Detection of azide in forensic samples by capillary electrophoresis

Azide salts are highly toxic compounds that have been difficult to detect in forensic samples. Here, anion analysis by capillary electrophoresis with indirect spectrophotometric detection was applied to detect azide in forensic specimens from two suicide victims. Gastric specimens from the victims were shown to have high azide concentrations; azide represented one of the major anionic components and no corresponding component occurred in normal gastric juice. Samples of blood and bile had low concentrations of azide near the limits of detection. The method described for azide analysis used simple steps for sample preparation and analysis time was less than 10 min per sample. It offers a simple and reliable method for detecting azide in biological fluids.     

Analysis of nitrite in adulterated urine samples by capillary electrophoresis

A simple method for analyzing nitrite in urine has been developed to confirm and quantify the amount of nitrite in potentially adulterated urine samples. The method involved separation of nitrite by capillary electrophoresis and direct UV detection at 214 nm. Separation was performed using a bare fused silica capillary and a 25 mM phosphate run buffer at a pH of 7.5. Sample preparation consisted of diluting the urine samples 1:20 with run buffer and internal standard, and centrifuging for 5 min at 2500 rpm. The sample was hydrodynamically injected, then separated using -25 kV with the column maintained at 35 degrees C. The method had upper and lower limits of linearity of 1500 and 80 microg/mL nitrite, respectively, and a limit of detection of 20 microg/mL. The method was evaluated using the National Committee for Clinical Laboratory Standards (NCCLS) protocol (Document EP10-A2), and validated using controls, standards, and authentic urine samples. Ten anions, ClO-, CrO4(-2), NO3-, HCO3-, I-, CH3COO-, F-, SO4-, S2O8(-2), and Cl-, were tested for potential interference with the assay. Interferences with quantitation were noted for only CrO4(-2) and S2O8(-2). High concentrations of Cl- interfered with the chromatography. The method had acceptable accuracy, precision, and specificity.     

Validation of STR typing by capillary electrophoresis

With the use of capillary electrophoresis (CE), high-resolution electrophoretic separation of short tandem repeat (STR) loci can be achieved in a semiautomated fashion. Laser-induced detection of fluorescently labeled PCR products and multicolor analysis enable the rapid generation of multilocus DNA profiles. In this study, conditions for typing PCR-amplified STR loci by capillary electrophoresis were investigated using the ABI Prism 310 Genetic Analyzer (Applied Biosystems). An internal size standard was used with each run to effectively normalize mobility differences among injections. Alleles were designated by comparison to allelic ladders that were run with each sample set. Multiple runs of allelic ladders and of amplified samples demonstrate that allele sizes were reproducible, with standard deviations typically less than 0.12 bases for fragments up to 317 bases in length (largest allele analyzed) separated in a 47 cm capillary. Therefore, 99.7% of all alleles that are the same length should fall within the measurement error window of +/- 0.36 bases. Microvariants of the tetranucleotide repeats were also accurately typed by the analytical software. Alleles differing in size by one base could be resolved in two-donor DNA mixtures in which the minor component comprised > or = 5% of the total DNA. Furthermore, the quantitative data format (i.e., peak amplitude) can in some instances assist in determining individual STR profiles in mixed samples. DNA samples from previously typed cases (typed for RFLP, AmpliType PM+DQA1, and/or D1S80) were amplified using AmpFlSTR Profiler Plus and COfiler and were evaluated using the ABI Prism 310. Most samples yielded typable results. Compared with previously determined results for other loci, there were no discrepancies as to the inclusion or exclusion of suspects or victims. CE thus provides efficient separation, resolution, sensitivity and precision, and the analytical software provides reliable genotyping of STR loci. The analytical conditions described are suitable for typing samples such as reference and evidentiary samples from forensic casework.     

