离子色谱法测定水中4种有机酸

建立了水样中甲酸、乙酸、丙烯酸和甲基丙烯酸的离子色谱测定方法,采用IonPac AS11-HC阴离子分离柱,以KOH为淋洗液,采用浓度梯度洗脱,可同时测定上述4种有机酸。方法对实际水样中甲酸、乙酸、丙烯酸和甲基丙烯酸的平均加标回收率在80.2%~103.3%,相对标准偏差在5.8%之内,检出限分别为:0.005,0.003,0.005和0.004mg/L;定量下限分别为:0.020,0.012,0.020和0.016mg/L。方法准确、简便、环保,能够满足实际水样的测定需要,且水样中常见的阴离子不会对目标污染物的测定产生影响。     

阀切换-离子色谱法测定1,2-环氧丁烷产品中有机酸

建立了阀切换-离子色谱法测定1,2-环氧丁烷（1,2-BO）产品中有机酸（甲酸、乙酸和丙酸）的方法。样品经乙醇稀释后,通过阀切换技术,有机酸被IonPac TAC-ULP1捕集柱捕集,然后进入IonPac AS11分析柱分离,并由电导检测器检测。结果表明：甲酸、乙酸和丙酸均能实现较好地分离,在各自的范围内其色谱峰面积呈现良好的线性关系。实际样品的加标回收率为92.5%~111.8%,相对标准偏差小于5.6%（n=3）,检出限为0.60~4.80 μg/L。该方法具有前处理简单、快速、准确等特点,适用于不溶于水的有机体系中有机酸的分析。     

离子排斥色谱法测定环境样品中挥发性有机酸及乳酸

提出了同时测定环境样品中挥发性有机酸及乳酸的离子排斥色谱法（IEC法）。考察了流动相浓度、流速对有机酸分离的影响。实验结果表明,乳酸、甲酸、乙酸、丙酸、正丁酸和正戊酸可达到完全分离,被测组分的浓度与其峰高在一定的范围呈良好的线性关系,检出限均低于0.10 mg/L。测定了糖蜜酒精废水和消化污泥中有机酸的含量,结果满足检...     

Photoassisted vapor generation in the presence of organic acids for ultrasensitive determination of Se by electrothermal-atomic absorption spectrometry following headspace single-drop microextraction

A method is described for the determination of selenium at the pg/mL level by electrothermal-atomic absorption spectrometry using in situ photogeneration of Se vapors, headspace sequestration onto an aqueous microdrop containing Pd(II) and subsequent injection in a graphite tube. Several organic acids (formic, oxalic, acetic, citric and ethylenediaminetetraacetic) have been tried for photoreduction of Se(IV) into volatile Se compounds under UV irradiation. Experimental variables such as UV irradiation time, organic acid concentration, Pd(II) concentration in the drop, sample and drop volumes, extraction time and pH were fully optimized. Low-molecular weight acids such as formic and acetic provided optimal photogeneration of volatile Se species at a 0.6 mol/L concentration. Citric and ethylenediaminetetraacetic acid allowed to use a concentration as low as 1 mmol/L, but extraction times were longer than for formic and acetic acids. Photogeneration of (CH₃)₂Se from Se(IV) in the presence of acetic acid provided a detection limit of 20 pg/mL, a preconcentration factor of nearly 285 and a precision, expressed as relative standard deviation, of 4%. Analytical performance seemed to depend not only on the photogeneration efficiency obtained with each acid but also on the stability of the vapors in the headspace. The method showed a high freedom from interferences caused by saline matrices, but interferences were observed for transition metals at a relatively low concentration.     

