Nano-interface driven electrochemical sensor for pesticides detection based on the acetylcholinesterase enzyme inhibition.

Forensic Science Laboratories usually receive numerous cases of suicidal, accidental, and homicidal poisoning most often involving organophosphorus (OP) pesticides. The toxicity of the OP pesticides arises due to their ability to inhibit the activity of acetylcholinesterase (AChE), a cholinergic enzyme that is essential for the proper functioning of the central nervous system. Conventional techniques which are currently in use for pesticide detection are time-consuming, need upskilled technicians as well as suffer from low sensitivity. Therefore, the more rapid and sensitive electrochemical biosensors based on the principle of AChE enzyme inhibition have emerged out to be a simple and promising alternative to the conventional techniques. Since, most of the time, the poison isolated from biological material in poisoning cases is in nM quantities, an attempt has been made for the development of biosensor with enhanced sensitivity in the nM range using reduced graphene oxide (rGO) and zinc oxide nanoflowers (ZnONFs). The rGO and ZnONFs were synthesized chemically and deposited electrochemically on the Au electrode. AChE was immobilized onto this prepared nano-interface (ZnONFs/rGO/Au) through chitosan and glutaraldehyde cross-linking. The fabricated sensor was characterized step by step with cyclic voltammogram and electrochemical impedance spectroscopy. This advanced nanomaterials based techniques has been explored for detecting pesticides in visceral samples. The limit of detection (LOD) for the present sensor was 0.01 nM for OP pesticides.

Identification of source mobile hand sets using audio latency feature.

An experiment has been carried out for determination of source of digital audio recording using audio latency feature of mobile phones. The legal requirement of the source correspondence with the audio recordings in question has driven the necessity of such study. The evaluation is based on 300 audio recordings recorded with ten mobile handsets of MOTOROLA make but different model in three different format "3gp", "wav" and "m4a" format (ten audio recording in each format) recorded in stereo signal at 16 kHz and in different recording sessions using EASY VOICE RECORDER application. Adobe audition 3.0 software is used for analysis. The analysis of audio latency has been carried out in a set of ten mobile handsets having multimedia capability. The result of this study shows that the audio latency of mobile handsets of same make but different model carry the specific feature of latency and such audio latency is robust for establishing the source of audio recordings.

Zinc as a marker in viscera of suspected metal phosphide poisoning: a study by neutron activation analysis.

Zinc as a marker element in the viscera of suspected metal phosphide poisoning has been studied during the present work. Neutron activation analysis (NAA) has been employed to detect and quantify the concentration of zinc in the viscera/stomach portion. The methodology has been developed on simulated and real life viscera samples to quantify the amount of zinc using NAA. The results obtained by NAA for real-life samples have been validated using a complementary analytical technique (viz. differential pulse anodic stripping voltammetry), and the values obtained were in good agreement, within +/- 5-8%. This exercise could be useful in medico-legal field for framing a definitive opinion about zinc phosphide poisoning.

Use of egg yolk antibody (IgY) as an immunoanalytical tool in the detection of Indian cobra (Naja naja naja) venom in biological samples of forensic origin.

An immunoglobulin Y (IgY) based indirect double antibody sandwich enzyme linked immunosorbent assay (ELISA) was developed for the detection of Indian cobra (Naja naja naja) venom in the biological samples of forensic origin. Polyclonal antibodies were raised and purified from chick egg yolk and rabbit serum. The cobra venom was sandwiched between immobilized affinity purified IgY and the rabbit IgG. The detection concentration of cobra venom was in the range of 0.1 to 300ng. The calibration plot was based on linear regression analysis (y=0.2581x+0.4375, r(2)=0.9886). The limit of detection of the assay was found to be 0.1ng. The coefficient of variation (CV) of different concentrations of working range in inter (n=6) and intra-assay (n=6) was observed to be less than 10%. The recovery of venom was found to be in the range of 80-99%, when different concentrations (0.002, 0.1, 0.2, 1, and 2microg) of cobra venom were spiked to pooled normal human serum (ml(-1)). No cross reactivity was observed with krait and viper venom in the immunoassay system in the concentration range of 0.1-1000ng. The method was initially, validated by analyzing specimens (autopsy) of experimental rats injected with cobra venom (1.2mgkg(-1) body mass). Further, human specimens (autopsy and biopsy) of snake bite victims of forensic origin were also analyzed. The methodology developed may find diagnostic application in forensic laboratories.

Source identification of Indian opium based on chromatographic fingerprinting of amino acids.

