Determination of N-nitrosamines in Water by Automated Headspace Solid-Phase Microextraction

Traditional methods and biosensors for detecting disinfection by-products in water: A review

In recent years, pollution caused by disinfection by-products (DBPs) has become a global concern. Initially, there were fewer contaminants, and the mechanism of their generation was unclear; however, the number of contaminants has increased exponentially as a result of rapid industrialization and numerous economic activities (e.q., during the outbreak of COVID-19 a surge in the use of chlorinated disinfectants was observed). DBP toxicity results in various adverse health effects and organ failure in humans. In addition, it profoundly affects other forms of life, including animals, plants, and microorganisms. This review comprehensively discusses the pre-treatment methods of traditional and emerging DBPs and the technologies applied for their detection. Additionally, this paper provides a detailed discussion of the principles, applicability, and characteristics of traditional large-scale instrumentation methods (such as gas/liquid/ion chromatography coupled with mass spectrometry) for detecting DBPs based on their respective detection techniques. At the same time, the design, functionality, classification, and characteristics of rapid detection technologies (such as biosensors) are also detailed and analyzed.

New and efficient direct-SLM two-phase hollow fiber electromembrane extraction coupled to GC/MS for the analysis of nitrosamines in different types of sausage: Investigation of meat type, meat percent and cooking methods

The potent two-phase hollow fiber electromembrane extraction technique coupled to gas chromatography mass spectrometry (HF-EME/GC-MS) was proposed for the determination of six types of carcinogen nitrosamines in sausages samples. Two steps of sample digestion were accomplished for the complete removal of fat globules and efficient release of target analytes. The extraction principle was based on electro-migration of target analytes via specific fiber to extraction solvent. 2-Nitrophenyl octyl ether (NPOE) was dexterously employed as both supported liquid membrane and extraction solvent, which is compatible with GC-MS. After the extraction process, the NPOE containing nitrosamines was directly injected to GC-MS without extra steps requirement to reduce analysis time. The consequences revealed that N-nitrosodiethylamine (NDEA) as the most potent carcinogen has the highest concentration in fried and oven-cooked sausages with 70% of red meat. The meat type and amount and also cooking process could significantly effect on nitrosamines formation.

Simultaneous Determination for Nine Kinds of N-Nitrosamines Compounds in Groundwater by Ultra-High-Performance Liquid Chromatography Coupled with Triple Quadrupole Mass Spectrometry

The ability to effectively detect N-nitrosamine compounds by liquid chromatography-tandem mass spectrometry presents a challenge due to the problems of high detection limits and difficulty in simultaneous N-nitrosamine compound detection. In order to overcome these limitations, this study reduced the detection limit of N-nitrosamine compounds by applying n-hexane pre-treatment to remove non-polar impurities before the conventional process of column extraction. In addition, ammonium acetate was used as the mobile phase to enhance the retention of nitrosamine target substances on the chromatographic column, with formic acid added to the mobile phase to improve the ionization level of N-nitrosodiphenylamine, to achieve the simultaneous detection of multiple N-nitrosamine compounds. Applying these modifications to the established detection method allowed the rapid and accurate detection of N-nitrosamine in water within 12 min. The linear relationship, detection limit, quantification limit and sample spiked recovery rate of nine types of nitrosamine compound were investigated, showing that the correlation coefficient ranged from 0.9985-0.9999, while the detection limits of the instrument and the method were 0.280-0.928 µg·L^-1 and 1.12-3.71 ng·L^-1, respectively. The spiked sample recovery rate ranged from 64.2-83.0%, with a standard deviation of 2.07-8.52%, meeting the requirements for trace analysis. The method was applied to the detection of N-nitrosamine compounds in nine groundwater samples in Wuhan, China, and showed that the concentrations of N-nitrosodimethylamine and NDEA were relatively high, highlighting the need to monitor water bodies with very low levels of pollutants and identify those requiring treatment.