine biogenic amines in alcoholic beverages. The main objective was to provide a direct comparison between IPAD and suppressed conductivity detection for determining biogenic amines in alcoholic beverages. Suppressed conductivity is the simplest detection approach for determining putrescine, cadaverine, histamine, agmatine, phenylethylamine, spermidine, and spermine with good sensitivity (0.004-0.08 mg/l) and was used to evaluate the influence of storage time and conditions on the evolution of biogenic amines in alcoholic beverages. Integrated pulsed amperometric detection (IPAD) detects more biogenic amines than suppressed conductivity detection, enabling the detection of dopamine, tyramine, and serotonin. Tyramine was simultaneously determined by UV detection and IPAD to provide confirmation and ensure the accuracy of the analytical results. The linearity of biogenic amine responses was within 0.1-20 mg/l and peak area precisions were 0.24-4.97% for IPAD, suppressed conductivity-IPAD, and UV detection. The sensitivity for the 10 biogenic amines using the 3 detection techniques varied considerably from 0.004-1.1 mg/l and recoveries were within 85-122%.     

食品中亚硫酸盐的离子色谱法测定

建立了食品中亚硫酸盐的离子色谱检测方法. 样品采用40 mmol/L NaOH溶液提取, 甲醛作稳定剂, 经ENVI-Carb活性碳小柱除去提取液中的色素, 石油醚除去提取液中的油脂, 用配有电导检测器的离子色谱仪测定. 以AS9-HC为色谱柱, 流动相为8 mmol/L Na2CO3-2.5 mmol/L NaOH, 亚硫酸盐的残留量在0～6.0 mg/L的范围内线性关系良好, 相关系数为0.9989, 相对标准偏差为1.3%～9.1%, 回收率在88.4%～98.1%之间.     

离子色谱法测定土壤中植物激素乙烯利

土壤样品中的乙烯利在IonPac AS14分离柱（4mm）,（3．5mmol Na2CO3＋1．0mmol NaHCO3）／L淋洗液的淋洗条件下得到较好的分离。在0～10μg／mL的范围内标准曲线呈线性,检出限为（0．08μg／mL）。精密度好,10．266μg／mL时,保留时间的RSD=0．86％;峰高的RSD=1．1％;峰面积的RSD=1．0％。在此条件下,其它阴离子对乙烯利的检测不干扰,样品的加标回收率为85．6％～87．9％。     

Determination of lithium in wines by ion chromatography

Lithium ion can be added as a denaturing agent to wines unsuitable for consumption. Accuracy of flame atomic emission spectroscopy with direct nebulization, which is commonly adopted for discovering illegal use of denatured wines, was found to be compromised by Na+, K+, NH4+, Mg2+, Ca2+ and ethanol contained in wine. Ion chromatography (IC) was tested in order to propose an alternative method for legal controls. Experimental design was used to investigate the influence on the accuracy of the determination of Li+ at ppb levels, of Na+ and ethanol content of wine and of fluctuations of eluent flow-rate and composition. It turned out that IC quantification of Li+ can be affected by eluent parameters rather than by wine composition. Since the former can be maintained under the operators control, while the latter cannot, IC was judged preferable to AES for legal controls of Li+ in wines.     

Determination of moniliformin in maize by ion chromatography

An ion chromatographic method for the determination of the mycotoxin moniliformin in maize was developed. The method contains a fast and simple clean-up procedure, which allows high volume sample injection. No further pre-concentration step is required. The limit of quantification was estimated to be 0.12 mg/kg moniliformin in maize. In contrast to the two previously published ion chromatographic methods, the moniliformin peak is base line separated and occurs in a region of a smooth base line in the ion chromatogram. The newly developed method showed a recovery through the whole analytical procedure of 97+/-3.5 %, whereas most previously described analytical methods had recoveries in the 70% range.     

Determination of anions in high-purity water by ion chromatography

Summary The determination of the concentration of some different anions in high-purity water (g/l-level) using ion chromatography after concentration on pre-columns is described. The detection ist made by a conductivity cell after passing an anion fiber-suppressor (AFS). Two different separator columns (AS-5 and AS-4) and some different separator systems were tested. In all cases linearity is given for the determined anions.The concentration of the anions was determined not directly but by addition of a standard solution and subsequent graphic extrapolation of the calibration diagram. The determination levels are below 1 g/l. The AS-5 column gives better results than the AS-4 column.

