Trace anion determination in concentrated hydrofluoric acid solutions by two-dimensional ion chromatography I. Matrix elimination by ion-exclusion chromatography

Since years, ion exclusion chromatography (ICE) has been the standard method to separate strong acid analyte anions from concentrated weak acid matrices such as hydrofluoric acid (HF). In this work, the commercially available IonPac ICE-AS 1 column was used to separate trace levels of chloride, nitrate, sulfate and phosphate from HF solutions at 20% (w/w). The efficiency of the separation was studied in more detail using techniques such as ion chromatography (IC), inductively coupled plasma optical emission spectrometry (ICP-OES) and ICP-mass spectrometry (ICP-MS). For 20% (w/w) HF solutions and at a water carrier flow-rate of 0.50 ml/min, the cut window was set from 8.5 to 14.5 min. Under these conditions, analyte recoveries of better than 90% were obtained for chloride, nitrate and sulfate, but only about 75% for phosphate. The HF rejection efficiency was better than 99.9%. It was found that the ICP techniques, measuring total element levels and not species, yielded significantly higher recoveries for phosphorus and sulfur compared to IC. Evidence will be given that part of the added phosphorus (approximately 15% for an addition of 10 mg PO4/kg) is present as mono-fluorophosphoric acid (H2FPO3). In the case of sulfate, the difference between IC and ICP-MS could be attributed to an important matrix effect from the residual HF concentration.     

毛细管气相色谱法测定5种中草药中有机氯农药的残留量

建立了怀牛夕等 5种中草药中六六六及滴滴涕异构体含量的气相色谱分析方法。样品以石油醚 +丙酮在索氏提取器中提取 ,提取液以浓硫酸净化。采用SE 30弹性石英毛细管柱分离样品 ,GC ECD检测六六六、滴滴涕农药的残留量。方法的线性范围为 5 .7× 10 - 7～ 2 .8× 10 - 4μg ;最小检测量为 1.3× 10 - 1 4～ 2 .5×10 - 1 2 g ;加样平均回收率为 88.8%～ 99.1% ;RSD为 0 .9%～ 5 .3%。     

Human insulin and desamido human insulin isotherms in ethanol-water reversed phase systems

The multi-component isotherms for human insulin (HI) and desamido human insulin (dHI) over reversed phase packing (C18) and with 29.8% (w/w) ethanol-water as mobile phase have been determined experimentally. The isotherms of HI in ethanol-water differ from those obtained with the more commonly applied methanol-water and acetonitrile-water mobile phase, as described in this paper. The isotherm exhibits anti Langmuirian behavior and can be very well modeled by an anti Langmuir isotherm presented in this paper. The HI and dHI anti Langmuir isotherm are determined as: qHI = (8.4C(HI) + 3C(HI)CdHI)/(1 - 0.05C(HI) - 0.14CdHI + 0.04C(HI)CdHI) and qdHI = (11.4CdHI + 2C(HI)CdHI)/ (1 - 0.05C(HI) - 0.14CdHI + 0.04C(HI)CdHI)     

A column packing for isothermal gas chromatographic analysis of C1−C5 paraffins and monoolefins and dimethyl ether

Summary An analytical GC method was developed which uses a single packed column consisting of three packings in series prepared with the following liquid phases: dimethyl sulfolane, propylene carbonate, and silver nitrate. This system provides satisfactory resolution of mixtures of C₁–C₅ hydrocarbons and dimethyl ether obtained when converting methanol to gasoline. Due to the high capacity of the column it is possible to inject larger sample amounts permitting trace analysis.     

