CE methods have been developed for the analysis of organic and peroxide-based explosives. These methods have been developed for deployment on portable, in-field instrumentation for rapid screening. Both classes of compounds are neutral and were separated using micellar electrokinetic chromatography (MEKC). The effects of sample composition, separation temperature, and background electrolyte composition were investigated. The optimised separation conditions (25 mM sodium tetraborate, 75 mM sodium dodecyl sulfate at 25°C, detection at 200 nm) were applied to the separation of 25 organic explosives in 17 min, with very high efficiency (typically greater than 300,000 plates m(-1)) and high sensitivity (LOD typically less than 0.5 mg L(-1); around 1-1.5 μM). A MEKC method was also developed for peroxide-based explosives (10 mM sodium tetraborate, 100 mM sodium dodecyl sulfate at 25°C, detection at 200 nm). UV detection provided LODs between 5.5 and 45.0 mg L(-1) (or 31.2-304 μM), which is comparable to results achieved using liquid chromatography. Importantly, no sample pre-treatment or post-column reaction was necessary and the peroxide-based explosives were not decomposed to hydrogen peroxide. Both MEKC methods have been applied to pre-blast analysis and for the detection of post-blast residues recovered from controlled, small scale detonations of organic and peroxide-based explosive devices.

ABSTRACTBackgroundIn Australia, iron polymaltose (IPM) is the most commonly used parenteral iron therapy for iron deficiency anaemia. Intravenous IPM is prepared by diluting IPM injection with 0.9% sodium chloride. The stability of diluted IPM is not known beyond 24 hours. Therefore, diluted IPM must be prepared on a daily basis, resulting in substantial limitations and problems.AimTo determine the stability of diluted IPM in polyvinyl chloride (PVC) infusion bags at different storage conditions for up to 28 days.MethodIPM 2 mg/mL samples were prepared in 0.9% sodium chloride 500 mL PVC infusion bags. Infusion bags were kept in light protective bags or exposed to artificial light and stored at either 4 °C or 25 °C for up to 28 days. Aliquots were withdrawn immediately after preparation (Day 0) or after Days 1, 2, 3, 6, 7, 14, 21 and 28. Samples were analysed by high‐performance size‐exclusion chromatography to measure the changes in concentration or molecular weight profile of IPM before and after storage. Samples were also investigated for particle size distribution by dynamic light scattering and for the free iron content by ion chromatography.ResultsDiluted IPM remained physicochemically stable (with or without light protection) at room temperature or in the refrigerator for at least 28 days.ConclusionAseptically prepared IPM 2 mg/mL intravenous solution in 0.9% sodium chloride PVC infusion bags was stable for 28 days at room temperature or in a refrigerator.

A novel capillary electrophoresis (CE) approach has been developed for the simultaneous rapid separation and identification of common environmental inorganic anions and cations from a single sample injection. The method utilised a sequential injection-capillary electrophoresis instrument (SI-CE) with capacitively-coupled contactless conductivity detection ((CD)-D-4) constructed in-house from commercial-off-the-shelf components. Oppositely charged analytes from a single sample plug were simultaneously injected electrokinetically onto two separate capillaries for independent separation and detection. Injection was automated and may occur from a syringe or be directly coupled to an external source in a continuous manner. Software control enabled high sample throughput (17 runs per hour for the target analyte set) and the inclusion of an isolation valve allowed the separation capillaries to be flushed, increasing throughput by removing slow migrating species as well as improving repeatability. Various environmental and industrial samples (subjected only to filtering) were analysed in the laboratory with a 3 min analysis time which allowed the separation of 23 inorganic and small organic anions and cations. Finally, the system was applied to an extended automated analysis of Hobart Southern Water tap water for a period of 48 h. The overall repeatability of the migration times of a 14 analyte standard sample was less than 0.74% under laboratory conditions. LODs ranged from 5 to 61 mu g L-1. The combination of automation, high confidence of peak identification, and low limits of detection make this a useful system for the simultaneous identification of a range of common inorganic anions and cations for discrete or continuous monitoring applications. (C) 2013 Elsevier B.V. All rights reserved.