Total and free pool of amino acids was determined in Indian opium samples using liquid chromatography (LC) with post-column opthalaldehyde derivatization followed by its fluorimetric detection. The limit of detection (LOD) was found to be in the range of 2-10 pmol with a signal to noise ratio of 3:1 and limit of quantitation (LOQ) was found to be in the range of 7-31 pmol with a signal to noise ratio of 10:1. The recovery of amino acids was found to be in the range of 86-103%. A total of 124 Indian opium samples were collected from the states of Madhya Pradesh (MP), Uttar Pradesh (UP) and Rajasthan (Raj), covering 14 licit opium growing divisions of India were chromatographically fingerprinted for the presence of various amino acids. The amino acids identified in sample hydrosylate included D, T, S, S, G, A, V, I, L, Y, F, H, K and R, while the analysis of free pool of amino acids (80% aqueous ethanol extract) indicated the presence of D, T, S, E, A, V, I, L, Y, H, K respectively. Multiple discriminant analysis was applied to the quantitative total amino acid data to determine an optimal classifier in order to evaluate the source of Indian opium. The foremost amino acid variables that accounted for the true discrimination were identified as D, E, G, A, F and K in evaluating the geographical origin of Indian opium and the predictive value based on the discriminant analysis was found to be 90% in relation to the source of opium samples. Chemometrics performed with amino acid analytical data was used successfully in discriminating the licit opium growing divisions of India into three major groups, viz. groups I, II and III. The methodology developed may find wide application in forensic analysis.

Simple liquid chromatographic method for the rapid and simultaneous determination of propoxur and its major metabolite isopropoxy phenol in rat blood and urine using solid-phase extraction.

This research paper describes the development and validation of an analytical method for the simultaneous determination of propoxur and isopropoxy phenol (IPP, a major metabolite) in both blood and urine of rat using reversed-phase high-performance liquid chromatography (HPLC) employing solid-phase extraction (SPE). Sample purification was performed using a weak cation-exchange cartridge (Isolute CBA). Separation was achieved by HPLC with UV detection at 270 nm. Recoveries of propoxur and IPP from blood and urine by SPE exceeded 85%. The validated calibration range for propoxur is from 0.5 to 100 microg/L and 2 to 100 microg/L for IPP in both rat blood and urine. The limit of quantitation for propoxur in blood and urine is 0.5 and 0.8 pg/L, respectively, and 2.0 and 4.2 microg/L, respectively, for IPP. Validation results on specificity, sensitivity, linearity, precision, accuracy, and stability are shown. The applicability of the method was demonstrated by the analysis of urine and blood from rats that were orally fed propoxur at minimum dose.

Quinacrine sterilization (QS) among high-risk women: a study of 134 cases.

OBJECTIVE: To determine if quinacrine sterilization (QS) is safe and effective in women at high risk for surgery. METHODS: A trial was initiated at the Government Medical College in Patiala, India, in December 1993. Patient intake was terminated in July 1999 and the cut-off date for this analysis was March 31, 2003. Using a modified IUD inserter, seven 252 mg quinacrine pellets with 50 mg of diclofenac were transcervically inserted into the uterus. DMPA 150 mg was administered IM at the time of the first insertion as a back-up contraceptive. This same combination was inserted a month later. A total of 134 women underwent QS. Of these, 92 were considered to be at high risk for surgery, 27 were afraid of surgery or voluntarily opted for QS, and 15 had had failed surgical sterilization or surgery was found not to be technically feasible. Follow-up was scheduled for 1, 3, 6 and 12 months, and then annually after the second insertion or whenever side effects or complications were experienced. RESULTS: Mean follow-up was 7.2 years. No pregnancies or serious complications were experienced. CONCLUSION: QS is a safe and effective option for women at high risk of surgical complications.

Determination of diazepam in cold drinks by high-performance thin-layer chromatography.

A methodology was developed for the detection and quantitation of diazepam in non-alcoholic carbonated beverages and fruit drinks which are adulterated for criminal motives. The extraction of diazepam from the five brands of spiked and simulated cold drinks was carried out at pH 8.5 by two different extraction solvents viz., diethylether and chloroform. The identification of diazepam was done on the basis of RF values and in situ UV spectra. The quantitation was carried out by densitometric scanning of the chromatogram at a wavelength of 230 nm. The method is rapid and reliable for qualitative and quantitative analysis of cold drinks adulterated with diazepam and can be used by law enforcement laboratories for routine analysis.