Determination of Herbicides Paraquat,Glyphosate, and Aminomethylphosphonic Acid in Marijuana Samples by Capillary Electrophoresis

In this work, two methods were developed to determine herbicides paraquat, glyphosate, and aminomethylphosphonic acid (AMPA) in marijuana samples by capillary electrophoresis. For paraquat analysis, sample was extracted with aqueous acetic acid solution and analyzed by capillary zone electrophoresis with direct UV detection. The running electrolyte was 50 mmol/L phosphate buffer (pH 2.50). For glyphosate and AMPA, indirect UV/VIS detection was used, as these substances do not present chromophoric groups. Samples were extracted with 5 mmol/L hydrochloric acid. The running electrolyte was 10 mmol/L gallic acid, 6 mmol/L TRIS, and 0.1 mmol/L CTAB (pH = 4.7). The methods presented good linearity, precision, accuracy, and recovery. Paraquat was detected in 12 samples (n = 130), ranging from 0.01 to 25.1 mg/g. Three samples were positive for glyphosate (0.15–0.75 mg/g), and one sample presented AMPA as well. Experimental studies are suggested to evaluate the risks of these concentrations to marijuana user.     

顶空气质联用法测定腐败血、肝检材中CO

目的研究CO中毒腐败血、肝组织检材中CO的HS/GC/MS检测。方法用HS/GC/MS法分析碳氧血红蛋白(COHb)血的线性范围。配制10%、30%、50%、70%浓度COHb血样,分别在室温、冷藏、冷冻条件下保存,分别在当日、第4、14、45d进行测定,比较实验结果。腐败肝组织由雄性健康家兔通CO气体致死,当天解剖,家兔肝常温隔绝空气保存并放35d至腐败,期间进行不定期顶空测定分析。结果制备的COHb血在0-100%之间有良好的线性关系Y=2.4X+2.2(r=0.9995)。以此方法测定家兔CO中毒致死的COHb新鲜血的浓度和4℃下放置45dCOHb腐败血,结果表明温度对血样中COHb%的测定影响最大。采用HS/GC/MS法检测,每次只需0.25ml血样或1g肝脏,分析一次时间只需3min,均可检测出新鲜检材和常温放置45d的腐败肝组织检材CO的含量。结论HS/GC/MS法能检出CO中毒的腐败生物检材中CO。     

气相色谱法测定牙本质中天冬氨酸消旋化程度推断年龄的研究

本文应用手性毛细管柱气相色氨谱法，以酸性异丙醇、三氯乙酸酐为衍生化试剂，对不同年龄人的27颗第一磨牙牙本质中D型与L型天冬氟酸的浓度进行了测定，并计算了二者的比率，建立了消旋化程度与年龄的回归方程，r＝0．9568，SD＝4．5岁，本研究为用牙齿推断人的年龄提供了一个比较客观、准确的新手段。     

Phenolphthalein False‐Positive Reactions from Legume Root Nodules

Presumptive tests for blood play a critical role in the examination of physical evidence and in the determination of subsequent analysis. The catalytic power of hemoglobin allows colorimetric reactions employing phenolphthalein (Kastle‐Meyer test) to indicate “whether” blood is present. Consequently, DNA profiles extracted from phenolphthalein‐positive stains are presumed to be from blood on the evidentiary item and can lead to the identification of “whose” blood is present. Crushed nodules from a variety of legumes yielded phenolphthalein false‐positive reactions that were indistinguishable from true bloodstains both in color quality and in developmental time frame. Clothing and other materials stained by nodules also yielded phenolphthalein false‐positive reactivity for several years after nodule exposure. Nodules from leguminous plants contain a protein (leghemoglobin) which is structurally and functionally similar to hemoglobin. Testing of purified leghemoglobin confirmed this protein as a source of phenolphthalein reactivity. A scenario is presented showing how the presence of leghemoglobin from nodule staining can mislead investigators.     

国产NuHi-POP4与ABI POP-4在毛细管电泳分离效果的比较

目的比较国产基因分离胶NuHi-POP4与美国产商品ABI POP-4在法医鉴定应用中的分离性能。方法以国产基因分离胶NuHi-POP4和美国产的ABI POP-4为研究对象,分别考察其在毛细管电泳过程中对标准品LIZ500和实际样品的分离效果,并统计其电泳参数,包括电泳时间、电流、单碱基分辨率以及线性关系等,从而来比较两种胶的分离性能,评价其性能。结果 NuHi-POP4与ABI POP-4相比,不仅可以显著缩短内标和样品的分析时间,同时还表现出电流稳定、分辨率高、线性关系好等特点。结论国产NuHi-POP4与美国ABI POP-4相比,同样具有稳定、快速、高分辨等优势,结果准确可靠。     

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。     

Increased sensitivity for amplified STR alleles on capillary sequencers with BigDye XTerminator™

Free fluorescent dyes from PCR primers or amplification products can interfere with the interpretation of STR alleles in an electropherograph especially when the profiles have a low signal intensity. These artefacts can be removed by using a simple procedure based on BigDye^® XTerminator™. This procedure requires limited amounts of PCR product, allows to do several loadings on a capillary sequencer starting from the same purified PCR product and also increases the sensitivity for detection of less amplified loci.     

