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    Chinese Journal of Chromatography
    2012, Vol. 30, No. 04
    Online: 28 April 2012

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    Recent advances in capillary scale ion chromatography technology
    YANG Bingcheng*, DIAO Xuefang
    2012, 30 (04):  333-339.  DOI: 10.3724/SP.J.1123.2011.12066
    Abstract ( 1977 )   [Full Text(HTML)] () PDF (179KB) ( 336 )  
    Ion chromatography (IC) has been a well-established technique for the analysis of ionic samples. The aqueous solution used for IC eluent is well suited for bioanalysis in relative to common liquid chromatography. This is especially true for capillary ion chromatography (CIC) due to its advantage of small sample needed. CIC is generally divided into three categories including open tubular, packed and monolithic. In this review, the recent progress of CIC is summarized based on the development of several key components associated with packed column-based system. The development of open tubular ion chromatography is also reviewed.
    Determination of trace anions in atmosphere absorption solution by ion chromatography with the application of online sample neutralization, column concentration and online standard addition
    HE Wei, DING Hui, SHI Chaoou*, YANG Liu, WANG Wenjia
    2012, 30 (04):  340-344.  DOI: 10.3724/SP.J.1123.2011.12068
    Abstract ( 1887 )   [Full Text(HTML)] () PDF (212KB) ( 239 )  
    A novel ion chromatographic method was developed to directly determine trace anion (Cl~, NO~2, NO~3, SO2~4) in atmosphere absorption solution with incorporation of large volume injection, online sample neutralization, column concentration and online standard addition. After comparing the results in different valve switching times and the chromatograms using different online neutralizing columns, the optimum experimental conditions were established. The application of Inguard H online neutralizing column and Carbonate Removal Device (CRD 200) eliminated the matrices OH~ and carbonate. The improvement of the anion detection limit could be achieved by using large volume injection. The results showed that the detection limits of Cl~, NO~2, NO~3 and SO2~4 were 17.5, 171, 34.7, and 42.4 ng/L, respectively. Online standard addition replaced the preparation of trace anion standard solution and avoided the low recovery of NO~2. The method has the characteristics of automatic operation, good repeatability and high efficiency, and can be applied to the detection of ultra trace anions which are hard to be determined in common ion chromatography.
    Determination of trace aromatic amines in waste water using microextraction combined with ion chromatography
    ZHU Yin1, ZHU Yan2, WANG Lili1*
    2012, 30 (04):  345-349.  DOI: 10.3724/SP.J.1123.2011.12075
    Abstract ( 1690 )   [Full Text(HTML)] () PDF (210KB) ( 313 )  
    Liquid-phase microextraction with porous hollow ?bers is a novel pretreatment technology which integretes sampling,extration and concentration into one step. In the past few years, with the development of ion chromatography, it is possible to determine aromatic amines with cation exchange column. In this work, a new method for the determination of trace aromatic amines, incuding o-toluidine and 4-chloroaniline in waste water was developed by hollow fiber membrane extraction with ion chromatography. Chromatographic conditions were optimized. The optimal extraction conditions were as follows: 1-octanol as organic phase with 500g/L NaCl and 0.01 mmol/L NaOH as donor phase, while 0.1 mmol/L HCl as receiving phase, at stirring rate of 430 r/min for 30 min. The linear ranges of o-toluidine and 4-chloroaniline was 0.005–0.1mg/L, with correlation coeffcients larger than 0.999. Detection limits of o-toluidine and 4-chloroaniline were 0.2 μg /L and 0.5 μg /L with RSD at 0.85 % and 3.38 % , respectively. The method has been applied to analyze trace aromatic amines, incuding o-toluidine and 4-chloroaniline in simulated waste water.