摇头丸中甲基安非他明和咖啡因含量的检验

目的建立了用毛细管电泳分离和测定摇头丸中的甲基安非他明和咖啡因的方法。方法观察缓冲液的种类以及缓冲液的pH值对分离的影响。结果在10～800mg/L的范围内,用Na2HPO4-Na2B4O7和NaH2PO4-Na2HPO4缓冲液,在pH7.0～9.5时,两种药物成分均有较好的线性(r>0.99),三种摇头丸中的甲基安非他明和咖啡因的含量随浓度的增加其回收率增加。结论该分析方法速度快,重现性好,检测结果准确。     

Reliability of SE33 typing by capillary electrophoresis

A ladder of 24 ACTBP2 (SE33) alleles was separated 175 times by denaturing capillary electrophoresis on an ABI Prism 310 Genetic Analyzer using polymer POP-4. The mean standard deviation of fragment size determination was 0.083 bp. Fragments in the whole allelic range of ACTBP2 could be typed with high precision and reproducibility if adjacent fragments differed by at least two nucleotides. The capacity of resolving 1 bp differences was tested by repeatedly running a ACTBP2*14.2/14.3/31.2/31.3 allelic mixture. The 14.2/14.3 fragment pair could be separated in 98%, the 31.2/31.3 fragment pair only in 65% of all runs. Reliable separation of this difficult fragment mixture could exclusively achieved by using POP-6.     

毛细管电泳技术分析炸药残留物中无机离子

目的　建立炸药残留物中无机离子的毛细管电泳检测方法。方法　运用缓冲溶液使无机离子在毛细管电泳中达到分离 ,采用紫外间接检测法分析。结果　该方法可从爆炸残留物中准确检测出无机阴离子 (Cl- 、SO2 - 4、NO- 2 、NO- 3、ClO- 3和ClO- 4离子 )和无机阳离子 (NH 4、K 、Na 和Mg2 离子 )。结论　操作方法简便快捷 ,检材用量少 ,检测极限可达ng/ml级 ,分析结果满意     

A comparison of smokeless powders and mixtures by capillary zone electrophoresis

The analysis of inorganic ions present in smokeless and muzzleloading powders has been performed using capillary zone electrophoresis (CZE). Previous publications have examined inorganic low explosives using CZE, but have not looked at the ion profiles from smokeless powders. In this report, seven commercially available smokeless powders were analyzed as unburned powder and burned residue. The results demonstrate that ionic profiles can be used to characterize smokeless powders. Our analysis also included a smokeless powder/ Pyrodex combination to determine if smokeless powder ions are distinguishable in a mixture; however, the high concentration of ions present in Pyrodex RS prevented its detection. In addition, five different smokeless powder samples as well as Pyrodex RS were collected for analysis subsequent to deflagration in fifteen plastic pipe bombs. The relative ion concentrations between these powders can be used to illustrate the differences between open burning and pipe bomb deflagration.     

Comparative study of D1S80 typing by capillary electrophoresis and sequencing

The D1S80 locus is very useful for personal identification in Japan. To obtain a correct allele over 45, we examined PCR amplification product of the allele over 45 both by direct sequencing and fragment analysis using capillary electrophoresis. Direct sequencing finally determined the allele as being 57. However, it was calculated to be an allele of 56 by comparison with size markers for capillary electrophoresis. The difference could be attributed to the electrophoretic size markers. This finding indicates that the direct sequencing may be useful to determine the allele over 45 in the D1S80 locus.     

Forensic toxicologic analysis of methamphetamine and amphetamine optical isomers by high performance liquid chromatography

Optical isomers (d and l) and racemic compounds (dl) of methamphetamine (MAMP) and amphetamine (AMP), and biologic materials including those substances, could be analyzed by high performance liquid chromatography. Examining the temperature for the analysis, 40 degrees C was the optimal condition in the reproducibility of separated MAMP-isomers. The reproducibility at the temperature did not vary significantly. The measured values of optical isomers were 0.116 +/- 0.012, 1.082 +/- 0.070 and 8.984 +/- 0.136 for the mixing ratios (l/d) of 0.111, 1.000, and 9.000, respectively. The detection limit for both d- and l-isomers was 25 ng. The analytic result of hair specimens from two stimulant abusers by the present method indicates that they contained only d-MAMP and d-AMP, which is believed to have the strongest pharmacologic effect among the optical isomers of MAMP. The coefficient of variation in the analysis of five replicate standards, prepared by adding 1,000 ng each of racemate MAMP and AMP to hair, was less than 4%. The measured value against l/d = 1.000 was 1.040 +/- 0.040 in MAMP and 0.980 +/- 0.030 in AMP. The detection limit for both racemate MAMP and AMP accumulated in hair was 250 ng. The analysis of the optical isomers by our method would contribute to identifying the smuggling routes or the illicit method.     

