离子排斥色谱法分析有机酸和无机弱酸

用非抑制型电导检测的离子排斥色谱法,以对甲苯磺酸为淋洗液,研究了柠檬酸、苹果酸、抗坏血酸、乙醇酸、甲酸、乙酸、丙酸及氢氟酸和碳酸的色谱分离及定量检测条件。     

小麦根系中有机酸的离子色谱法分析研究

研究了离子交换和离子排斥法用于小麦根系中有机酸分析的色谱条件,首次建立了植物报系中有机酸的高子色谱分析方法。分别用Ｎａ＿２ＣＯ＿３／ＮａＨＣＯ＿３,Ｎａ＿２ＣＯ＿３／ＮａＯＨ和ＨＣｌ作离子交换和离子排斥分高的流动相,选用化学抑制型电导检测器。对样品中柠檬酸、苹果酸、丁二酸、反丁烯二酸、乙酸、草酸的检测限为Ｏ１～０．５μｇ／ｍＬ,相对标准偏差为１．７８％～２．９７％,样品加标回收率为１００±１０％。     

Generation of Hydrogen from Photolysis of Organic Acids by Photosynthetic Bacteria

Photodccomposition of ten kinds of organic acids by Rhodopseudomonas palustris for producing hydrogen has been investigated,By using acctate as hydrogen donor,dynamics of hydrogen production and cell growth has been determined;the influences of acetate concentration,temperature,light intensity and the effects of the ineraction among metal ions (Fe^3 ,Ni^ ),acctate and glutamatc in aqueous solution on hydrogen production have been examined for optimizing the conditions of H2 generation .The results show that H2 production is partially correlated with cell growth ;Ni^2 inhibits hydrogen production,but enhances cell growth; Fe^3 promotes hydrogen production evidcntly,The highest rate of H2 production is 22.1 mL L^-1h^-1 under the conditions of 35-37℃,6000-8000lx,30 mmolL^-1 of acetate, 9mmolL^-1 of glutamate, and 50μmolL^-1 of Fe^3 .     

Determination of Organic Compounds,Fulvic Acid,Humic Acid,and Humin in Peat and Sapropel Alkaline Extracts

Black, brown, and light peat and sapropel were analyzed as natural sources of organic and humic substances. These specific substances are applicable in industry, agriculture, the environment, and biomedicine with well-known and novel approaches. Analysis of the organic compounds fulvic acid, humic acid, and humin in different peat and sapropel extracts from Lithuania was performed in this study. The dominant organic compound was bis(tert-butyldimethylsilyl) carbonate, which varied from 6.90% to 25.68% in peat extracts. The highest mass fraction of malonic acid amide was in the sapropel extract; it varied from 12.44% to 26.84%. Significant amounts of acetohydroxamic, lactic, and glycolic acid derivatives were identified in peat and sapropel extracts. Comparing the two extraction methods, it was concluded that active maceration was more efficient than ultrasound extraction in yielding higher amounts of organic compounds. The highest amounts of fulvic acid (1%) and humic acid and humin (15.3%) were determined in pure brown peat samples. This research on humic substances is useful to characterize the peat of different origins, to develop possible aspects of standardization, and to describe potential of the chemical constituents.     

烟草中挥发性和非挥发性有机酸的快速测定

建立了气相色谱-质谱(GC-MS)法快速测定烟草中22种非挥发性、挥发性有机酸的分析方法。采用对甲苯磺酸-硫酸-甲醇(PTSA/H2SO4/CH3OH)酯化试剂对烟草样品进行一次酯化,生成的有机酸酯用GC-MS进行分析。结果表明,酯化时间从20 h缩短到1 h,非挥发酸回收率在93.4%~103.2%之间,相对标准偏差(RSD)小于4.2%;挥发性有机酸回收率在89.2%~99.1%之间,RSD小于3.5%。该方法具有简便、快速,结果准确等特点,用于测定部分烟草样品的挥发性、非挥发性有机酸,取得了满意的结果。     

Determination of Organic Acids in Ground Water by Liquid Chromatography/Atmospheric Pressure Chemical Ionization/Mass Spectrometry

