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Estimation of postmortem interval(PMI)plays a crucial role in forensic study and identifica-tion work. Because of the unique anatomy location, vitreous humor is considered to be used for estima-ting PMI, which has aroused interest among scholars, and some researches have been carried out. The detection techniques of vitreous humor are constantly developed and improved which have been gradually applied in forensic science, meanwhile, the study of PMI estimation using vitreous humor is updated rapidly. This paper reviews various techniques and instruments applied to vitreous humor detection, such as ion selective electrode, capillary ion analysis, spectroscopy, chromatography, nano-sensing technology, automatic biochemical analyser, flow cytometer, etc., as well as the related research progress on PMI es-timation in recent years. In order to provide a research direction for scholars and promote a more accu-rate and efficient application in PMI estimation by vitreous humor analysis, some inner problems are also analysed in this paper.
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OBJECTIVE:To establish a method for the contents determination of microelements in Chrysanthemum indicum from different production fields. METHODS:Graphite furnace atomic absorption (GFAAS) was used to determine the contents of Pb,Cd and As;HGAAS was used to determination the content of Hg;and FAAS was used to determine the contents of Cu,Fe, Mn,Ca,Mg and Zn. RESULTS:The linear range was 0-50 μg/L for Pb(r=0.999 9),0-10 μg/L for Cd(r=0.999 2),0-50 μg/L for As(r=0.999 0),0-20 μg/L for Hg(r=0.999 5),0-5 μg/L for Cu(r=0.999 3),0-15 μg/L for Fe(r=0.999 8),0-2 μg/L for Mn (r=0.999 9),0-50 μg/L for Ca(r=1.000 0),0-20 μg/L for Mg(r=0.999 9)and 0-2 μg/L for Zn(r=0.999 8);RSDs of precision, stability and reroducibility tests were lower than 3%;recoveries were 94.25%~97.43%(RSD=1.07%)、94.97%~99.46%(RSD=1.68%)、96.25%~99.46%(RSD=1.09%,n=6)、96.61%~99.91%(RSD=1.26%,n=6)、94.11%~98.41%(RSD=1.68%,n=6)、93.11%~99.59%(RSD=2.73%,n=6)、93.11%~99.48%(RSD=2.63%,n=6)、93.01%~99.85%(RSD=2.49%,n=6)、95.13%~99.75%(RSD=1.58%,n=6)、94.08%~97.37%(RSD=1.18%,n=6),respectively. CONCLUSIONS:The method is simple,stable and reproducible,and can be used for the contents determination of microelements in C. indicum from different pro-duction fields.
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Objective To determine the chlorpyrifos in human blood by liquid chromatography-tandemmass spectrometry and to validate its application in poisoning cases. Methods The samples were extracted by a simple one-step protein precipitation procedure. Chromatography was performed on a Capcell Pack C18 mG II column (250 mm×2.0 mm, 5μm) using an isocratic elution of solvent A (0.1% formic acid-water with 2 mmol/L ammoniumacetate) and solvent B (methanol with 2 mmol/L ammoniumacetate) at 5∶95 (V∶V).Results The linearranged from5 to 500ng/mL (r=0.9987).Thelimitofdetection (LOD) and the lower limit of quantification (LLOQ ) were 2 ng/mL and 4 ng/mL , respectively. For this method, the precision and accuracy of intra-day and inter-day were <10% and 97.44%-101.10%, respectively. The re-sults in stability test of long-termfrozen were satisfied. The matrix effect, recovery and process efficien-cy were 64.97%-86.81%, 76.70%-85.52%, and 55.57%-66.58%, respectively. Conclusion This method can provide a rapid approach to chlorpyrifos extraction and determination in toxicological analysis of forensic and clinical treatment.
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Two p-phenylenediamine (p-PD)-imprinted polymers, P (MAA) and P (AA), were synthesized using methacrylic acid (MAA) and acrylamide(AA) as functional monomer, respectively, in order to prepare molecular recognition material with high selectivity for p-PD and explore the feasibility of methods such as molecular spectrometry and computational approach of quantum chemistry for the selection of functional mono mer with high imprinting efficiency.The molecular recognition properties of the imprinted polymers were evaluated by high performance liquid chromatography.The results indicated that P(AA) exhibited no imprint ing effect for p-PD, while P(MAA) can bind p-PD selectively(k' =3.57), which showed remarkable imprint ing effect (IF=2.95), and p-PD and its analogues o-phenylenediamine and p-aminobenzoic acid can almost realize baseline separation on P (MAA) column in the mobile phase of methanol.Furthermore, we made a comparative study on the interaction of p-PD with MAA and AA by spectroscopic techniques such as UV and fluorometry as well as HF/6-31G~* computational approach.The results demonstrated that the complex of p-PD-MAA was more stable than that of p-PD-AA, which can give a good explanation for the molecular recog nition properties of P (MAA) and P (AA).The study indicated that both molecular spectrometry (UV and fluorometry)and computational approach of quantum chemistry can be employed as efficient means for the selection of efficient functional monomer.The results showed that fluorometry is sensitive and convenient for the choice of functional monomer if the template molecule is fluorescent.