Effect of Gas Chromatography Temperature Program on the Association and Discrimination of Diesel Samples*†

Abstract: Five diesel samples were analyzed by gas chromatography–mass spectrometry (GC‐MS) using six GC temperature programs, aiming to investigate the effect of temperature program on association and discrimination of the samples. Temperature programs varied by ramp rate and incorporated one‐ or two‐step temperature ramps. Pearson product moment correlation coefficients and principal components analysis were used to evaluate differences in discrimination among the diesel samples afforded by each temperature program, based on the total ion chromatogram (TIC) and selected extracted ion profiles (EIPs). Association of diesel replicates and discrimination among samples based on the TIC and aromatic EIP were similar for all temperature programs based on scores plots. The alkane EIP was not useful in discriminating samples regardless of temperature program, because of similar alkane content of the diesel samples. The association and discrimination of diesel samples was largely unaffected by temperature programs that incorporated one‐ or two‐step temperature ramps.     

Raman Microspectroscopic Mapping: A Tool for Identification of Fused Materials in Fire Debris

Examination of fire debris can provide information about the types of materials which were present at the time of the fire to give insights for fire scene reconstruction and understanding compartment fire dynamics. This paper demonstrates the ability of Raman spectroscopy for material identification postfire in complex situations, such as the production of fused masses during fire dropdown. A validated Raman spectral library is combined with Raman mapping in three fire case studies, to determine the individual materials in the fused masses formed. The case studies accessed material combinations of several common polymers. Raman mapping was carried out on a 10 μm × 10 μm square of the masses. Material identification using this technique ranged from a high of 85% match to a low of 40% match. This work demonstrated that complex masses found in the fire debris can be resolved into the individual material components for identification and spatial distribution.     

Analysis of a soldered wire burnt in a fire

Fire investigators frequently encounter electrical wires with melted ends at fire scenes, which can provide useful information on the cause and development of the fire even when the melted ends result from the fires. A bead on a melted end of a wire was found in the area of origin of a massive fire that lasted for nearly a whole day, devastating a factory. The bead appeared to be the end of a wire soldered to a terminal. X-ray analysis showed that the bead is a tin-copper alloy. Although regular tin-lead solder was used in the factory, lead was not detected. This contradictory result stood in the way of fire investigation. Therefore, an unused wire soldered with tin-lead solder was heated in an electric furnace at 500 degrees C for 3 h for further examination. X-ray analysis of this wire showed that copper can be alloyed with tin while losing lead in a long-term heat in a fire.     

A new peptidase isozyme which may assist in the identification of vaginal debris

A characteristic peptidase has been identified in vaginal swab extracts. This enzyme, which has been termed vaginal peptidase, can be identified by its high anodal electrophoretic mobility in starch gel at pH 7.4 and its ability to hydrolyse the dipeptide substrate L-valyl-L-leucine. Vaginal peptidase was not detected in any of the body fluids or excretions commonly encountered in forensic stain analysis, other than vaginal debris. The use of this enzyme as a biochemical marker for the identification of vaginal debris in dried stains is discussed.     

Examination of misconceptions surrounding fatal fire victims

Fire deaths are not unusual in forensic investigative practice but due to the destructive nature of fire they are often very difficult to investigate. With the need to identify the deceased and the events surrounding the manner and cause of death, knowledge of thermally induced alteration to the human body is important. Within the fire investigation community, a number of misconceptions have been present for years regarding the protrusion of the tongue as an indicator of life during the fire, and fractured skulls as the result of brains boiling and skulls exploding. This work presents qualitative analysis on the experimental burning of 42 unembalmed human donated cadavers by the San Luis Obispo Strike Team (SLOFIST) on their annual Forensic Fire Death Investigation Course (FFDIC) between 2017 and 2019. Prior to burning, the position of the tongue within the dental arch was confirmed and sharp, blunt, surgical and gunshot trauma to the cranium documented. Temperature was recorded from ignition through to suppression with thermocouples present both within the scene and the body. Post burn analysis on the position of the tongue, observation of cranial fractures and presence of brain tissue were recorded and analysed in conjunction with thermocouple data, fire scene dynamics and body demographics. The results provide a more comprehensive understanding of the thermal environmental factors involved in producing the phenomena that facilitate these misconceptions, identifying that a more thorough understanding of individual fire scenes and their development is essential when interpreting alteration and injury to the body of the fatal fire victim.     

Fatality During Servicing of Fire Extinguisher

Fire extinguisher is an integral part of emergency responses to small fires. Different types of fire extinguisher exists; cartridge‐based fire extinguisher is commonly used. Despite their intended use for safety, such devices can become dangerous if not properly handled or maintained. This case report describes the death of a soldier from the explosion of a cartridge‐based fire extinguisher during routine servicing. The case is the first reported in the medical literature. A safety device like fire extinguisher can become dangerous if not handled with care and due steps should be taken for the maintenance of such devices before being operated in the public domain.