Determination of organic acids in air by capillary electrophoresis and ion-exclusion chromatography

Summary A capillary electrophoretic (CE) method for the determination of organic acids in the low ppm range is described. The buffer consisted of 5 mM 2,6-pyridinedicarboxylic acid and 0.5 mM cetyltrimethylammonium bromide, pH 5.6. The former served as background electrolyte for indirect UV detection at 200 nm, whereas the latter was used to reverse electroosmotic flow. In <5 min 8 low molecular mass organic acids (oxalic, formic, malonic, glutaric, glycolic, acetic, lactic and propanoic) and two inorganic acids (hydrochloric and sulphuric) were separated. Detection limits for anions tested were 0.04 mg L⁻¹ (lactic acid) to 0.6 mg L⁻¹ (malonic acid). The method was applied to the determination of organic acids in air samples. The CE results when compared with ion-exclusion chromatography (IEC) agreed well. The use of electrokinetic injection in CE proved beneficial for preconcentration of organic acids in real samples. Using electrokinetic injection, preconcentration factors ranging from 14 (hydrochloric acid) to 3 (propanoic acid) were obtained. Presented at Balaton Symposium on High-Performance Separation Methods, Siófok, Hungary, September 1–3, 1999     

胶束电动毛细管色谱-间接紫外检测法测定糖蜜酒精废液中的有机酸

建立了一种利用胶束电动毛细管色谱-间接紫外检测法同时测定丙二酸、甲酸、酒石酸、苹果酸、琥珀酸、戊二酸、乙酸、乳酸和谷氨酸的新方法。以7.5 mmol/L邻苯二甲酸氢钾-1.5 mmol/L十六烷基三甲基溴化铵(用0.1 mol/L氢氧化钠调pH至6.50)混合液作为电泳介质,检测波长为300 nm,参比波长为210 nm,未涂层弹性石英毛细管(50 μm i.d.×64 cm)为分离通道,在6 min内实现了9种酸的完全分离。9种有机酸的浓度与其峰面积在一定的范围呈良好的线性关系,检出限均低于1.5 mg/L,迁移时间和峰面积的日内、日间相对标准偏差均小于6%。该法用于糖蜜酒精废液中有机酸的测定,结果令人满意,9种有机酸的样品加标回收率均在93%以上。     

离子排斥色谱法同时测定果汁中11种有机酸

 用离子排斥色谱法实现了对果汁中 11种有机酸 (草酸、柠檬酸、酒石酸、苹果酸、抗坏血酸、乳酸、琥珀酸、甲酸、乙酸、戊二酸、富马酸 )的分离测定。以 17mmol/L硫酸为淋洗液 ,样品在ICE ION 30 0离子排斥柱上分离后 ,用紫外检测器在 2 10nm处测定其中的有机酸。各组分质量浓度测定的相对标准偏差在 1.5 %～ 9.8% (n =10 )。     

Determination of volatile fatty acids in landfill leachates by ion-exclusion chromatography

An ion-exclusion chromatographic method with on-line desalinization for the determination of volatile fatty acids in landfill leachates is described. Highly sensitive conductivity detection of the organic acids was achieved by using dilute p-hydroxybenzoic acid solution as an eluent. Interference with mineral acids was reduced by treatment with barium chloride solution prior to desalinization. A silver-loaded cation-exchange guard column for the desalinization was installed in series with the analytical column to avoid the contamination of organic acids. This method features detection limits of 0.01 mg L(-1) formic acid, 0.02 mg L(-1) acetic acid, 0.05 mg L(-1) propionic acid, and 0.1 mg L(-1) butyric acid, respectively, with an injection of 20 microL sample. Application of the on-line desalinization LC method is illustrated for leachate samples from a Japanese sanitary landfill.     

二维阀切换离子色谱法测定海带中游离氨基酸

建立一种测定海带中游离氨基酸的阀切换高效阴离子交换色谱耦合脉冲安培检测器法。采用一根阳离子交换柱对氨基酸进行富集,而后经阀切换至氨基酸分析柱Amino Pac~PA-10(250 mm×2 mm)上分离并进入安培检测器检测。在最佳分离条件下,20种氨基酸的质量浓度在0.1~20.0 mg/L范围内与其色谱峰面积线性关系良好,线性相关系数r~20.99,20种氨基酸的检出限为0.01 mg/L,加标回收率为83.12%~117.34%,测定结果的相对标准偏为1.02%~13.05%(n=8)。该方法样品前处理简单,无基底杂质干扰,适用于海带样品中游离氨基酸的测定。     