It is well known that enoxaparin, a widely used anticoagulant and low-molecular-weight heparin containing a large number of oligosaccharides, possesses anti-inflammatory activity. Whilst enoxaparin has shown promising results in various inflammatory disorders, some of its oligosaccharides have anti-inflammatory properties and others increase the risk of bleeding due to their anticoagulant effects. The aim of this study was to develop an effective ion exchange chromatographic (IC) technique which allows the separation, isolation and, consequently, the identification of different oligosaccharides of enoxaparin with or without anticoagulant activity. The developed method utilises a semi-preparative CarboPac PA100 (9 × 250 mm) ion exchange column with sodium chloride gradient elution and UV detection at 232 nm. The method successfully resolved enoxaparin into more than 30 different peaks. IC-derived oligosaccharides with high, moderate, low or no anticoagulant activity were identified using an anti-factor Xa assay. The anti-inflammatory activity of selected oligosaccharides was investigated using the Griess assay. Using this technique, the oligosaccharides of enoxaparin with low or no anticoagulant activity, whilst exhibiting significant anti-inflammatory activity, could be fractionated. This technique can provide a platform to identify the oligosaccharides which are devoid of significant anticoagulant activity and are responsible for the therapeutic effects of enoxaparin that have been observed in various inflammatory conditions.

In forensic science, the analysis of inorganic ions in postexplosive residues is important for the identification of the explosives. In terrorist attacks, so-called home-made or improvised explosives are often used, and the identification of the explosives provides a good indication of the suspects. In previous work, we have developed methods for complementary portable and field-deployable analysis of postexplosive residues by capillary electrophoresis and ion chromatography. In this paper, the translation of these methods to the Lab on a Chip format will be discussed.

CE has been available as a tool for almost 20 years, but it is only in the past several years that it has been implemented widely. This has been the result of some significant advances in the technique. These fall in the areas of indirect photometric detection (through the use of dyes as probes and LEDs as light sources), the introduction and establishment of capacitively-coupled contactless conductivity detection ((CD)-D-4) as a routine, sensitive and commercially available detection method, and in software capable of simulation of separations and the selection of optimal composition of the BGE. These developments are reviewed and their impact illustrated by reference to a case study involving the rapid separation and sensitive detection of 15 anions and 12 cations on a portable CE instrument. It is shown that (CD)-D-4 provides considerably superior detection sensitivity (by a factor of about 8 in comparison with optimised indirect photometry).

In the present review, reader can be informed of the major developments which have appeared, largely in the past 5 years, and which have resulted in highly significant progress towards overcoming the limitations of CE applied to inorganic analysis.

Polymeric ion-exchange monoliths typically exhibit low capacities due to the limited surface area on the globules of the monoliths. The ion-exchange binding of protonated weakly basic analytes on deprotonated carboxylate sites on methacrylate polymer monoliths has been increased by templating the monoliths with silica nanoparticles. The templating method is achieved by adding the nanoparticles as a suspension to the polymerisation mixture. After polymerisation, the nanoparticles are removed by washing the monolith with strong base. Monolithic columns prepared using this procedure have exhibited a 33-fold increase in ion-exchange capacity when compared to untemplated monoliths prepared and treated under similar conditions. The templating procedure does not alter the macroporous properties of the polymer monolith, confirmed through scanning electron microscopy and BET surface area analysis, but provides increased capacity predominantly through the re-orientation of more carboxylic acid groups. The resulting increase in ion-exchange capacity has proven to be useful for the preconcentration and separation of neurotransmitters by in-line solid-phase extraction-capillary electrophoresis. The increased capacity of the templated monolith allowed the injection time to be increased 10 times over that of an untemplated monolith, allowing 10 times more sample to be injected with the efficiencies and recoveries remaining unaffected. The enhancement in sensitivity for the test mixture of neurotransmitter (dopamine, norepinephrine and metanephrine) ranged 1500-1900 compared to a normal hydrodynamic injection in capillary electrophoresis. Efficiencies obtained for the neurotransmitters were 100000-260000 plates, typical of those obtained in capillary zone electrophoresis. The applicability of the increased capacity silica nano-templated polymer monolith was demonstrated by analysing trace levels of caffeine in biological, food and environmental samples.