    Water Quality Monitoring of Jialing-river in Chongqing Using Advanced Ion Chromatographic System
    Kazuhiko TANAKA1,2, Chao-Hong. SHI1, Nobukazu NAKAGOSHI1
    2012, 30 (04):  350-355.  DOI: 10.3724/SP.J.1123.2011.12044
    Abstract ( 1433 )   [Full Text(HTML)] () PDF (216KB) ( 167 )  
    The water quality monitoring operation to evaluate the water quality of highly polluted river is extremely important task for the river-watershed management/control based on the environmental policy. In this study, the novel, simple and convenient water quality monitoring of Jialing-river in Chongqing, China was developed using an advanced ion chromatography (IC) consisting of ion-exclusion/cation-exchange chromatography (IEC/CEC) with conductivity detection for determining simultaneously common anions such as SO42-, Cl-, and NO3- and the cations such as Na+, NH4+, K+, Mg2+, and Ca2+, the ion-exclusion chromatography (IEC) with visible detection for determining simultaneously the nutrient components such as phosphate and silicate ions, and the IEC with the enhanced conductivity detection using a post column of K+-form cation-exchange resin for determining HCO3--alkalinity as an inorganic-carbon source for biomass synthesis in biological reaction process under the aerobic conditions. . According to the ionic balance theory between the total equivalent concentrations of anions and cations, the water quality evaluation of the Jialing-river waters taking at different sampling sites in Chongqing metropolitan area was carried out using the advanced IC system. As a result, the effectiveness of this novel water quality monitoring methodology using the advanced IC system was demonstrated on the several practical applications to a typical biological sewage treatment plant placed on Jialing-river of Chongqing.
    Ion-exclusion/anion-exchange chromatography on a strongly basic anion-exchange resin in the OH?-form with basic eluent
    Masanobu MORI1*, Takahiro HIRONAGA1, Hideyuki ITABASHI1, Nobutake NAKATANI2, Daisuke KOZAKI3, Kazuhiko TANAKA3
    2012, 30 (04):  356-360.  DOI: 10.3724/SP.J.1123.2011.12047
    Abstract ( 1290 )   [Full Text(HTML)] () PDF (220KB) ( 287 )  
    Ion-exclusion/anion-exchange chromatography (IEC/AEC) on a combination of a strongly basic anion-exchange resin in the OH?-form with basic eluent has been developed. This system is useful for simultaneous separation and determination of ammonium ion (NH4+), nitrite ion (NO2?), and nitrate ion (NO3?) in water sample. The resolution of analyte ions can be manipulated by changing concentration of base in eluent on a polystyrene-divinylbenzene based strongly basic anion-exchange resin column (TSKgel Super IC-Anion). In the elution of 2 mM LiOH, the limits of detection at signal-to-noise of 3 were 4.10 ?M in NH4+, 1.87 ?M in NO2? and 2.83?M in NO3?.
    Enhanced Conductivity Detection of Common Inorganic Anions in Electrostatic Ion Chromatography Using Water Eluent
    Daisuke KOZAKI1, *, Kazuhiko TANAKA1, 2, Nobutake NAKATANI3
    2012, 30 (04):  361-364.  DOI: 10.3724/SP.J.1123.2011.12049
    Abstract ( 1249 )   [Full Text(HTML)] () PDF (162KB) ( 284 )  
    To enhance the conductivity detection sensitivity of the common anions (Na-anions) in the electrostatic ion chromatography (EIC) by elution with water, a conductivity enhancement column packed with a strongly acid cation-exchange resin in the H-form is inserted between the ODS-silica separation column modified with zwitterionic sufactan(CHAPS: 3-{(3-cholamidopropyl)-dimethylammonio}propanesulfonate) column and conductivity detector. Specifically, the Na-anion pairing is converted to H-anions paring after the EIC separation and then detected sensitively by conductivity detector. The effects of conductivity enhancement and suppression in the EIC by the enhanced conductivity detection is characterized for the common strong acid anions such as SO42-, Cl-, NO3-, I- and ClO4- and weak acid anions such as F-, NO2-, HCOO-, CH3COO- and HCO3-. For the conductivity enhancement effect in the EIC, it is found that the conductivity of measured for all strong acid anions (Na-anions) was enhanced according to the theoretical conductivity predicted for H-anions and that of measured for weak acid anions was suppressed depending on their pKa1 of H-anions. For the calibration linearity in the EIC, the strong acid anions were linear (r2 = 0.99–1.00) because the degree of dissociation is almost 1.0 over all the concentration range and that of the weak acid anions were non-linear because the degree of dissociation is decreased by increasing the concentration of the weak acid anions. In conclusion, the EIC by enhanced conductivity detection was recognized to be useful only for the strong acid anions in terms of conductivity detection and calibration linearity.