Evaluation of capillary electrophoresis performance through resolution measurements

The application of resolution measurements to an electrophoretic system can give a quantitative analysis of the health of that system. Capillary electrophoresis has become a routine method for the analysis of DNA and resolution measurements can be used to assess the resulting electropherogram. A number of methods are available to evaluate resolution and three methods are detailed in the current work. Parameters such as polymer concentration and column length were also examined in terms of resolution, and changes therein, if these parameters were modified.     

毛细管电泳在毒品检验中的应用

毛细管电泳因其自身特性而适用于毒品检测。本文重点对毛细管电泳的五种模式在毒品检验中的应用进行了综述和比较 ,包括各自检测方法的应用范围、优点和局限。     

Analysis of carbohydrates in seized heroin using capillary electrophoresis

Illicitly produced heroin is commonly cut with carbohydrates to increase bulk. The analysis of these solutes is important for legal and intelligence purposes. A capillary electrophoresis (CE) method was developed for the qualitative analysis of dextrose, lactose, sucrose, inositol, and mannitol in heroin exhibits. For this method, a 64 cm (55.5 cm to detector window) by 50 mum capillary was used with the Agilent Basic Anion Buffer modified to pH 12.1. This separation was performed at 25 degrees C with a voltage of 20 kV and indirect detection with 2,6-pyridinedicarboxylic acid as the visualization reagent. The methodology is also applicable for the screening of inorganic and organic anions using indirect detection, and acidic adulterants using direct detection. For a run time of 13 min, the relative standard deviation (n = 6) of the methodology was better than 0.36% for migration times and less than 2.6% for corrected peak areas. For the analysis of carbohydrates and acidic adulterants in seized heroin, excellent agreement was obtained between CE and nuclear magnetic resonance spectroscopy.     

Optimization of the separation of organic explosives by capillary electrophoresis with artificial neural networks

The separation of 12 explosives by capillary electrophoresis was optimized with the aid of artificial neural networks (ANNs). The selectivity of the separation was manipulated by varying the concentration of sodium dodecyl sulfate (SDS) and the pH of the electrolyte, while maintaining the buffer concentration at 10 mM borate. The concentration of SDS and the electrolyte pH were used as input variables and the mobility of the explosives were used as output variables for the ANN. In total, eight experiments were performed based on a factorial design to train a variety of artificial neural network architectures. A further three experiments were required to train ANN architectures to adequately model the experimental space. A product resolution response surface was constructed based on the predicted mobilities of the best performing ANN. This response surface pointed to two optima; pH 9.0-9.1 and 60-65 mM SDS, and pH 8.4-8.6 and 50-60 mM SDS. Separation of all 12 explosives was achieved at the second optimum. The separation was further improved by changing the capillary to an extended cell detection window and reducing the diameter of the capillary from 75 microm to 50 microm. This provided a more efficient separation without compromising detection sensitivity.     

毛细管电泳高频电导法检测饮料中γ-羟基丁酸

目的建立饮料中γ-羟基丁酸（GHB）的毛细管电泳高频电导法检测分析方法。方法样品经稀释后直接进样,采用反向分离模式,以0.5mmol/LNa3PO4＋1.5mmol/LNa2HPO4＋0.1mmol/LCTAB为电泳分离缓冲介质,分离电压为16kV,进样时间为20s进行电泳分离及高频电导检测。结果该实验条件下,6.5min内可实现样品快速分析。GHB在10.0～150μg/mL范围内线性关系良好,r=0.990,检出限为3.0μg/mL（S/N=3）。选择的3种饮料样本不同添加浓度日间和日内RSD均小于6%,回收率均在95%以上。结论采用本文方法,样品处理简单,方法快速、灵敏,操作方便,可作为饮料中GHB的一种快速筛选法在相关检测中选用。     