A two-dimensional ion chromatography (2D-IC) approach has been developed which provides greater resolution of complex samples than is possible currently using a single column. Two columns containing different stationary phases are connected via a tee-piece, which enables an additional eluent flow and independent control of eluent concentration on each column. The resultant mixed eluent flow at the tee-piece can be varied to produce a different eluent concentration on the second column. This allows analytes strongly retained on the first column to be separated rapidly on the second column, whilst maintaining a highly efficient, well resolved separation of analytes retained weakly on the first column. A group of 18 inorganic anions has been separated to demonstrate the utility of this approach and the proposed 2D-IC method provided separation of this mixture with resolution of all analytes greater than 1.3. Careful optimisation of the eluent profiles on both columns resulted in run times of less than 28 min, including re-equilibration. Separations were performed using isocratic or gradient elution on the first column, with an isocratic separation being used on the second column. Switching of the analytes onto the second column was performed using a gradient pulse of concentrated eluent to quickly elute strongly retained analytes from the first column onto the second column. The separations were highly repeatable (RSD of 0.01-0.12% for retention times and 0.08-2.9% for peak areas) and efficient (typically 8000-260,000 plates). Detection limits were 3-80 ppb.

Analysis of post-blast explosive residues, using analytical methods such as ion chromatography and capillary electrophoresis, has become an essential tool in counterterrorism initiatives.

Novel CE methods have been developed on portable instrumentation adapted to accommodate a capacitively coupled contactless conductivity detector for the separation and sensitive detection of inorganic anions and cations in post-blast explosive residues from homemade inorganic explosive devices. The methods presented combine sensitivity and speed of analysis for the wide range of inorganic ions used in this study. Separate methods were employed for the separation of anions and cations. The anion separation method utilised a low conductivity 70 mM Tris/70 mM CHES aqueous electrolyte (pH 8.6) with a 90 cm capillary coated with hexadimethrine bromide to reverse the EOF. Fifteen anions could be baseline separated in 7 min with detection limits in the range 27-240 mu g/L. A selection of ten anions deemed most important in this application could be separated in 45 s on a shorter capillary (30.6 cm) using the same electrolyte. The cation separation method was performed on a 73 cm. length of fused-silica capillary using an electrolyte system composed of 10 mM histidine and 50 mM acetic acid, at pH 4.2. The addition of the complexants, 1 mM hydroxyisobutyric acid and 0.7 mM 18-crown-6 ether, enhanced selectivity and allowed the separation of eleven inorganic cations in under 7 min with detection limits in the range 31-240 mu g/L. The developed methods were successfully field tested on post-blast residues obtained from the controlled detonation of homemade explosive devices. Results were verified using ion chromatographic analyses of the same samples.

Anions and cations of interest for the post-blast identification of homemade inorganic explosives were separated and detected by ion chromatographic (IC) methods. The ionic analytes used for identification of explosives in this study comprised 18 anions (acetate, benzoate, bromate, carbonate, chlorate, chloride, chlorite, chromate, cyanate, fluoride, formate, nitrate, nitrite, perchlorate, phosphate, sulfate, thiocyanate and thiosulfate) and 12 cations (ammonium, barium(II), calcium(II), chromium(III), ethylammonium, magnesium(II), manganese(II), methylammonium, potassium(I), sodium(I), strontium(II), and zinc(II)). Two IC separations are presented, using suppressed IC on a Dionex AS20 column with potassium hydroxide as eluent for anions, and non-suppressed IC for cations using a Dionex SCS 1 column with oxalic acid/acetonitrile as eluent. Conductivity detection was used in both cases. Detection limits for anions were in the range 2–27.4 ppb, and for cations were in the range 13–115 ppb. These methods allowed the explosive residue ions to be identified and separated from background ions likely to be present in the environment. Linearity (over a calibration range of 0.05–50 ppm) was evaluated for both methods, with r2 values ranging from 0.9889 to 1.000. Reproducibility over 10 consecutive injections of a 5 ppm standard ranged from 0.01 to 0.22% relative standard deviation (RSD) for retention time and 0.29 to 2.16%RSD for peak area. The anion and cation separations were performed simultaneously by using two Dionex ICS-2000 chromatographs served by a single autoinjector. The efficacy of the developed methods was demonstrated by analysis of residue samples taken from witness plates and soils collected following the controlled detonation of a series of different inorganic homemade explosives. The results obtained were also confirmed by parallel analysis of the same samples by capillary electrophoresis (CE) with excellent agreement being obtained.