    Development and Application of Advanced Ion Chromatography for Water Quality Monitoring
    Nobutake Nakatani1,Daisuke Kozaki2,Kazuhiko Tanaka2
    2012, 30 (04):  365-368.  DOI: 10.3724/SP.J.1123.2011.12050
    Abstract ( 1123 )   [Full Text(HTML)] () PDF (162KB) ( 246 )  
    In this study, recent our work on advanced ion chromatographic methods for the simultaneous determination of inorganic ionic species such as common anions (SO42-, Cl- and NO3-) and cations (Na+, NH4+, K+, Mg2+, and Ca2+), nutrients (phosphate and silicate) and hydrogen ion/alkalinity were summarized first. Then, the applications using these methods for monitoring of environmental water quality were also presented. For the determination of common anions and cations with nutrients, the separation was successfully performed by a polymethacrylate-based weakly acidic cation-exchange column of TSKgel Super IC-A/C (Tosoh, 150 mm × 6.0 mm i.d.) and a mixture solution of 100 mM ascorbic acid and 4 mM 18-crown-6 as an acidic eluent with dual detection of conductivity and spectrophotometry. For the determination of hydrogen ion/ acidity, the separation was conducted by TSKgel ODS-100Z column (Tosoh, 150 mm × 4.5 mm i.d.) modified with lithium dodecylsulfate and an eluent of 40 mM LiCl/0.1 mM lithium dodecylsulfate/0.05 mM H2SO4 with conductivity detectoe. The differences of ion concentration between in untreated and treated wastewater showed the variation of ionic species during biological treatment process in a sewage treatment plant. Occurrence and distribution of water-quality conditions were related to the bioavailability and human activity in watershed. From these results, our advanced ion chromatographic methods have contributed significantly for water quality monitoring of environmental waters.
    Analysis of aliphatic carboxylic acids in anaerobic digestion process waters by ion-exclusion chromatography
    Kazuaki ITO1,*, Jun SAKAMOTO1, Kazuya NAGAOKA1, Yohichi TAKAYAMA1, Takashi KANAHORI1, Hiroshi SUNAHARA2, Tsuneo HAYASHI2, Shinji SATO3, Takeshi HIROKAWA4, Kazuhiko TANAKA5,*
    2012, 30 (04):  369-373.  DOI: 10.3724/SP.J.1123.2011.12046
    Abstract ( 1357 )   [Full Text(HTML)] () PDF (190KB) ( 225 )  
    The analysis of seven aliphatic carboxylic acids, formic, acetic, propionic, iso-butyric, n-butyric, iso-valeric and n-valeric acids in anaerobic digestion process waters for biogas production was examined by ion-exclusion chromatography using dilute acidic eluents (benzoic acid, perfluorobutyric acid (PFBA) and sulfuric acid) and non-suppressed conductivity / UV detection. The columns used were a styrene/divinylbenzene-based strongly acidic cation-exchange resin column (TSKgel SCX) and a polymethacrylate-based weakly acidic cation-exchange resin column (TSKgel Super IC-A/C). A good separation was performed on the TSKgel SCX in shorter retention times. For the TSKgel Super IC-A/C, peak shape of the acids was sharp and symmetrical in spite of longer retention times and the mutual separation of the acids was good except for iso- and n-butyric acids. The better separation and good detection was achieved by using the two columns (TSKgel SCX and TSKgel Super IC-A/C connected in series), lower PFBA and sulfuric acid as eluents, and non-suppressed conductivity detection and UV detection at 210 nm, and was applied to anaerobic digestion process waters. The chromatograms with conductivity detection were relatively simple compared to those with UV detection. The use of two columns with different selectivity for aliphatic carboxylic acids and two detection modes was effective for determination and identification of the analytes in anaerobic digestion process waters containing complex matrices.