Evaluation of gas chromatography-tandem quadrupole mass spectrometry for the determination of organochlorine pesticides in fats and oils

A gas chromatography-tandem quadrupole mass spectrometry multi-residue method for the analysis of 19 organochlorine pesticides in fats and oils has been developed. Gel permeation chromatography was employed to remove lipid material prior to GC-MS/MS analysis. Average recoveries of the pesticides spiked at 10 and 50 microg kg(-1) into fish oil, pork fat, olive oil and hydrogenated vegetable oil were typically in the range 70-110% with relative standard deviations generally less than 10%. Calculated limits of detection are between 0.1 and 2.0 microg kg(-1) and results obtained for the analysis of proficiency test materials are in good agreement with assigned values. The higher selectivity of the GC-MS/MS compared to electron capture detection and GC-MS in selective ion monitoring mode allowed unambiguous identification and confirmation of all the target pesticides at low microg kg(-1) levels in fats and oils in a single analysis.     

高效液相色谱法测定精对苯二甲酸中微量杂质

建立了高效液相色谱法（HPLC）同时测定精对-苯二甲酸（PTA）中微量杂质4-羧基苯甲醛（4-CBA）、对-甲基苯甲酸（P-TOL）和苯甲酸（C7H6O2）含量的方法。采用的色谱柱为Shim-PackWAX-1柱，流动相为0.1mol/L NH3H2PO4 6%CH3OH，(pH4.5)，检测波长为254nm。PTA中微量杂质4-CBA、P-TOL和C7H6O2的含量分别为0.59-235.20mg/kg、4.52-392.00mg/kg和0.28-24.55mg/kg时线性关系良好，其线性相关系数分别为0.9998、0.9997和0.9999。苯甲酸加样平均回收率99.03％，RSD0.37％。     

白酒中C_9－C_（18）脂肪酸的气相色谱分析

白酒中Ｃ＿９－Ｃ＿（１８）脂肪酸的气相色谱分析周在德，曾永昌（四川大学化学系成都６１００６４）关键词气相色谱法，白酒，Ｃ＿９－Ｃ＿（１８）脂肪酸。白酒中脂肪酸的含量及相互比例关系，极大地影响着白酒的色，香，味，风格￣（［１］［２］）。一般采用的化学分...     

Gas chromatographic trace analysis of underivatized nitrophenols

Summary A method for the gas chromatographic trace analysis of underivatized nitrophenols in ground-water is presented. Using a highly de-activated separation system a satisfactory precision for their quantitative GC analysis could be achieved by avoiding condensation of the solvent and by fast injection of the sample. The reproducibility of the peak areas of eleven nitrophenols in ethylacetate was <5 % RSD. Using a nitrogen-phosphorus detector detection limits were in a range from 10 to 30 pg. Within the concentration range from 0.1 to 10 ng μl⁻¹ the calibrations were linear with correlation coefficients >0.992. The approach described was applied to the analysis of nitrophenols in ground-water near a former ammunition plant, after preconcentration by continuous liquid/liquid extraction with ethylacetate. Using a GC-MS technique and retention times various nitrophenols were identified and then quantified in the μg/L-range by applying NPD.     

高效液相色谱法测定细胞分裂素的方法研究

利用高效液相色谱法测定水稻愈伤组织和微生物发酵产品中的玉米素，二氢玉米素，核糖基玉米素和核糖基二氢玉米素。样品用抽提液抽提，经Ｂｉｏ－Ｒｅｘ７０弱阳离子交换柱和ＸＡＤ－７／Ｓｅｐ－ｐａｋＣ１８复合柱净化和富集后，直接用ＨＰＬＣ分析，方法回收率达９４％～８４％，相对标准偏差小于３．３％。最低检测限达２．０ｎｇ。     

Simultaneous isolation and determination of esculin and rutin in natural materials using SPE and HPLC

Summary Esculin (ESC) and rutin (RUT) have been simultaneously isolated from pharmaceutical natural materials by solid phase extraction (SPE). Determination of both substances was performed by reversed phase high performance liquid chromatography (RPHPLC) with UV detection. Optimization of the separation conditions showed that simultaneous isolation and determination of rutin and esculin from pharmaceutical material was possible. The recovery obtained was not lower than 95±2%.