[Identification of the relative age of iron gall ink in handwriting by capillary electrophoresis using the Fe(â ¡)/Fe(â ¢) ratio].

Identifying the relative age of iron gall ink in the handwriting on a questioned file is highly significant for court science, because it serves as important evidence for solving criminal cases and in confirming the authenticity of historical documents. This is because many criminal cases involve analysis of forged documents to conclude whether an entire document is as old as purported, or whether the entire text in the document was written at the same time. In this paper, a novel approach based on capillary electrophoresis (CE) to estimate the relative age of iron gall ink-written texts is discussed. Two kinds of chelating agents, 1,10-phen and CDTA, were used for the simultaneous determination of Fe(Ⅱ) and Fe(Ⅲ) by CE. The stability constants of ï¼»Fe(Ⅱ)-(phen)3ï¼½2+ and ï¼»Fe(Ⅱ)-CDTAï¼½2- complexes are log ß 3=21.3 and log K=18.2, respectively, while the corresponding values of ï¼»Fe(Ⅲ)-(phen)3ï¼½3+ and ï¼»Fe(Ⅲ)-CDTAï¼½- complexes are log ß 3=14.1 and log K=29.3. First, specific binding between the two kinds of chelating agents and the ferrous/ferric ions was investigated. The results confirmed specific binding between Fe(Ⅱ) and 1,10-phen as well as that between Fe(Ⅲ) and CDTA. Preliminary studies also showed that Fe(Ⅱ) in the iron gall ink was relatively stable in the ink tank due to the low pH of commercial inks; hence, the oxidation of Fe(Ⅱ) in the tank was considered to be negligible. However, when the gall ink was exposed on a paper, sulfuric acid in the ink was gradually consumed by the cellulose of paper, thus causing gradual oxidation of Fe(Ⅱ) in the written text. Changes in the peak area ratio of Fe(Ⅱ) and Fe(Ⅲ) with aging were monitored: the older the ink in the writing, the smaller is the Fe(Ⅱ)/Fe(Ⅲ) ratio. Hence, the Fe(Ⅱ)/Fe(Ⅲ) ratio could be used for estimating the relative age of iron gall ink in writing. The Fe(Ⅱ)/Fe(Ⅲ) ratio was determined by CE, and the ratio extracted from the questioned handwriting ink was compared with that extracted from the entire document to confirm whether the entire text written at the same time. The keys to the success of this technique are establishing a suitable procedure for extracting the Fe(Ⅱ) and Fe(Ⅲ) species in the handwriting ink and a CE separation procedure. The optimized sample pretreatment procedure is as follows: (1) an ink-drawn line of 1 cm length was cut and placed in a 2 mL Eppendorf tube; (2) then, 0.5 mL of 5.0 mmol/L 1,10-phen was added to the EP tube for chelation with Fe(Ⅱ), and the mixture was subjected to vibration on a vortex mixer; (3) within 60 s, 0.5 mL of 20 mmol/L CDTA was added to the sample tube for chelation with Fe(Ⅲ); (4) the tube was strongly vibrated for 10 min on a vortex mixer; (5) after centrifugation at 10000 r/min for 15 min, the supernatant was decanted into another tube for CE analysis. The optimized conditions for the CE analysis are as follows: 100 mmol/L of pH 9.2 H3BO3-Na2B4O7 buffer, 20 kV applied voltage, sample injection (1.379 kPa, 5s), fused-silica capillary dimensions 40.2 cm×75 µm i.d. (30 cm to the detector), and 254 nm detection wavelength. Meanwhile, small amounts of 1,10-phen and CDTA were added to the buffer solution to ensure stability of the formed complexes during the CE run in the capillary and to maintain the metal ions in their original oxidation state. Finally, two kinds of iron gall ink samples were tested to evaluate the applicability of the developed method. The Fe(Ⅱ)/Fe(Ⅲ) ratios of ink sample 1 and ink sample 2 changed from 1.79 to 0.45 and from 2.67 to 0.3, respectively, from the 1st day to the 75th day after writing. The results demonstrate that the developed method can be used to highlight fraudulent insertion of information and provide important guidance for the forensic analysis of the relative age of gall ink in handwriting.

