Toxicological analysis of azide and cyanide for azide intoxications using gas chromatography

Rapid and simple identification of trace amounts of sodium azide in beverages and bodily fluids followed by derivatization and liquid chromatography-electrospray ionization tandem mass spectrometry

RATIONALE

Sodium azide (NaN3 ) is a toxic chemical agent to humans by ingestion and inhalation with a growing number of intentional exposures and accidental cases over the last few decades. Due to its low molecular weight and lack of any chromophore, its retention and detection by reverse-phase liquid chromatography-ultraviolet-mass spectrometry methods are a challenging task.

METHODS

To be able to confirm azide exposure, we have developed a method to identify azide in both beverages and bodily fluids. The identification of azide (N3 - ) is based on derivatization with N-(2-(bromomethyl)benzyl)-N,N-diethylethanaminium bromide (CAX-B) at 25°C for 15 min followed by LC/ESI-MS/MS analysis, with no other sample preparation.

RESULTS

The azide after derivatization (CAX-N3 ) was stable, retainable by LC and sensitively detected by selected reaction monitoring. The ESI-MS/MS fragmentation of the M+ precursor ion produced characteristic product ions at m/z 118, 100, 91 and 86. The calibration curves for CAX-N3 showed linearity over two orders of magnitude with R2 value of 0.99. Low limits of identification of 0.1-0.5 ng/mL were obtained in all investigated matrices (drinking water, tea, orange juice, plasma and urine).

CONCLUSIONS

Compared with previously reported chromatography-based methods, this method that was based on derivatization and LC/ESI-MS/MS analysis was substantially more sensitive, simpler and faster. The method can be used for forensic investigation to confirm azide exposure from fatal use to much smaller intoxication dose.

Internet-Purchased Sodium Azide Used in a Fatal Suicide Attempt: A Case Report and Review of the Literature

There has been a significant increase in sodium azide intoxications since the 1980s. Intoxications caused by sodium azide are becoming increasingly prevalent in the Netherlands as a result of its promotion for the purpose of self-euthanasia. The mechanism of toxicity is not completely understood but is dose-dependent. The presented case describes a suicide by sodium azide of a young woman (26 years old) with a history of depression and suicide attempts. The decedent was found in the presence of prescription medicine, including temazepam, domperidone in combination with omeprazole, and the chemical preservative sodium azide. Quantitative toxicology screening of whole blood revealed the presence of 70 µg/L temazepam (toxic range > 1000 µg/L) and 28 mg/L sodium azide (fatal range: 2.6-262 mg/L). Whole blood qualitative analysis revealed the presence of temazepam, temazepam-glucuronide, olanzapine, n-desmethylolanzapine, and acetaminophen. In circles promoting sodium azide, it is recommended to use sodium azide in combination with medications targeting sodium azide's negative effects, such as analgesics, antiemetics, and anti-anxiety drugs. The medicines recovered at the body's location, as well as the results of the toxicology screens, were consistent with the recommendations of self-euthanasia using sodium azide.

The dark side of social media: Two deaths related with chloroform intoxication

A suicide pact is an agreement between people to commit suicide together, which usually takes place at the same time, in the same place, by using the same method. Social media serve as a way of communication between people. Thus, they use such platforms to find potential suicide pact partners. Chloroform, although being regarded to as a slightly forgotten poison, is still linked to homicide and suicide cases. Death due to an acute chloroform ingestion may be a result of central nervous system depression. In this paper, we present application of headspace gas chromatographic method using a dual column/dual flame ionization detector (HS-GC-FID/FID) for the determination of chloroform in two fatal intoxication cases, as well as chloroform stability study. Analysis of biological samples revealed chloroform concentrations of 135.8, 16.1, 8.1, and 37.1 µg/ml in blood, urine, vitreous humor, and bile, respectively. Kidney, liver, and muscle specimens contained 119.5, 99.6, and 28.4 µg/g of chloroform, respectively. The results of stability studies indicate the highest decrease of chloroform in room temperature, so it is advised to store samples in a freezer. The addition of sodium fluoride is recommended as in blood samples collected to the test tubes without any preservative agent, the detection of chloroform after 91 days is almost impossible. It is important to emphasize that even old poisons can cause a lot of concerns today, as here described cases are linked to chloroform intoxication, as well as with possible danger which social media bring about nowadays.

A novel procedure for stabilization of azide in biological samples and method for its determination (HS-GC-FID/FID)

Sodium azide is an old poison with toxicity comparable to potassium cyanide. It would seem to be completely forgotten however, between 2000 and 2020, the number of intentional ingestions and murders committed with sodium azide significantly increased. Furthermore, due to its extreme instability, sodium azide is difficult to detect, which poses an additional risk when used to commit a crime. In this study, the epidemiology of sodium azide exposures between 1920 and 2020 was investigated. For the determination the azide concentration in biological samples, a simple, precise and selective headspace gas chromatography method (HS-GC-FID/FID) was developed and fully validated. The limit of quantification was 0.65 µg/mL; and the limit of detection was 0.35 µg/mL; precision and accuracy did not exceed 20%. The stability study was conducted for various biological fluids (urine, bile, blood, gastric content) for 91 days in the refrigerator (4 °C) and the method for stabilization of azide was presented. The addition of a mixture of borax and sodium fluoride (w/w 3:1) to the test tubes can stabilize this poison. The described unique technique of collecting the biological samples poses a great potential for azide detection in clinical and toxicology laboratories even long time after human exposure to this substance.

Toxicological analysis of azide and cyanide for azide intoxications using gas chromatography

Azide is a highly toxic chemical agent to human being. Accidental, but also intentional exposure to azide occurs. To be able to confirm azide ingestion, we developed a method to identify and quantify azide in biological matrices. Cyanide was included in the method to evaluate suggested in vivo production of cyanide after azide ingestion. Azide in biological matrices was first derivatized by propionic anhydride to form propionyl azide. Simultaneously, cyanide was converted into hydrogen cyanide. After thermal rearrangement of propionyl azide, ethyl isocyanate was formed, separated together with hydrogen cyanide by gas chromatography (GC) and detected using a nitrogen phosphorous detector (NPD). The method was linear from 1.0‐100 µg/mL for both analytes, and azide was stable in human plasma at −20°C for at least 49 days. Azide was measured in the gastric content of two cases of suspected azide ingestion (case 1:1.2 mg/mL, case 2:1.5 mg/mL). Cyanide was only identified in the gastric content of case 1 (approximately 1.4 µg/mL). Furthermore, azide was quantified in plasma (19 µg/mL), serum (24 µg/mL), cell pellet (21 µg/mL) and urine (3.0 µg/mL) of case 2. This method can be used to confirm azide and cyanide exposure, and azide concentrations can be quantified in several biological matrices.