Determination of multiple drugs of abuse in human urine using dispersive liquid–liquid microextraction and capillary electrophoresis with PDA detection

A new method was developed for pre-concentration and determination of multiple drugs of abuse in human urine using dispersive liquid–liquid microextraction (DLLME) and capillary electrophoresis (CE) with photodiode array detection. The method was based on the formation of tiny droplets of an organic extractant in the prepared sample solution using water-immiscible organic solvent (chloroform) dissolved in water-miscible organic dispersive solvent (isopropyl alcohol). The organic phase, which extracted eight drugs of abuse from the prepared urine solution, was separated by centrifugation. The sedimented phase was transferred into a small volume CE auto-sampler vial with 10 µL of 1% HCl methanol solution and evaporated to dryness. The residue was reconstituted in lidocaine hydrochloride (internal standard) aqueous solution and introduced by electrokinetic injection into CE. Under the optimum conditions, acceptable linear relationship was observed in the range of 3.0–500 ng/mL with the correlation coefficient (r) of 0.9982–0.9994 for spiked urine samples. The limit of detection (LOD) (S/N = 3) was estimated to be 1.0 ng/mL. A recovery of 75.7%–90.6% was obtained for spiked samples. The mean relative error (MRE) was within ±7.0% and the relative standard deviation (RSD) was less than 6.9%. The proposed DLLME-CE procedure offers an alternative analytical approach for the sensitive detection of drugs of abuse in real urine samples.

Key points

• The dispersive liquid-liquid microextraction (DLLME) was involved for the determination of drugs in urine with capillary electrophoresis with photodiode array detection (CE-PDA).
• Good linearity, sensitivity, recovery and precision were achieved.
• The proposed method was eco-friendly with microliter scale solvent consumption.

     

Developmental validation of the novel six-dye GoldeneyeTM DNA ID System 35InDel kit for forensic application

Insertion/deletion polymorphisms (InDels) have been treated as a prospective and helpful genetic marker in the fields of forensic human identification, anthropology and population genetics for the past few years. In this study, we developed a six-dye multiplex typing system consisting of 34 autosomal InDels and Amelogenin for forensic application. The contained InDels were specifically selected for Chinese population with the MAF ≥ 0.25 in East Asia, which do not overlap with the markers of Investigator^® DIPplex kit. The typing system was named as Goldeneye^TM DNA ID System 35InDel Kit, and a series of developmental validation studies including repeatability/reproducibility, concordance, accuracy, sensitivity, stability, species specificity and population genetics were conducted on this kit. We confirmed that the 35InDel kit is precise, sensitive, species specific and robust for forensic practice. Moreover, the 35InDel kit is capable of typing DNA extracted from forensic routine case-type samples as well as degraded samples and mixture samples. All markers are proved to be highly polymorphic with an average observed heterozygosity (He) of 0.4582. The combined power of discrimination (CPD) is 0.999 999 999 999 978 and the combined power of exclusion in duos (CPE_D) and trios (CPE_T) are 0.978 837 and 0.999573, respectively, which are higher than those of the Investigator^® DIPplex kit. Thus, the Goldeneye^TM DNA ID System 35InDel kit is suitable for forensic human identification and could serve as a supplementary typing system for paternity testing.Supplemental data for this article is available online at https://doi.org/10.1080/20961790.2021.1945723 .     

大鼠脑、骨髓细胞核DNA降解推断死后间隔时间的研究

目的检测大鼠死后不同温度下脑、骨髓细胞核DNA降解规律，寻找推断早期死亡间隔时间（PMI）的新参数。方法10℃和20℃下，大鼠死后0～40h内，每隔4h取材脑组织和骨髓，单细胞凝胶电泳（SCGE）检测DNA降解程度，线性回归分析比较彗星参数HeadDNA％、尾长（TL）、Olive尾矩（TM）与PMI的关系。结果大鼠死后早期脑细胞、骨髓细胞核Head DNA％随着PMI逐渐下降的程度不同，20℃脑细胞核Head DNA％降解速率较快。与骨髓细胞相比，脑细胞核Head DNA％与PMI线性关系较好。与TL、TM相比，Head DNA％与PMI的线性关系较好。结论脑组织是利用SCGE检测DNA降解推断PMI的合适检材。Head DNA％较TL、TM推断PMI的价值更高。