Phosphine Analysis in Postmortem Specimens Following Inhalation of Phosphine: Fatal Aluminum Phosphide Poisoning in Children.

Phosphine is an insecticide for the fumigation of grains, animal feed, and leaf-stored tobacco, and it was used as a rodenticide in bulk grain stores. Phosphine poisoning may occur after accidental inhalation of phosphine, sometimes leading to death. Analysis of phosphine and its metabolites in postmortem specimens from seven fatal cases was conducted in this study, as well as postmortem specimens collected from rabbits exposed to phosphine. The total phosphine in postmortem specimens was analyzed by headspace gas chromatography coupled with mass spectrometry. Diagnosis of aluminum phosphide poisoning was made after postmortem toxicological analysis and confirmed by police investigation. The deaths of the children occurred after inhalation of phosphine generated from aluminum phosphide contacting moisture in the air in all seven fatal cases. The concentration of total phosphine in the biological fluids and tissues of victims ranged from 0.2 to 4.7 µg/mL (µg/g). Animal experiments demonstrated that the phosphine generated from aluminum phosphide could rapidly cause death. The toxicological analysis of postmortem specimens provides useful information in diagnosis of aluminum phosphide poisoning in forensic science. As an important fumigation pesticide, aluminum phosphide deserves special attention, especially since there is no specific antidote and there is a high fatality rate.

Determination of arsenic and lead in single hair strands by laser ablation inductively coupled plasma mass spectrometry.

The purpose of this study was to develop matrix-matched hair standards and a LA-ICP-MS technique for determination of the As and Pb in a single human hair using single spot scan mode. These results could subsequently be used to infer when the element entered the body. This study was conducted in two parts. First, a method was developed and validated for the elemental analysis of hair by LA-ICP-MS. A calibration strategy in LA-ICP-MS was developed using prepared matrix-matched laboratory hair standards doped with analytes of interest at a defined concentration. The use of hair strand standards enables calibration curves to be obtained by plotting the analyte ion (M+) intensity normalized to34S+(the ratio M+/34S+) as a function of the concentration determined by ICP-MS of the acidic digests. The linear correlation coefficients (R2) of the calibration curves for the analytes As and Pb were typically between 0.9970 and 0.9998, respectively. Second, an actual hair was measured using the developed method. The spatial distribution of As along the hair was observed in a hair sample from a leukaemia patient treated with arsenic trioxide (As2O3). The actual and estimated times over which the drug entered the body were compared and discussed.

Comparative normal/failing rat myocardium cell membrane chromatographic analysis system for screening specific components that counteract doxorubicin-induced heart failure from Acontium carmichaeli.

Cell membrane chromatography (CMC) derived from pathological tissues is ideal for screening specific components acting on specific diseases from complex medicines owing to the maximum simulation of in vivo drug-receptor interactions. However, there are no pathological tissue-derived CMC models that have ever been developed, as well as no visualized affinity comparison of potential active components between normal and pathological CMC columns. In this study, a novel comparative normal/failing rat myocardium CMC analysis system based on online column selection and comprehensive two-dimensional (2D) chromatography/monolithic column/time-of-flight mass spectrometry was developed for parallel comparison of the chromatographic behaviors on both normal and pathological CMC columns, as well as rapid screening of the specific therapeutic agents that counteract doxorubicin (DOX)-induced heart failure from Acontium carmichaeli (Fuzi). In total, 16 potential active alkaloid components with similar structures in Fuzi were retained on both normal and failing myocardium CMC models. Most of them had obvious decreases of affinities on failing myocardium CMC compared with normal CMC model except for four components, talatizamine (TALA), 14-acetyl-TALA, hetisine, and 14-benzoylneoline. One compound TALA with the highest affinity was isolated for further in vitro pharmacodynamic validation and target identification to validate the screen results. Voltage-dependent K(+) channel was confirmed as a binding target of TALA and 14-acetyl-TALA with high affinities. The online high throughput comparative CMC analysis method is suitable for screening specific active components from herbal medicines by increasing the specificity of screened results and can also be applied to other biological chromatography models.