A method based on indirect photometric detection (IPD) in CE employing a blue LED (473 nm) as a light source and the highly absorbing (478 nm) anionic dye, Orange G, as the probe ion was developed for the sensitive analysis of inorganic and organic anions. The use of nonaqueous solvents was examined as a simple way to reduce the adsorption of the dye onto the capillary wall and to thereby improve the baseline stability. The benefits of this approach were confirmed by experiments using BGEs in methanol (MeOH) and DMSO in which superior baselines were obtained relative to those achieved using aqueous electrolyte systems. A range of commercial LEDs was tested to improve the detection performance, with a difference of 25% in sensitivity being observed between the best and worst performing LED. The final system (4 mM Orange G, 0.05% w/v hydroxypropylcellulose (HPC), 20 mM triethanolamine (TEA) in pure MeOH) exhibited stable baselines and very low LODs (0.10-0.18 mu M) for a test mixture comprising nine inorganic and organic anions. These values represent a two- to six-fold improvement over previous studies and the proposed method provides the most sensitive IPD method for the determination of anions using CE published to date. RSDs for ten replicates were in the ranges of 0.42-0.62% for migration time, 1.41-3.46% for peak area and 3.20-5.78% for peak height.

in this work, a new generation UV-transparent polymer, fluorinated ethylenepropylene copolymer (FEP) exhibiting a low degree of crystallinity, extruded in dimensions similar to the most commonly used CE capillaries of similar to 80 mu m id and about 360 mu m od was investigated for its use as a CE capillary. FEP is transparent down to the low-UV region, and as fluorinated polymers in general are good electrical insulators and exhibit reasonable heat conductivity, it has considerable potential as a material for electrodriven analysis in capillary or microchip formats. The FEP capillary has been characterised with regard to some important aspects for its use as a CE capillary, including its profile of EOF versus pH, as well as procedures for manipulating EOF by coating the inner capillary wall with various semipermanent and dynamic layers. The FEP capillaries were tested and compared with fusedsilica capillary for the separation of inorganic and small organic ions using conditions involving direct and indirect detection in the low-UV region. Finally, advantages of the use of the FEP capillary for simultaneous detection of a mixture containing nine inorganic cations and anions using indirect photometric detection with a movable light-emitting diode (LED) detector and a novel electrolyte are demonstrated.

A polymer monolith bearing weak cation-exchange functionality was prepared for the purpose of demonstrating pH-selective extraction and elution in in-line solid-phase extraction-capillary electrophoresis (SPE-CE) utilising a model set of cationic analytes, namely imidazole, lutidine and 3-phenylpropanamine. Optimization of the electrolyte conditions for efficient elution of the adsorbed analytes using a moving pH boundary required that the capillary and monolith be filled with 44 mM sodium acetate at high pH (pH 6) and a low pH electrolyte of 3 mM sodium acetate pH 3 was placed in the electrolyte vials. This combination allowed the adsorbed analytes to be simultaneously eluted and focused into narrow bands, with peak widths of the eluted analytes having a baseline width of 1.2 s immediately after the monolith. Using these optimum elution conditions, the versatility of the SPE-CE approach was demonstrated by removing unwanted adsorbed components after extraction with a wash at a different pH and also by selecting a pH at which only some of the model weak bases were ionised. The analytical performance of the approach was evaluated and the relative standard deviation for peak heights, peak area and migration times were in the ranges of 1.4-5.3, 1.2-3.3 and 0.4-1.2% respectively. Analytes exhibited linear calibrations with r(2) values ranging from 0.996 to 0.999 over two orders of magnitude. Analyte pre-concentration provided excellent sensitivity, and limits of detection for the analyte used in this study were in the range 8.0-30 ng ml(-1), which was an enhancement of 63 when compared to normal hydrodynamic injection occupying 1.3% of the capillary of these bases in water.