反相高效液相色谱法同时测定咖啡豆中的6种酚酸类化合物

建立了同时测定咖啡豆中6种酚酸类化合物(咖啡酸、3-咖啡酰奎尼酸、4-咖啡酰奎尼酸、5-咖啡酰奎尼酸、3,5-二咖啡酰奎尼酸、4,5-二咖啡酰奎尼酸)的反相高效液相色谱测定方法。采用Kromasil C18柱(200 mm×4.6 mm, 5 μm),以乙腈和0.1%甲酸水溶液为流动相进行梯度洗脱,二极管阵列检测器检测,45 min内可对6种目标物进行同时检测,且各化合物都能达到基线分离。经测定,样品中6种酚酸类化合物的加标回收率为90.76%～104.73%,相对标准偏差为0.7%～3.9%。该法简便、快速、灵敏度高,适用于咖啡豆中6种酚酸类化合物的同时分析以及咖啡豆原料与制品的质量控制和综合评价。     

离子色谱法及聚类分析研究主流烟气中的有机酸

建立了超声辅助萃取-离子色谱法同时测定卷烟主流烟气中主要有机酸的方法.采用20 mL 30 mmol/L J NaOH溶液在50℃下对捕集了卷烟主流烟气的剑桥滤片超声萃取50 min,AS11-HC分离柱、Ion AG11-HC保护柱、ASRS-ULTRAⅡ抑制器,KOH溶液为淋洗液,用电导检测器同时测定了卷烟主流烟气中的乳酸、甲酸、乙酸、丙酸、苹果酸和草酸的含量.方法的线性范围1.0～400 mg/L,相关系数为0.9990～0.9995,相对标准偏差1.4%～4.8%,检出限0.03～0.09 mg/L,回收率为92%～104%.采用此方法测定了19种不同规格卷烟样品主流烟气中6种有机酸的含量,并且以6种有机酸为指标对样品进行了聚类分析.结果表明,6种有机酸的含量分布特征可反映不同等级卷烟产品的特性,可用于不用等级卷烟产品的比较和分类.     

阴离子交换离子色谱法测定乳酸催化制备的丙烯酸

通过乳酸催化脱水制备丙烯酸具有良好的应用前景。为了对其中的催化过程进行有效、及时的监控,建立了一种同时测定乳酸及丙烯酸的阴离子交换色谱法(AEC)。选择Metrohm A Supp 5阴离子交换柱(150 mm×4.0 mm),以2 mmol/L Na2CO3+2 mmol/L NaHCO3混合水溶液为流动相,采用化学抑制电导检测技术,乳酸和丙烯酸在6 min内即可实现完全分离。乳酸和丙烯酸工作曲线的线性范围分别为0.1～500 mg/L和0.1～200 mg/L,检出限分别为0.030 mg/L和0.035 mg/L,加标回收率分别为100.7%～106%和99.6%～103%,相对标准偏差分别为2.16%~2.49%和2.42%~2.48%。该方法准确、快速、灵敏、重现性好。     

Development of a Simple,Underivatized Method for Rapid Determination of Free Amino Acids in Honey Using Dilute-and-Shoot Strategy and Liquid Chromatography-Tandem Mass Spectrometry

A simple, fast and reliable analytical method was developed for 20 free amino acids (FAAs) determination in honey samples through a dilute-and-shoot strategy and hydrophilic interaction liquid chromatography tandem mass spectrometry. Compared with previous reports, direct dilution by water has significantly reduced the matrix effect and facilitated full extraction of FAAs. Further, a 5 min determination method was established with an acetonitrile–water mobile phase system with 0.1% formic acid addition. The established method was validated and demonstrated several advantages including short detection time, wide linear range over 3–4 orders of magnitude, high sensitivity down to 0.1 ng/mL and negligible matrix effect. Twenty FAAs were determined in 10 honey samples from different botanical origins by this method, and 19 FAAs were found. This general applicable method was also promising for fast determination of FAAs in other practical samples.     

