Quantitative analysis of chemical warfare agent degradation products in reaction masses using capillary electrophoresis

Quantitative methods have been developed for the analysis of chemical warfare agent degradation products in reaction masses using capillary electrophoresis (CE). This is the first report of a systematic validation of a CE-based method for the analysis of chemical warfare agent degradation products in agent neutralization matrixes (reaction masses). After neutralization with monoethanolamine/water, the nerve agent GB (isopropyl methylphosphonofluoridate, Sarin) gives isopropyl methylphosphonic acid (IMPA) and O-isopropyl O'-(2-amino)ethyl methylphosphonate (GB-MEA adduct). The nerve agent GD (pinacolyl methylphosphonofluoridate, Soman), [pinacolyl = 2-(3,3-dimethyl)butyl] produces pinacolyl methylphosphonic acid (PMPA) and O-pinacolyl O'-(2-amino)ethyl methylphosphonate (GD-MEA adduct). The samples were prepared by dilution of the reaction masses with deionized water before analysis by CE/indirect UV detection or CE/conductivity detection. Migration time precision was less than 4.0% RSD for IMPA and 5.0 RSD for PMPA on a day-to-day basis. The detection limit for both IMPA and PMPA is 100 micrograms/L; the quantitation limit for both is 500 micrograms/L. For calibration standards, IMPA and PMPA gave a linear response (R2 = 0.9999) over the range 0.5-100 micrograms/mL. The interday precision RSDs were 1.9, 1.0, and 0.7% for IMPA at 7.5, 37.5 and 75.0 micrograms/mL, respectively. Corresponding values for PMPA (again, RSD) were 2.9, 1.1, and 1.0% at 7.5, 37.5 and 87.5 micrograms/mL, respectively, as before. Analysis accuracy was assessed by spiking actual neutralization samples with IMPA or PMPA. For IMPA, the seven spike levels used ranged from 20 to 220% of the IMPA background level, and the incremental change in the found IMPA level ranged from 86 to 99 % of the true spiking increment (R2 = 0.9987 for the linear regression). For PMPA, the five spike levels ranged from 10 to 150% of the matrix background level, and similarly, the accuracy obtained ranged from 95 to 97% of the true incremental value (R2 = 0.9999 for the linear regression).     

Separation of chiral compounds by capillary electrophoresis

This review presents the different chiral selectors used in capillary electrophoresis (CE) for the separation of enantiomers. The use of charged cyclodextrins, crown ethers, polysaccharides, proteins, natural and synthetic micelles, macrocyclic antibiotics and ergot alkaloids is discussed in detail. Neutral native and derivatized cyclodextrins are not treated because several review articles have already been published on this topic. Recent developments like the application of two chiral selectors in the same background electrolyte are highlighted.     

Determination of the inorganic degradation products sulfate and sulfamate in the antiepileptic drug topiramate by capillary electrophoresis

A preparative-scale ion-exchange chromatographic process is described for the separation of the four major proteins and lactose from sweet dairy whey. Experiments using a commercial anion-exchange resin were carried out to determine the optimum conditions for initially separating the proteins alpha-lactalbumin, beta-lactoglobulin, bovine serum albumin, immunoglobulin G and lactose from a sweet dairy whey mixture. The separation was accomplished with simultaneous step elution changes in salt concentration and pH. It was found that the anion-exchange step was most effective in separating beta-lactoglobulin from the feed mixture. Following the anion-exchange separation, its breakthrough curve was processed using a commercial cation-exchange resin to further recover the valuable immunoglobulin G. The whey output from an east Tennessee cheese manufacturer was used as a feedstream for the preparative scale experiments and as a reference in scaling to an economically optimized production level operation.     

Separation of tetracyclines by high-performance capillary electrophoresis and capillary electrochromatography

Separations of various tetracycline mixtures by high-performance capillary electrophoresis (HPCE) and a new form of electrochromatography (CEC) are compared. The new CEC method involves etching the inner wall of the capillary surface with an appropriate reagent (ammonium dihydrogen fluoride) in order to produce a significant increase in surface area. The etched surface is then modified by a silation/hydrosilation reaction sequence to first produce a hydride intermediate which is then further reacted to attach a C18 moiety. The bare and hydride capillaries are tested under HPCE conditions while the C18 capillary functions in the CEC mode. The effects of pH and the presence of an organic modifier (methanol) are also studied. Detection limits ( < 10 micrograms/ml) are comparable to previous HPLC and HPCE results. Resolutions for mixtures which simulate real analytical problems are equal to or better than those reported for separations on polymeric and diol columns by HPLC and in earlier studies by HPCE and MECC.     