    Direct determination of nitrites, nitrates and phosphates in seawater using suppressed conductivity ion chromatography with large volume injection and on-line sample preparation techniques
    LIN Hongmei1,2, LIN Qi1,2*, ZHANG Yuanhui1,2, ZHANG Jingjing3, CHEN Liqi1,2*
    2012, 30 (04):  374-377.  DOI: 10.3724/SP.J.1123.2011.12064
    Abstract ( 2149 )   [Full Text(HTML)] () PDF (189KB) ( 404 )  
    Using on-line pre-chlorine and sulfate removal technique, a rapid and direct method was established for the simultaneous determination of nitrite-N, nitrate-N and phosphate-P in seawater by ion chromatography (IC) with suppressed conductivity detection. In this method, an IonPac AG23 column was used as the enrichment column, an IonPac AS23 column with high capacity as the analytical column, and KOH solution as the eluent for gradient elution produced by an eluent generator on-line automatically. The results showed that the determination of the targets was not interfered when a seawater sample diluted 5 to 10 times was directly injected. The method detection limits (MDL) of nitrite-N, nitrate-N and phosphate-P were 0.3, 0.4 and 0.2 μg/L respectively, under the conditions of 500 μL sample volume and 1 mL/min elution rate. The linear ranges of nitrite-N, nitrate-N and phosphate-P were 10~500 μg/L, 14~680 μg/L and 3.4~170 μg/L respectively, and the correlation coefficients (r) were all greater than 0.9990. The average recoveries of the 3 analytes spiked in a sample ranged from 92% to 106% with the relative standard deviations (RSDs, n=6) of 1.2%~7.7%. The whole sample analysis process can be completed in 13 min. The method has the advantage of simple operation, reagent-free and pollution-free, and can meet the quantitative analysis requirements of seawater.
    Determination of heat stable salt anions in alkanolamine desulphurization solution by ion chromatography
    TANG Fei, WANG Yujie, LUO Qin, TANG Meng, CHEN Gengliang*
    2012, 30 (04):  378-383.  DOI: 10.3724/SP.J.1123.2011.12071
    Abstract ( 2116 )   [Full Text(HTML)] () PDF (209KB) ( 289 )  
    To control the potential risk of natural gas purification plants, an ion chromatographic method has been developed to determine the heat stable salts (HSS) in alkanolamine desulphurization solution. Seven HSS anions, including CH3COO~, HCOO~, Cl~, SO2~4, C2O2~4, S2O2~3, SCN~, were determined in a single injection. Before the chromatographic analysis, these industrial samples were pretreated by three steps, i.e. filtration, solid phase extraction and dilution. Using the gradient elution with KOH solution, all of the seven anions have been separated and determined by a conductivity detector. As the calibration results, the linear range of this method was 0.01~0.5 mmol/L for the 7 anions. The limit of detection (LOD, S/N=3) was 0.1 mg/L for each anion. By spiked standard solutions in the samples, the recoveries were in the range of 80.0%~100.3%. The repeatability of this method was evaluated at five different concentrations. The relative standard deviations (RSD, n=10) of the peak areas were in the range of 0.94% to 3.99%. Moreover, the reproducibility of the method was also tested in three different laboratories and it was acceptable with the RSD<5%. The proposed method has been applied to the determination of HSS in eight gas purification plants, three oil refineries and one coal gas plant and to monitor a gas purification plant continuously in 15 days. It’s shown that the accuracy and precision of this method are satisfactory.
    Determination of ionic liquid anions of trifluoroacetate, thiocyanate, tetrafluoroborate and trifluoromethanesulfonate by ion-pair chromatography with direct conductivity detection
    LIU Yuzhen, YU Hong*, ZHANG Renqing
    2012, 30 (04):  384-390.  DOI: 10.3724/SP.J.1123.2011.12074
    Abstract ( 2005 )   [Full Text(HTML)] () PDF (241KB) ( 558 )  
    An ion-pair chromatographic method with direct conductivity detection was established on a reversed-phase silica-based column for the simultaneous determination of ionic liquid anions of trifluoroacetate, thiocyanate, tetrafluoroborate and trifluoromethanesulfonate. The analytes were separated using a mobile phase of ion pair reagent-malic acid-acetonitrile on the Diamonsil C18 column. The effects of mobile phase composition and column temperature on the retention of the anions were investigated. The optimized chromatographic conditions were as follows: 0.15 mmol/L tetrabutylammonium hydroxide-0.099 mmol/L malic acid-20% (v/v) acetonitrile aqueous solution (pH 6.5) as mobile phase, a column temperature of 25 ℃. Under the optimal conditions, the baseline separation of trifluoroacetate, thiocyanate, tetrafluoroborate and trifluoromethanesulfonate was achieved without any interference by other ordinary anions (fluoride, chloride, bromide, nitrate, sulfate). The detection limits (S/N=3) were 0.21, 0.07, 0.36 and 0.12 mg/L for trifluoroacetate, thiocyanate, tetrafluoroborate and trifluoromethanesulfonate, respectively. The method has been applied to the determination of the four anions in ionic liquids. The spiked recoveries of the anions were from 95.0% to 104.6%. The results demonstrate that the convenience, rapidity, sensitivity and accuracy are fit for the requirements of quantitative analysis of trifluoroacetate, thiocyanate, tetrafluoroborate and trifluoromethanesulfonate in ionic liquids.