Method development and validation for determining 1,3-butadiene in human blood by gas chromatography-mass spectrometry and head-space gas chromatography.

To develop a simple, validated method for identifying and quantifying 1,3-butadiene (BD) in human blood by gas chromatography-mass spectrometry (GC-MS) and head-space gas chromatography (HS-GC). BD was identified by GC-MS and HS-GC, and quantified by HS-GC. The method showed that BD had a good linearity from 50 to 500 microg/mL (r > 0.99). The limits of detection and quantification were 10 microg/mL and 50 microg/mL, respectively. Both the intra-day precision and inter-day precision were < 6.08%, and the accuracy was 96.98%-103.81%. The method was applied to an actual case, and the concentration of BD in the case was 242 microg/mL in human blood. This simple method is found to be useful for the routine forensic analysis of acute exposure to BD.

Distinguishing heroin abuse from codeine administration in the urine of Chinese people by UPLC-MS-MS.

Heroin is a highly addictive drug, and heroin abuse is considered to be a serious criminal act. The major metabolite of heroin, morphine, can usually be detected as evidence of heroin abuse. However, it is difficult to determine heroin use when morphine and codeine are both detected, because codeine use will also result in the presence of morphine in urine. Therefore, it is important to distinguish heroin abuse from codeine administration. In this study, urine samples from 21 volunteers with various ingestion patterns of a compound codeine phosphate oral solution were used as negative controls, and urine samples from 89 alleged heroin users were used as positive controls. Urine from single and multiple doses of codeine administration were collected at different time points for a systematic comparison. After protein precipitation, the urine samples were analyzed for the presence of free morphine, free codeine and their metabolites by ultra-performance liquid chromatography-tandem mass spectrometry. The method of percentiles, with median and standard interquartile ranges, was used to describe and analyze the data based on the normality of the distribution. The ratios of concentration of morphine and morphine to codeine were found to be the possible criteria to distinguish heroin users from codeine users in Chinese people.

[Measurement of acetonitrile in blood and urine by head-space gas chromatography].

OBJECTIVE: To establish the method for measurement of acetonitrile in blood and urine by head-space gas chromatography. METHODS: DB-ALC1 (30 m x 320 microm x 1.8 microm) and DB-ALC2 (30 m x 320 microm x 1.2 microm) capillary column were used to measure the acetonitrile in blood and urine with the isopropanol as internal standard reference. RESULTS: The limits of detection of acetonitrile in both blood and urine were 0.5 microg/mL, with a linear range of 5-1000 microg/mL (r = 0.999).The accuracy of this method was 93.2%-98.0%. The RSD for the intra-day and inter-day were less than 3.7%. CONCLUSION: The method is capable for measurement analysis of acetonitrile in blood and urine.

[Determination of 24 elements in human hair by ICP-MS using microwave digestion].

OBJECTIVE: To establish an inductively coupled plasma-mass spectrometry (ICP-MS) method for determination of 24 elements in human hair. METHODS: The samples were digested with microwave digestion instrument. ICP-MS was applied to determine 24 elements in human hair using indium (115In) as an internal standard. The established method was applied to determine element concentration in normal group (56 samples) and heroin abuse group (10 samples). RESULTS: The limits of detection ranged from 0.000 3 microg/g to 10.14 microg/g. Measured value of the standard materials were basically consistent with the standard value. The contents of magnesium, gallium and barium in hair of heroin addicts decreased after rehabilitation treatment. CONCLUSION: The method is sensitive and accurate for determination of 24 elements in human hair.