Separation of enantiomers of drugs by capillary electrophoresis. Part 4: hydroxypropyl-gamma-cyclodextrin as chiral solvating agent

In an extended chiral drug screening program, enantioseparation of 86 racemic drugs was tested with hydroxypropyl-gamma-cyclodextrin as chiral solvating agent (CSA). A total of 30 drugs out of 86 could be resolved in this straightforward approach. The number of experiments performed under identical conditions allows a statistical treatment of the data. The enantioseparation of the analytes is correlated with their interaction strength with the CSA. Hence, the concentration of the CSA is a crucial parameter for optimization of the enantioseparation, as shown by a subset of 23 examples.     

Toxicology and pharmacology of the chemical warfare agent sulfur mustard

There have been reports of chemical attacks in which sulfur mustard might have been used (a) on Iranian soldiers and civilians during the Gulf War in 1984 and 1985 and (b) in an Iraqi chemical attack on the Iranian-occupied village of Halbja in 1988, resulting in many civilian casualties. Heavy use of chemical warfare in Afghanistan by the Soviet military is a recent innovation in military tactics that has been highly successful and may ensure further use of chemical agents in future military conflicts and terrorist attacks as a profitable adjunct to conventional military arms. Mustard is a poisonous chemical agent that exerts a local action on the eyes, skin, and respiratory tissue, with subsequent systemic action on the nervous, cardiac, and digestive systems in humans and laboratory animals, causing lacrimation, malaise, anorexia, salivation, respiratory distress, vomiting, hyperexcitability, and cardiac distress. Under extreme circumstances, dependent upon the dose and length of exposure to the agent, necrosis of the skin and mucous membranes of the respiratory system, bronchitis, bronchopneumonia, intestinal lesions, hemoconcentration, leucopenia, convulsions with systemic distress, and death occur. Severe mustard poisoning in humans is associated with systemic injury, which is manifested as headache, epigastric distresses, anorexia, diarrhea, and cachexia and is usually observed at mustard doses of 1000 mg/min/m3 with damage to hematopoietic tissues and progressive leucopenia. Sulfur mustard is a cell poison that causes disruption and impairment of a variety of cellular activities that are dependent upon a very specific integral relationship. These cytotoxic effects are manifested in widespread metabolic disturbances whose variable characteristics are observed in enzymatic deficiencies, vesicant action, abnormal mitotic activity and cell division, bone marrow disruption, disturbances in hematopoietic activity, and systemic poisoning. Indeed, mustard gas readily combines with various components of the cell such as amino acids, amines, and proteins. Although evidence of an association between lung cancer and mustard gas encountered on the battlefields of World War I is at best suggestive if not problematical (Case and Lea, 1955; Beebe, 1960; Norman, 1975), the epidemiological data accumulated from the poison gas factories in Japan (Yamada et al., 1953; Wada et al., 1968; Inada et al., 1978; Shigenobu, 1980; Nishimoto et al., 1983; Hirono et al., 1984; Takuoka et al., 1986), in Germany (Weiss, 1958; Hellmann, 1970a; Weiss and Weiss, 1975; Klehr, 1984) and in England (Manning et al., 1981; Easton et al., 1988) are substantial (International Agency for Research on Cancer, 1975). Unfortunately, attempts to seek confirmatory and substantial evidence in laboratory animals such as mice (Boyland and Horning, 1949; Heston, 1950; Heston, 1953a; McNamara et al., 1975) and rats (Griffin et al., 1951; McNamara et al., 1975; Sasser et al., 1996) have not been consistent. Sulfur mustard has been shown to be mutagenic in a variety of different species using many different laboratory techniques from fruit flies, microorganisms and mammalian cell cultures (Fox and Scott, 1980). Evidence is slowly accumulating from human data (Hellmann, 1970a; Lohs, 1975; Wulf et al., 1985). Evidence for the teratogenicity of mustard has been negative in assessment of fetotoxicity and adverse effects of mustard on the reproductive potential of both human and animal studies. Indeed, investigations of women adversely affected by mustard are minimal because most of the studies have been performed on former men employees of poison gas factories and have been negative or questionable. We have recently emphasized the need to assess the affect of a suspected teratogen on maternal toxicity in laboratory animals before any conclusions can be made.(ABSTRACT TRUNCATED)     

Analysis of trifluoroacetic acid in lyophilized natural products by capillary electrophoresis

A rapid and simple method for the capillary electrophoretic determination of residual trifluoroacetic acid in lyophilized natural products is described. The technique utilizes 2,6-naphthalenedicarboxylic acid as a separation buffer additive providing indirect ultraviolet absorption detection. Using this method, acceptable precision, accuracy, selectivity, range and linearity were achieved.     