    Simultaneous determination of phosphorous by-products and inorganic anions in glyphosate mother liquor by ion chromatography with suppressed-conductivity detection
    HU Zhongyang*, YE Mingli, PAN Guangwen, ZHANG Tingting, ZHONG Naifei
    2012, 30 (04):  391-394.  DOI: 10.3724/SP.J.1123.2011.12060
    Abstract ( 2052 )   [Full Text(HTML)] () PDF (149KB) ( 383 )  
    The by-product anion content was an important index for the evaluation of pesticide glyphosate’s productivity technology. A method was developed for the simultaneous determination of glyphosate, phosphorous by-products and other trace impurity anions in the mother liquor of glyphosate procedure by ion chromatography (IC). The sample was diluted with deionized water and filtrated by 0.22 μm nylon filter membrane, and then analyzed by IC directly without anymore pretreatment. The analytical column was Dionex IonPac AS11-HC (250 mm×4 mm) with a guard column IonPac AG11-HC (50 mm×4 mm). Gradient KOH eluent generated by an eluent generation cartridge was used at a flow rate of 1.0 mL/min. The detection was performed by a Dionex suppressed conductivity detector. The quantitative analysis of external standard calibration curves was used. The linear ranges of the method for glyphosate, methyl glyphosate, hexamethylphosphoramide (HMPA), glyphosine, phosphite, phosphate, chloride and sulfate were 0.1~20 mg/L (r=0.9995), 0.1~20 mg/L (r=0.9993), 0.1~50 mg/L (r=0.9999), 0.25~50 mg/L (r=0.9998), 0.05~20 mg/L (r=0.9999), 0.2~50 mg/L (r=0.9985), 0.02~20 mg/L (r=0.9999) and 0.05~50 mg/L (r=0.9980), respectively. The average recoveries were 93.7%~104.0% with the relative standard deviations less than 2.5% (n=7), and the detection limits (S/N=3) were 0.002~0.025 mg/L. The method has been applied to determine the contents of glyphosate, phosphorous by-products and inorganic anions in the mother liquor of glyphosate with satisfactory results.
    Determination of mannose-6-phosphate by high performance ion-exchange Chromatography and electrochemical detector
    PAN Guangwen*, LIU Lüye, YE Mingli, HU Zhongyang
    2012, 30 (04):  395-399. 
    Abstract ( 1995 )   [Full Text(HTML)] () PDF (162KB) ( 322 )  
    A new method was developed for the determination of mannose-6-phosphate (M6P)of intermediate by high performance ion-exclusion chromatography(IC). The sample was dissolved with purified water, filtrated by 0.22 μm nylon filter membrane, and then analyzed by Ion-exchange Chromatography. The analytical column was IonPac AG18 and IonPac AS18 (250 mm × 4 mm), potassium hydroxide was used as the eluent at a flow rate of 1.0 mL/min. The detection was performed with electrochemical detector (amperometric detector and conductive detector in line). The quantitive analysis of external standard calibration curves was used. With amperometric detector the linear range of the method for mannose-6-phosphate were 0.06 — 10.0 mg/L (r=0.9998). The average recoveries were 92% — 104% with RSDs less than 3%. The detection limit was 0.02 mg/L for mannose-6-phosphate. The method is simple, effective, sensitive and selective. It can be used to determine the quality of intermediate for chemosynthetic industry.
    Determination of cations in wines and beverages based on capillary ion chromatography
    ZHANG Tingting*, YE Mingli, HU Zhongyang, PAN Guangwen, LIANG Lina, WU Shuchao
    2012, 30 (04):  400-403. 