毛细管电泳法同时分析水、乳、膏类化妆品中5种有机酸

建立了毛细管电泳同时分析5种有机酸的间接紫外检测法。优化了背景电解质溶液中表面活性剂十四烷基三甲基溴化铵（TTAB）的浓度和溶液pH。优化后的电泳分析条件如下：含0.4 mmol/L TTAB的15 mmol/L邻苯二甲酸氢钾溶液为背景电解质（pH 5.6）；分离电压-15 kV；检测波长254 nm；分离温度25℃；进样压力5 kPa；进样时间5 s。在此条件下，可在6 min内完成5种有机酸的同时分离检测，线性范围为甲酸15~600 mg/L、苹果酸30~800 mg/L、柠檬酸20~700 mg/L、乙醇酸40~500 mg/L和乳酸30~5000 mg/L，线性相关系数为0.9983~0.9998；检出限为0.1~2.0 μg/g。该方法可用于检测水状、乳状、膏状3类化妆品中的5种有机酸。在3个加标水平下，有机酸分析的回收率为95.0%~101.6%，RSD在2.0%以内。该方法操作简单，分析快速，安全环保，灵敏度高，重现性好，有望用于化妆品生产和保存过程中有机酸的监测。     

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.     

尿中有机酸的毛细管气相色谱—质谱轮廓分析—用于苯丙酮尿症的诊断

应用毛细管气相色谱-质谱轮廓分析方法,测定了33例2.5～4.5岁健康儿童尿中有机酸种类及含量和8例拟诊为苯丙酮尿症儿童尿中的有机酸,结果表明患儿尿样中苯丙酮酸、苯乙酸、邻羟基苯乙酸、对羟基苯乙酸高于正常值10～470倍。为苯丙酮尿症的确诊提供了可靠方法。     

离子排斥色谱法测定甘油催化氧化产物中的H2CO3和HCOOH

建立了测定甘油催化氧化产物中H2CO3和HCOOH的离子排斥色谱分析方法。采用离子排斥柱分离,分别用纯水和4 mmol/L HCl作流动相进行H2CO3和HCOOH的分析。检测方式为非抑制电导检测。实验结果显示,H2CO3和HCOOH工作曲线的线性范围为2～100 mg/L和6.23～124.6 mg/L,检出限分别为0.45 mg/L和2.49 mg/L(S/N=3)。H2CO3的保留时间和峰面积的相对标准偏差分别为0.07%和4.0%,HCOOH的保留时间和峰面积的相对标准偏差分别为0.09%和2.2%。方法已用于甘油催化氧化产物中H2CO3和HCOOH的分析。     

油田水中短链有机酸的等速电泳法研究

本文采用水相蒸发除去大量的氯离子,用等速电泳法对油田水中短链有机酸进行了定性定量分析。结果表明,油田地层水中有机酸成分主要有甲酸、乙酸、丙酸、丁酸、苯甲酸和乳酸等,本法回收率和相对标准偏差分别在96％～105％和2.4％～7.6％之间。     

Gas-chromatographic determination of formic acid in the oxidation products of organic substances

Procedures for the gas-chromatographic determination of formic acid in oxidation produts of organic substances after its conversion to benzyl formate were developed. In determining formic acid in an organic phase, free formic acid was esterified with benzyl alcohol in a pyridine solution while adding acetic anhydride under mild conditions. The conversion of formic acid was complete even in the presence of other mono-and dicarboxylic acids in considerable amounts. It was found that the formation of benzyl formate occurred via a mixed aldehyde formed in situ from formic acid and acetic anhydride. The determination of formic acid in aqueous solutions involves the synthesis of its sodium or potassium salt and the successive treatment of this salt with acetyl chloride and benzyl alcohol in a pyridine solution.     

单柱阴离子色谱法同时测定无机阴离子、无机阳离子和有机酸的研究

自Small等首次采用双柱阴离子色谱法测定无机阴离子以来,单柱阴离子色谱法已被用于测定无机阴离子、有机酸,并利用金属阳离子与EDTA形成的阴离子配合物分离测定阳离子。但用单柱阴离子色谱法同时测定无机阴离子、无机阳离子和有机酸尚未见报道。本文采用EDTA为淋洗液的单柱阴离子色谱法研究了无机阴离子、无机阳离子和有机酸的同时分析测定。