Assessment of the quality of dairy products by capillary electrophoresis of milk proteins

This paper presents an overview of existing capillary electrophoretic methods for the study of milk proteins. The main methods of analysis of caseins, whey proteins and peptides are examined with particular attention to their application to the evaluation of the quality of dairy products. Aspects such as the study of protein polymorphism, evaluation of heat treatments, detection of adulteration and assessment of proteolysis are considered in detail.     

Separation of 24 dansylamino acids by capillary electrophoresis with a non-ionic surfactant

The separation of 24 dansylamino acids was investigated by capillary electrophoresis with an additive of micelles of a non-ionic surfactant, Tween 20. Although two pairs of peaks, norvaline and methionine derivatives, and didansyltyrosine and solvent (methanol), did not show good resolution, other dansylamino acids were well separated within 70 min using 100 mM Tween 20 and pH 2.40. The theoretical plate numbers calculated for dansylamino acids were 28,000-111,000 with a 19-cm capillary column.     

Separation of proteolytic enzymes originating from Antarctic krill (Euphausia superba) by capillary electrophoresis

The viscosity-adjustable property of F127 block copolymer PEO99PPO69PEO99, PEO and PPO being poly(ethylene oxide) and poly(propylene oxide), respectively, was found to be useful for the development of automated capillary electrophoresis (CE). The polymer solution can form a gel-like structure with sieving ability and can also serve as a dynamic coating material, thereby effectively suppressing the electroosmotic flow induced by the ionization of the silanol group on the quartz capillary inner wall. When applied to CE as a separation medium, F127 block copolymer can provide the advantages of high separation resolution, easy injection and replacement of the triblock copolymer solution and convenient capillary column treatment. High reproducibility of DNA electrophoretic migration time in CE by replenishing F127 solution in acid-washed capillary tubings can be achieved. The relative standard deviation of the DNA migration time is less than 2%. In the investigation of F127 concentration and temperature effects on the performance of DNA separation in CE, we have found that the DNA electrophoretic migration behavior in the F127 gel-like solution cannot be described by any one of the existing models.     

Analysis of antibiotics by capillary electrophoresis

The broad category of antibiotics encompasses some of the most widely prescribed pharmaceuticals in the world. As is the case with any pharmaceutical, an antibiotic must be characterized in terms of its potency or activity, and the presence and quantity of impurities. Additionally, any residue or metabolite that may be present as a result of its use must be monitored. Many capillary electrophoretic techniques have been utilized in the analysis of antibiotics, addressing the various aspects of their quantitation, profiling, and monitoring. Some of the more recent applications are summarized in this review article.     

Analysis of nucleotides by capillary electrophoresis

Capillary electrophoresis is a useful tool for the analysis of nucleotides. Methods have been optimized for both CZE and MECC modes. A variety of CZE buffers, such as borate, carbonate and phosphate were used successfully. The pH of the buffer changes the charge on the nucleotides. Therefore, the selectivity of the analytes can be controlled by the acidity of the buffer solution. CE separations of nucleotides have been performed at all pH levels, in both CZE and MECC modes. SDS was the most commonly used modifier in MECC separations, but other additives have been added to optimize selectivity. In addition, nucleotides have been quantified in different matrices, including tissue and cell extracts and several DNA and RNA sources. This paper summarizes the methods used for the optimization of nucleotides by CE and includes the most recent techniques to improve selectivity, reproducibility and sensitivity. A summary of CE methods is used in analyses of nucleotides in biological matrices is included.     

Simple sheath flow reactor for post-column fluorescence derivatization in capillary electrophoresis

A system for post-column fluorescence derivatization in capillary electrophoresis is described. The post-column reactor uses a sheath flow detection cell where the reagents, o-phthaldialdehyde and beta-mercaptoethanol, are added to the sheath buffer and mix by diffusion with the analytes effusing from the separation capillary. Reaction progress is monitored and optimized by imaging a large portion of the sheath flow cuvette using an extended UV source and a CCD camera. Significantly, this design provides the ability to switch between the analysis of pre- and post-column derivatized amino acids and peptides easily and without sacrificing system performance. The lack of turbulent flow in this system minimizes post-separation band broadening. The limit of detection for glycine is 9.4 x 10(-8) M (110 amol) with a separation efficiency of 190,000 theoretical plates, without stacking. The performance of the system for a series of amino acids was evaluated using post-column and pre-capillary derivatization.     