    Abstract ( 1969 )   [Full Text(HTML)] () PDF (180KB) ( 248 )  
    A new method for the determination of five cations (sodium, ammonium, potassium, magnesium and calcium) in wines and beverages was developed and validated based on capillary ion chromatography. With a capillary ion exchange column (IonPac CS12A, 250 mm×0.4 mm, 8 μm) and 18 mmol/L methanesulfonic acid (MSA) elution, the five cations can be well separated in 15 min. After suppression with a capillary suppressor (CCES 300), the background was much decreased, and the sensitivities of the cations were greatly improved. For the milky tea, acetonitrile was added into the sample solution to deposit the proteins. With the pretreatment of an OnGuard RP cartridge to remove hydrophobic substances in the sample, the developed method can be applied to the determination of the cations in wines and beverages. The calibration curves of peak area versus concentration gave correlation coefficients more than 0.9997 for these cations. Average recoveries were between 95.2%~103.3%. The method is suitable for the determination of alkali metals and alkaline-earth metals in wines and beverages. The capillary ion chromatography provides analysis with less solvent consumption and better column efficiency, also possesses the advantages of high sensitivity, good selectivity and environmental friendly.
    Ion chromatographic separation of inorganic ions using a combination of HILIC and cation-exchange resin columns
    Kaori ARAI1, Masanobu MORI1*, Takahiro HIRONAGA1, Hideyuki ITABASHI1, Kazuhiko TANAKA2
    2012, 30 (04):  404-408.  DOI: 10.3724/SP.J.1123.2011.12048
    Abstract ( 3173 )   [Full Text(HTML)] () PDF (200KB) ( 255 )  
    A combination of hydrophilic interaction chromatographic (HILIC) column and a weakly acidic cation-exchange resin (WCX) column was used for simultaneous separation of inorganic anions and cations by ion chromatography (IC). HILIC columns employed SeQuant ZIC-HILIC with a sulfobetaine-zwitterion stationary phase (ZIC-HILIC) and Acclaim HILIC-10 with a diol stationary phase (HILIC-10). When the retention behaviors of analyte ions using two different HILIC columns were investigated in acidic elution condition, analyte anions were strongly retained to HILIC-10, compared to ZIC-HILIC. In contrast, retentions of analyte cations to both HILIC columns were much weaker than those of anions. Thus, a WCX column (TSKgel Super IC-A/C) was connected after a HILIC column in series. The multi-column system could give well-resolved separation of ten ions (Na+, NH4+, K+, Mg2+, Ca2+, H2PO4?, Cl?, Br?, NO3? and I?) with elution of 4 mM tartaric acid plus 8 mM 18-crown-6. This system was applied for simultaneous determination of anions and cations in a vegetable juice sample with satisfied results.
    Simultaneous determination of trivalent chromium and hexavalent chromium in plastics by accelerated solvent extraction-ion chromatography
    YU Ruipeng1, HU Zhongyang2, YE Mingli2, CHE Jinshui2*
    2012, 30 (04):  409-413.  DOI: 10.3724/SP.J.1123.2011.12056
    Abstract ( 2096 )   [Full Text(HTML)] () PDF (171KB) ( 531 )  
    A method based on accelerated solvent extraction-ion chromatography (ASE-IC) was developed for the simultaneous determination of trivalent chromium (Cr(III)) and hexavalent chromium (Cr(VI)) in plastic samples. The accelerated solvent extraction was employed as the pretreatment method for the simultaneous extraction of the Cr(III) and Cr(VI) from the samples. Cr(III) and Cr(VI) were derivatized with 2,6-pyridinedicarboxylic acid (PDCA) and 1,5-diphenyl-carbazide (DPC), and detected by an ultraviolet-visible (UV-Vis) detector at UV and visible wavelengths, respectively. The results showed that the limits of detection for Cr(III) and Cr(VI) were 5.0 μg/L and 0.5 μg/L and the good linearities of the calibration curves for them were in the ranges of 50~1000 μg/L (r2=0.9994) and 5.0~100 μg/L (r2=0.9998), respectively. The recoveries were between 90.7% and 101.1% with the relative standard deviations (RSDs) of 1.7%~4.4% for Cr(III) and Cr(VI). The method is sensitive, reproducible and adaptable to the simultaneous determination of Cr(III) and Cr(VI) in the plastic samples.