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Ionen-chromatographische Bestimmung von Anionen in Reinstwasser

Zusammenfassung Die Bestimmung der Konzentration verschiedener Anionen in Reinstwasser (g/l-Bereich) mittels der Ionen-Chromatographie nach Anreicherung auf Konzentriersäulen wird beschrieben. Die Detektion erfolgt über eine Leitfähigkeitsmeßzelle mit vorgeschaltetem Anionen-Hohlfasermembransuppressor (AFS). Es wurden zwei verschiedene Trennsäulen (AS-4 und AS-5) und mehrere Trennsysteme getestet und optimiert. In allen Fällen ergab sich Linearität für die untersuchten Anionen. Die Bestimmung der Anionenkonzentrationen in Reinstwasser erfolgte nicht direkt, sondern durch Aufstocken mit Standardlösung und anschlie\ender graphischer Extrapolation der erstellten Eichgraden. Die Nachweisgrenzen liegen unter 1 g/l. Die AS-5-Säule erwies sich für die beschriebene Methode als geeigneter.

     

Determination of anions in landfill leachates by ion chromatography

Ion chromatography has been used to determine inorganic and organic anions within landfill leachates. Two procedures are operated on split samples which have multiple dilutions and vary in sample treatment: gradient ion-exchange chromatography for inorganic anions and isocratic ion-exclusion chromatography for organic anions. Interference between carbonate and organic acid anions using ion-exclusion chromatography is avoided by treatment with octanesulphonic acid eluent. Using ion-exchange chromatography, the presence of valerate, hexanoate and heptanoate is checked (but not quantified) for a subsample which has been treated to remove chloride; these species are then determined by ion-exclusion chromatography. Analysis of certified standards (10 mg/1 certified VFA standard; Supelco, Bellefonte, PA, USA; 20–150 mg/l inorganic anions, ICMIX1-100, Glen Spectra Reference Materials, Middlesex, UK) gives good agreement (within 5% for organic anions except formate, and within 1% for inorganic anions), with R.S.D. values for all anionic species varying from 0.44–2.23.     

离子色谱法检测盐酸头孢吡肟中的N-甲基吡咯烷

建立了一种盐酸头孢吡肟中的N-甲基吡咯烷的离子色谱分析方法.采用阳离子交换柱IonPac CS12A作分析柱,甲烷磺酸-乙腈为淋洗液,外加水电抑制模式,电导检测,在10 min内即可完成分析.线性良好(r2=0.9985),样品的RSD在5%以下(n=6),回收率在89.5%～108.4%之间.方法可在盐酸头孢吡肟产品的检验中发挥作用.     

Determination of ammonium in seawater by column-switching ion chromatography

A system which combines column switching and concentration was developed. A binary eluent mechanism was developed to study the effect of high sample concentration matrix on retention time shifts of the trace analyte. Separation conditions were chosen according to this mechanism to reduce the retention time shift of ammonium in the presence of high concentration sodium ion: high concentration sulfuric acid (25 mmol/l) was used as the eluent, and a hydronium-selective column of high capacity--a CS12 column, was employed. Since the retention time shift was reduced, the interval between onset and the complete elution of a high concentration ammonium standard (10 mg/l) was directly defined as the column-switching time window, which greatly simplified the procedure for determining the time window. Results showed that for ammonium below 1 mg/l, 90% ammonium was introduced and concentrated. Detection limits of 12.8 microg/l were obtained for ammonium with sodium at 1000 mg/l.     

Determination of ethanol in alcoholic beverages by liquid chromatography using the UV detector

Ethanol in certain beverages and in similar solutions may be determined by reversed-phase liquid chromatography (LC) using the UV detector. The mobile phase in this indirect photometric detection technique contains a low concentration of a UV-absorbing compound, such as acetone, that coelutes with the ethanol peak. Several variables such as the choice and concentration of the UV-detection agent are examined regarding their effects on the retention time, magnitude and linearity of peak area, and other aspects of quantitation. Except for filtering to remove particulate matter, samples can be injected without pretreatment. The concentration of ethanol in several types of beverages can be determined with 2% relative standard deviation, calibration is linear to 40% ethanol, and the minimum detectable concentration is 0.1%.     

离子对分离和抑制电导检测法测定四乙基铵和四丁基铵根离子

建立了季铵盐的离子色谱分析方法.采用Dionex DX-500 型离子色谱仪,C18柱,电导检测器,以30%乙腈和10 mmol/L甲烷磺酸混合溶液为流动相,流量为1.00 mL/min.四乙基溴化铵和四丁基溴化铵的质量浓度和峰面积的相关系数分别为0.9996和0.9994;线性范围分别为10～80 mg/L和20～120 mg/L;检出限分别为0.28和0.76 mg/L;RSD分别为1.3%、 2.5%.该方法可用于分析水溶液中季铵盐的含量.