ABSTRACT

Current methods of determining organic acids in ground water are labor-intensive, time-consuming and require a large volume of sample (100 milliliter to 1.0 liter). This paper reports a new method developed to determine aliphatic, alicyclic, and aromatic acids in ground water using liquid chromatography/atmospheric pressure chemical ionization/mass spectrometry (LC/APCI/MS). This method was shown to be fast (less than 1 hour), effective, and reproducible, requiring only 1.0 mL of ground-water sample. Ground water was pH-adjusted, filtered through 0.45 μm filters and directly injected into the LC. A binary solvent system consisting of 40 mM of aqueous ammonium acetate and methanol and a C18 column were used for chromatographical separation. The APCI was operated under negative ionization mode. Selected ion monitoring (SIM) was used for detection and quantitation of the analytes. This method was applied to the analysis of organic acids in ground-water samples collected from an aquifer contaminated with JP-4 fuel hydrocarbons at Wurtsmith Air Force Base in Oscoda, Michigan. Aromatic acids identified in the contaminated ground water include o-, m-toluic acids (2- and 3-methylbenzoic acids), 2,6-dimethylbenzoic acid, 2,3,5- and 2,4,6-trimethylbenzoic acids and two additional trimethylbenzoic acids with unknown location of methylation. The detection of aromatic acids in groundwater from the KC-135 site provided evidence for in situ microbial degradation of hydrocarbons occurring in the aquifer.     

临床化学上氨基酸、有机酸及核苷类的二维薄层色谱多相分离

在同一块薄层板上多相二维分离３０余种氨基酸、４０余种非挥发性有机酸和２０余种碱基。核苷类化合物。应用一对新的展开剂,用紫外灯－吖啶试剂－镉茚三酮试剂组合显色定位分析,改良了尿液非挥发性有机酸的溶剂萃取。尿液中此三类化合物提取物的多相二维色谱分离效果良好。     

离子交换色谱法同时测定啤酒中有机酸和无机阴离子

建立了用亲水性阴离子交换分离柱,KOH为淋洗液等浓度泵作梯度淋洗,电导检测,同时分离和检测16种无机阴离子和低分子量有机酸的离子色谱法。方法对所测无机阴离子和有机酸检出限在9．3～32μg/L之间;线性范围均在2个数量级以上;回收率在90．2％～107．2％之间。方法用于啤酒样品的分析,结果满意,样品的RSD小于5．3％(n=7)。     

气相色谱法测定饮料酒中的低沸点有机酸

在非质子极性溶剂-二甲基乙酰胺中,室温下用碘乙烷与C_1—C_6脂肪酸及乳酸的四甲基铵盐反应制备各酸相应的乙酯。乙酯在15%的邻苯二甲酸二壬酯与6%的土温-80混合固定液填充柱上获得满意分离。用本法测定饮料酒中的低沸点有机酸含量,简便、快速、准确。     

高效液相色谱法测定植物根系分泌物中的有机酸

以小麦为例,建立了植物根系分泌物中有机酸的提取和测定方法。小麦根系分泌物由培根法培育收集,先后经阳离子和阴离子交换树脂提取,旋转蒸发至干后用pH 2.1的稀HClO4溶液溶解、定容,以5 mmol/L H2SO4水溶液为流动相,经Bio-Rad Aminex HPX-87H阳离子交换树脂柱分离,在波长210 nm处紫外检测。在小麦根系分泌物中,有机酸的检测限为1~120 μg/L,日内检测精密度为1.2%~4.7%,日间检测精密度为3.3%~10.6%,不同剂量的加标回收率为82.0%~96.2%,相对标准偏差为0.67%~3.31%。该方法简便快速,灵敏可靠,适用于介质复杂的环境样品中有机酸的测定。     

烟草中9种有机酸的梯度离子色谱法测定研究

采用淋洗液自动发生一梯度离子色谱分离,电导检测法分离测定了烟草中的甲酸、乙酸、乳酸、丙酸、丁酸、苹果酸、丙二酸、草酸和柠檬酸,并研究了9种有机酸在阴离子交换色谱中的保留行为.以淋洗液自动发生器生成的KOH为淋洗液,样品经提取、过滤稀释后,在IonPac AS1l-HC阴离子交换色谱柱上分离,抑制电导检测器进行检测,一次...     