A commercial portable capillary electrophoresis (CE) instrument has been used to separate inorganic anions and cations found in postblast residues from improvised explosive devices (IEDs) of the type used frequently in terrorism attacks. The purpose of this analysis was to identify the type of explosive used. The CE instrument was modified for use with an in-house miniaturized light-emitting diode (LED) detector to enable sensitive indirect photometric detection to be employed for the detection of 15 anions (acetate, benzoate, carbonate, chlorate, chloride, chlorite, cyanate, fluoride, nitrate, nitrite, perchlorate, phosphate, sulfate, thiocyanate, thiosulfate) and 12 cations (ammonium, monomethylammonium, ethylammonium, potassium, sodium, barium, strontium, magnesium, manganese, calcium, zinc, lead) as the target analytes. These ions are known to be present in postblast residues from inorganic IEDs constructed from ammonium nitrate/fuel oil mixtures, black powder, and chlorate/perchlorate/sugar mixtures. For the analysis of cations, a blue LED (470 nm) was used in conjunction with the highly absorbing cationic dye, chrysoidine (absorption maximum at 453 nm). A nonaqueous background electrolyte comprising 10 mM chrysoidine in methanol was found to give greatly improved baseline stability in comparison to aqueous electrolytes due to the increased solubility of chrysoidine and its decreased adsorption onto the capillary wall. Glacial acetic acid (0.7% v/v) was added to ensure chrysoidine was protonated and to enhance separation selectivity by means of complexation with transition metal ions. The 12 target cations were separated in less than 9.5 min with detection limits of 0.11-2.30 mg/L (calculated at a signal-to-noise ratio of 3). The anions separation system utilized a UV LED (370 nm) in conjunction with an aqueous chromate electrolyte (absorption maximum at 371 nm) consisting of 10 mM chromium(VI) oxide and 10 mM sodium chromate, buffered with 40 mM tris(hydroxymethyl)aminomethane at pH 8.05. All 15 target anions were baseline separated in less than 9 min with limits of detection ranging from 0.24 to 1.15 mg/L (calculated at a signal-to-noise ratio of 3). Use of the portable instrumentation in the field was demonstrated by analyzing postblast residues in a mobile laboratory immediately after detonation of the explosive devices. Profiling the ionic composition of the inorganic IEDs allowed identification of the chemicals used in their construction.

p-Nitroaniline was explored as a derivatising reagent for UV absorbance detection of carbohydrates after separation by CE. This derivatising agent has three advantages: first, it has excellent water solubility; second, it has high molar absorptivity; and third, it is possible to obtain sensitive detection using a UV or blue light-emitting diode (LED) as the light source. The labelling reaction took less than 30 min to complete with high reaction yield. The separation process was modelled and optimised using an artificial neural network. Nine carbohydrates were separated by a CE system within 16 min using a 0.17 M boric acid buffer at pH 9.7. On-column LED detection at 406 nm allowed the detection of carbohydrates with good detection limits (< 1.1 mu M or 8.8 fmol) and reproducible quantification in the concentration range of 2.6-200 mu M This method was applied successfully to the determination of component carbohydrates in some food samples.

In the first part of this two-part series, the guest authors explained the principles and approaches to indirect detection and stressed the importance of buffering for method ruggedness. This second part outlines the dl.f.ferent ways electrolytes can be buffered while maintaining compatibility with indirect detection and gives rules and practical guidelines for method development. The authors also discuss some instrumental aspects of indirect photometric detection that affect the method performance.

This review focuses on the indirect photometric detection of anions and cations by capillary electrophoresis. Special emphasis has been placed on the sensitivity of the technique and approaches taken to enhance detection limits. Theoretical considerations and requirements have been discussed, including buffering, detection sensitivity, separation of cations, and detector linearity. A series of tables detailing highly absorbing probes and the conditions of their use for indirect photometric detection are included.