固相萃取毛细管区带电泳法测定全血中甲基苯丙胺

目的建立全血中甲基苯丙胺的固相萃取毛细管区带电泳法检验方法。方法血液采用OasisHLB固相萃取小柱直接萃取,BeckmanP/ACEMDQ毛细管电泳仪区带法分析。结果回归方程y=0.0083x-0.0164,线性范围5～75μg/mL(r=0.994),日内精密度RSD=2.22%,日间精密度RSD=5.31%,盐酸甲基苯丙胺质量浓度为25.0μg/mL的全血相对回收率(91.63±2.5)%。电泳分离良好,空白无干扰。结论本方法操作简便,适用于全血中甲基苯丙胺的检验。     

Optimization of a simple method for the chiral separation of methamphetamine and related compounds in clandestine tablets and urine samples by beta-cyclodextrine modified capillary electrophoresis: a complementary method to GC-MS

The chiral separation of (+/-)-methamphetamine, (+/-)-methcathinone, (+/-)-ephedrine and (+/-)-pseudoephedrine by means of beta-cyclodextrine modified capillary electrophoresis is described. The distribution of enantiomers in clandestine tablets and urine samples were identified. Several electrophoretic parameters such as the concentration of beta-cyclodextrin, temperature, the applied voltage and the amount of organic solvent required for successful separation were optimized. The method, as described herein, represents a good complementary method to GC-MS for use in forensic and clinical analysis.     

Allele distribution of 15 PCR-based loci in the Rwanda Tutsi population by multiplex amplification and capillary electrophoresis

A genetic study of 15 autosomal STRs is carried out (D2S1338, D3S1358, D5S818, D7S820, D8S1 79, D13S317, D16S359, D18S51, D19S433, D21S11, CSF1PO, FGA, TPOX, THO1, VWA) in a sample of unrelated Tutsis. The molecular phenotypes were determined by means of multiplex strategies (AmpFlSTR Identifiler PCR Amplification Kit, Applied Biosystems) followed by capillary electrophoresis.     

Sensitive determination of barbiturates in biological matrix by capillary electrophoresis using online large-volume sample stacking

In China, some forensic cases are caused by barbiturates. Thus, the determination of trace level barbiturates in body fluid is important for the poisoning investigation. In this study, an online large-volume sample stacking (LVSS) with polarity switching in capillary electrophoresis (CE) was applied for the sensitive determination of barbiturates. This technique involves injecting a large volume of sample into a capillary and removing the sample matrix plug out of the capillary by reversing the polarity. Quantitation limit obtained was 0.048, 0.057, 0.039, and 0.015 μg/mL for secobarbital, amobarbital, barbital, and phenobarbital (signal-to-noise ratio = 9). By using LVSS, the stacking was simply achieved at 171.7-, 169.7-, 202.7-, and 169.1-fold for the above four barbiturates. The relative standard deviation values of intraday and interday were <2.11% and 4.69%, respectively. Recoveries were ranged from 83.7 to 105.2%. Finally, the trace analysis method was applied to the analysis of real forensic specimens and has achieved satisfactory results.     

Simultaneous separation of different types of amphetamine and piperazine designer drugs by capillary electrophoresis with a chiral selector

The recent emergence of a new class of piperazine-type compounds has brought about the need for laboratory screening methods for both seized drugs and toxicological samples. These piperazine compounds, which include 1-benzylpiperazine (BZP) and 1-(3-trifluoromethylphenyl)piperazine (TFMPP), exhibit comparable physiological effects and can be substituted for the classic amphetamine-type drugs. We have optimized a chiral capillary electrophoresis (CE) separation that detects a set of 6 piperazine and 4 chiral amphetamine compounds in under 23 min using a 200 mM phosphate buffer at a pH = 2.8 with 20 mM hydroxypropyl- beta-cyclodextrin (HPbeta3CD). In addition to the above compounds, a series of "clandestine" BZP diHCl samples were also analyzed using this method to assess the ruggedness of the procedure. The novel CE separation was tailored to simultaneously detect these piperzine compounds in addition to amphetamine-type drugs. Distinct migration time and UV-spectral data were obtained for all compounds of interest.