反相高效液相色谱法测定山楂中的有机酸

采用Hypersil ODS2(4.6 mm×250 mm,5μm)色谱柱,以磷酸盐缓冲溶液(pH=2.6)为流动相,流速0.8 mL/m in,检测波长210 nm,建立了山楂中柠檬酸、苹果酸等有机酸的高效液相色谱分析方法。其中柠檬酸和苹果酸的线性范围分别为0.50~50.04μg、0.10~10.00μg;3个浓度水平的回收率分别为95.5%~96.6%、100.2%~103.7%,RSD分别为0.11%~0.38%、0.41%~2.53%;检出限分别为0.04μg、0.03μg(S/N=3)。测定了5种不同产地山楂果肉及山楂核中的柠檬酸、苹果酸的含量。所建立的方法快速、灵敏度高、重复性好,可用于山楂中有机酸的测定。     

Physicochemical Properties and Functional Characteristics of Ecologically Extracted Shrimp Chitosans with Different Organic Acids during Demineralization Step

The current study aims to develop eco-friendly and economical chitosans with a wide range of applications using organic acids for shrimp shells demineralization. Chitosan samples were extracted from shrimp (Parapenaeus longirostris) shells and the demineralization step was performed with three organic acids (citric, acetic, and lactic) and two mineral acids (hydrochloric and sulfuric). The chitosans were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The chitosans’ physicochemical properties were also determined. The characteristic bands and functional groups of the chitosans were identified by FTIR spectra. The chitosans’ crystallinity order was as follows: Ch_HCl > Ch_Citric > Ch_H2SO4 > Ch_Lactic > Ch_Acetic. The chitosans’ morphological characteristics revealed a smooth surface and fibrous structures with pores. Chitosans extracted by organic acids showed the highest extraction yields. Ch_HCl and Ch_Citric had higher degrees of deacetylation values; 83.67% and 81.47%, respectively. The solubility was proportional to the degree of deacetylation. Furthermore, Ch_H2SO4 and Ch_Citric had lower molecular weight values; 149 kDa and 183 kDa, respectively. Organic acids are as effective as mineral acids for shrimp shells demineralization. The developed process opens up possibilities to produce chitin and chitosan in a more eco-friendly way and at a lower cost in many industrial sectors.     

烘丝前后烟丝多元酸和高级脂肪酸变化研究

烟草中的多元酸对抽吸品质有重要影响,它们能与生物碱结合成盐,调节烟草中碱性成分的挥发性。高级脂肪酸可分成饱和与不饱和两类,饱和脂肪酸能增加烟气的脂肪味、腊味并使之圆和;不饱和脂肪酸增加烟气的丰满度和粗糙感。卷烟在烘丝过程中由于温度、湿度的变化而引起烟草内部化学成分的变化。本文应用甲酯衍生化和GC-MS法,对卷烟加工过程中烘丝工序前后的多元酸和高级脂肪酸进行了定性定量分析。为卷烟配方和加工工艺参数的优化提供理论依据。     

Organic Acids Secreted by Lactobacillus spp. Isolated from Urine and Their Antimicrobial Activity against Uropathogenic Proteus mirabilis

The natural microbiota of the urinary tract includes Lactobacillus spp., which secrete molecules with antimicrobial properties and have antagonistic activity against many pathogens. This paper focuses on the antibacterial effect of Lactobacillus strains isolated from urine against clinical strains of Proteus mirabilis isolated from kidney stones and from urine with coexisting urolithiasis. The study involved analyzing the main antimicrobial molecules secreted by Lactobacillus. In order to indicate which agent had the strongest antimicrobial effect, the supernatants were made alkaline and treated with catalase and high temperature. Both treated and untreated supernatants were analyzed for their activity. Exposing uropathogens to all untreated cell-free supernatants of Lactobacillus significantly reduced their growth, and it was established that these properties were related to organic acid secretion by these strains. Using LC–MS/MS and spectrophotometric techniques, lactic, citric, and succinic acids were determined qualitatively and quantitatively. The influence of these acids on the P. mirabilis growth and biofilm formation and their influence on membrane permeability were also investigated. The results indicate that organic acids secreted by Lactobacillus strains have a high antibacterial potential and could be used as novel agents in the treatment of urinary tract infections caused by P. mirabilis.     