    Simultaneous determination of alendronate, pamidronate, ibandronate and risedronate using ion chromatography with integrated pulsed amperometric detection
    CHEN Yu1, LIU Yuxiu2, CHEN Zhidong2, CHEN Meilan3*, ZHU Yan4
    2012, 30 (04):  414-418.  DOI: 10.3724/SP.J.1123.2011.12070
    Abstract ( 2202 )   [Full Text(HTML)] () PDF (217KB) ( 305 )  
    A method for the simultaneous determination of alendronate, pamidronate, ibandronate and risedronate using ion chromatography with integrated pulsed amperometric detection (IPAD) has been developed. The electrochemical behavior showed the catalytic currents of these bisphosphonates are based on the oxidation of amines in their structures. Because the bisphosphonates are polar compounds and present as anions under alkaline condition, therefore, they can be separated by anion exchange chromatography. A Dionex AS18 column (250 mm×2 mm) and an AG18 column (50 mm×2 mm) and 24 mmol/L NaOH solution were used for the separation. Multi-step potential waveform parameters were optimized to maximize the signal-to-noise ratio (S/N), which exhibited adsorption/desorption catalytic features at the gold electrode surface in alkaline solution. Utilizing the optimized waveform, the method showed good linearity (r2=0.9972~0.9995), satisfactory repeatability (relative standard deviations (RSDs) of the peak areas in the range of 0.84%~1.37%) and sufficient sensitivity (limits of detection of 0.061~0.18 μg/mL) for the identification of the four bisphosphonates. The recoveries were 80.81%~97.32% with the RSDs of 1.46%~3.02%. It is demonstrated that this method is a rapid and simple one for the determination of the four bisphosphonates in human plasma.
    Determination of glyphosate in heart blood of corpse by ion chromatography
    WANG Yong1, WU Bo1, LIAN Houbin2, SHI Chaoou3*
    2012, 30 (04):  419-422. 
    Abstract ( 1994 )   [Full Text(HTML)] () PDF (140KB) ( 290 )  
    A method for the determination of glyphosate in human blood by ion chromatography was established. The protein in heart blood from a corpse was precipitated with acetonitrile. The large molecules and Cl~in the supernatant were removed by a Dionex OnGuard II RP column and a Dionex OnGuard II Ag column, respectively. The filtrate was separated on an IonPac AS-19 column with KOH solution as eluent produced online by an eluent generator (EG). A suppressor with external water mode and a conductivity detector for the detection were used. The linear range of this method was 10~100 mg/L with a correlation coefficient (r2) of 0.999 9. The limits of detection (LOD, S/N=3) and quantification (LOQ, S/N=10) of glyphosate in blood were 0.12 mg/L and 0.39 mg/L, respectively. The recoveries ranged between 95.2%~109.1% with the relative standard deviations (RSDs, n=5) of 1.2%~3.7%. The glyphosate content in a heart blood sample from a corpse in an actual case was 508 mg/L detected by this method. This method is simple, sensitive, accurate, and can rapidly provided reliable clues and evidences for glyphosate poisoning cases. This method can meet the needs of public security work.
    Preparation of molecularly imprinted polypyrrole/Fe3O4 composite material and its application in recognition of tryptophan enantiomers
    CHEN Zhidong1, SHAN Xueling1, KONG Yong1,2*
    2012, 30 (04):  423-427.  DOI: 10.3724/SP.J.1123.2011.12055
    Abstract ( 2157 )   [Full Text(HTML)] () PDF (203KB) ( 287 )  
    Ferrosoferric oxide (Fe3O4) magnetic material was first synthesized, and then the in-situ chemical polymerization of pyrrole was carried out on the surface of Fe3O4 by using pyrrole and L-tryptophan (L-Trp) as the functional monomer and templates, respectively. As a result, molecularly imprinted polypyrrole/Fe3O4 composite material was obtained. This composite material was separated from the solution because of its magnetic property. Polypyrrole in the composite was overoxidized in 1 mol/L NaOH solution by applying a potential of 1.0 V, and thus L-Trp templates were de-doped from the composite. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and electrochemical methods were employed to characterize the composite. The solution containing L- or D-Trp was pumped through a porous ceramic tube packed with the composite, separately. High performance liquid chromatography (HPLC) was adopted for the detection of L- or D-Trp in the eluate, and the results indicated that the enrichment ability of the composite for L-Trp was almost 2 times of that of D-Trp. Therefore, the electro-magnetic composite material has potential applications as chromatographic stationary phase for chiral recognition.