Separation and quantitation of monoclonal antibodies in cell growth medium using capillary zone electrophoresis

IgG1 is separated from its impurities in cell growth medium under simple CZE conditions without specific sample pretreatment. Linearity, limit of quantitation, limit of detection, precision and accuracy for the method are demonstrated. The quantitation for IgG1 in the cell growth medium is obtained by generating a calibration curve and by using standard additions. This CE method can offer a good alternative to conventional HPLC methods. Attempts are also made to separate the heterogeneous species in monoclonal antibodies using both CZE and MECC.     

Characterization of DNA standards by capillary electrophoresis

We have used capillary electrophoresis to evaluate commercial DNA size standards and have found that it can provide an efficient assessment of size. However, the accuracy of the determination is adversely affected by anomalous migration times due to specific interactions of the DNA with the gel matrix as well as conformational differences in the DNA due to sequence heterogeneity. These anomalous migration times are strongly dependent on the choice of gel matrix. For example, the anomalous migration times that are observed in a 1 kilobase standard DNA ladder can be minimized using nongel hydroxyethylcellulose. In addition, the peak resolution can be increased and the anomalous migration can be reduced by the addition of the intercalating dye, ethidium bromide. However, in the case of the D1S80 allelic ladder, some of the DNA fragments possess nucleotide sequences which do not interact equivalently with the dye and produce irregular migration times. These measurements yield preliminary information useful in evaluating DNA size standards which may be used for a wide range of DNA diagnostic applications.     

Detection of 2'-deoxyoxanosine by capillary electrophoresis

We have investigated capillary electrophoresis separation of oxanine (Oxa), a base moiety of 2'-deoxyoxanosine (Figure 1), from various bases. Oxa was not well separated from the others by micelle electrokinetic chromatography which is a general method for separating of the bases. On the other hand, capillary zone electrophoresis showed much improved separation when used pH 12 where the six-membered ring of Oxa is opened.     

Analysis of the antidiabetic drug acarbose by capillary electrophoresis

This study describes the derivatization of the pseudooligosaccharide acarbose and its main metabolite, component 2, with 7-aminonaphthalene-1,3-disulfonic acid (ANDS) in human urine. Their efficient separation was possible by means of capillary zone electrophoresis, using a capillary tube of fused-silica containing 100 mM triethylammonium phosphate buffer, pH 1.5. On column laser-induced fluorescence allowed the detection of the pseudooligosaccharides in human urine in the nanomolar range. With this method, acarbose and component 2 were quantified in human urine after application of 300 mg of acarbose.     

Surface charge reversal for inorganic anion determination in capillary electrophoresis with an ion-selective microelectrode as detector

The effect of surface charge reversal of a fused-silica capillary was investigated for the conditions used in the determination of inorganic anions with potentiometric detection. A 25-micron-i.d. capillary was coated with permanently bonded polyacrylamide incorporating a quaternary amine, and a sodium sulfate solution was employed as electrolyte. As expected, it was found that the analysis time is reduced in comparison with an uncoated column of the same length. However, the effect is much less pronounced than that for the common chromate buffer. Since the reduction in analysis time also causes a loss of resolution, the effect is very close to that obtained simply by using a shorter capillary; therefore, coating was not found to be of benefit here. This is in contrast to results reported for the conditions usually employed for the indirect photometric detection of anions.     

Replaceable polymers in DNA sequencing by capillary electrophoresis

Much progress has been made in the development of replaceable sieving polymers and capillary coatings for high-performance DNA sequencing by capillary electrophoresis. Several studies of parameters that affect resolution, read length and reproducibility have begun to reveal the physical mechanisms acting on single-stranded DNA during electrophoresis through semidilute polymer solutions. Recently developed electro-osmosis-inhibiting matrix polymers have simplified the process of coating capillaries, facilitating the automation of high-throughput parallel systems for large-scale sequencing.     

Chiral separations by capillary electrophoresis in process chemistry

BACKGROUND: Conducting research in clinical settings can be problematic for many nurses in practice due to lack of experience and support. METHOD: Research collaboration between clinical nurse specialists and staff nurses in clinical settings can promote development of their research process skills. RESULTS: Strategies identified can be applied by clinical nurse specialists involved in continuing education and staff development in clinical practice through further research development. CONCLUSION: Collaboration among clinical nurse specialists and staff nurses provides a unique and strong link that transcends degrees and roles to make substantial contributions to professional nursing practice.