离子排斥色谱法同时测定生物质液体燃料发酵液中的有机酸、糖、醇

建立了离子排斥色谱法同时分析生物质燃料乙醇发酵液中糖、酸和醇的方法。使用Bio-Rad Aminex HPX–87H离子排斥色谱柱,以5 mmol/L H2SO4为流动相,柱温为65℃,流量为0.6 m L/min,用示差折光检测器对玉米秸秆发酵液中的纤维二糖、葡萄糖、木糖、阿拉伯糖、甲酸、乙酸、丁酸、乙醇进行定量分析。方法的加标回收率为97.5%~107.4%,相对标准偏差为0.27%~2.19%(n=6),线性相关系数均大于0.999。该方法适用于生物质发酵制乙醇过程中发酵糖、有机酸和乙醇的测定。     

离子交换色谱法对8种有机酸含量的同时测定

建立了淋洗液自动发生梯度淋洗的离子交换色谱法同时测定果汁中乳酸、乙酸、苹果酸、丙二酸、马来酸、草酸、柠檬酸、异柠檬酸8种有机酸的分析方法.样品经处理后用lonPac AS11-HC分离柱和lonPac AG11-HC型保护柱分离,以EG40自动淋洗液发生器生成的0.8～30 mmol/L KOH为淋洗液梯度洗脱,抑制型...     

Behaviors of Organic Ligands and Phosphate during Biochar-Driven Nitrate Adsorption in the Presence of Low-Molecular-Weight Organic Acids

A batch experiment was conducted to examine the behavior of nitrate, organic ligands, and phosphate in the co-presence of biochar and three common low-molecular-weight organic acids (LMWOAs). The results show that citrate, oxalate, and malate ions competed with nitrate ion for the available adsorption sites on the biochar surfaces. The removal rate of LMWOA ligands by the biochar via adsorption grew with increasing solution pH. The adsorbed divalent organic ligands created negatively charged sites to allow binding of cationic metal nitrate complexes. A higher degree of biochar surface protonation does not necessarily enhance nitrate adsorption. More acidic conditions formed under a higher dose of LMWOAs tended to make organic ligands predominantly in monovalent forms and failed to create negatively charged sites to bind cationic metal nitrate complexes. This could adversely affect nitrate removal efficiency in the investigated systems. LMWOAs caused significant release of phosphate from the biochar. The phosphate in the malic acid treatment tended to decrease over time, while the opposite was observed in the citric- and oxalic-acid treatments. This was caused by re-immobilization of phosphate in the former due to the marked increase in solution pH over time.     

淋洗液自动发生-离子色谱法同时测定食品中的21种有机酸

建立了一种利用离子色谱法同时测定样品中奎尼酸、乙酸、丙酮酸、草酰乙酸、甘露酸、乳酸、琥珀酸、苹果酸、酒石酸、草酸、富马酸、抗坏血酸、α-酮戊二酸、肉桂酸、水杨酸、柠檬酸、异柠檬酸、阿魏酸、顺乌头酸、反乌头酸、β-香豆酸等21种有机酸的方法。样品经提取、脱色、过滤后用IonPac AS11分离柱分离,以EG40自动淋洗液发生器生成的5~34 mmol/L KOH为淋洗液洗脱,抑制电导检测器检测。21种有机酸的浓度与其峰面积在一定的范围内呈良好的线性关系,检出限均低于0.188 mg/L,加标回收率为91.5%~101.8%。该法用于多种食物样品中有机酸的测定,结果令人满意。     

Novel Determination of Organic Acids in Diesel and Motor Oil by Ion Chromatography

A robust analytical method is required for the determination of low-molecular weight organic acids, which are potential causes of refinery and internal combustion engine corrosion. The ion chromatographic method developed in this study allows the determination of acetic acid and formic acid in diesel oil mixtures with a motor oil volume fraction of up to 10%. The hydrophobic matrix is automatically removed in-line through a matrix elution step with organic solvent and nonaqueous anion-exchange analyte extraction. Acetic acid and formic acid, as the smallest and most acidic aliphatic naphthenic acids, were determined. Gradient anion-exchange chromatography on high-capacity columns in combination with suppressed conductivity detection allowed their selective and sensitive determination. Typical recovery values were from 82 to 107% for each acid in the matrices evaluated with reproducibility less than 5% for acid fortified samples.