Study On Detection Techniques Of Hazardous Chemical Substances In Drinking Water And Children’s Products

Water is the source of life,and human health is closely related to the quality and safety of drinking water.Chemical hazards that may be present in drinking water and have an important impact on water quality.For example,trace amounts of nitrosamines that may be produced by chlorination are highly toxic and are referred to by the media as “PM 2.5 in water”.Children’s products such as toys have gradually become the necessity for children,but some harmful chemicals such as nitrosamines,fragrance allergens,etc.may be left in the process of production and storage.They would be orally,percutaneously or inhaled when children played.Migrate to children and cause damage to their health.Developed countries such as the European Union and the United States have established strict regulations for nitrosamines and fragrance allergens.This paper aims to establish a rapid,accurate and sensitive detection method for nitrosamines and fragrance allergens in drinking water and children’s products,and provide technical support for the quality and safety of drinking water and children’s products.The specific research contents are as follows:(1)Based on solid phase extraction-gas chromatography-electrostatic field orbitrap high resolution mass spectrometry,a method for the determination of sixteen trace nitrosamines in drinking water was established.High-resolution full-scan mode detection was used,and internal standard method was used for quantification.Firstly,the chromatographic and mass spectrometry conditions were optimized to obtain higher detection sensitivity.The optimal condition was as follows: ion source temperature 280℃,carrier gas flow 2.0 m L/min,surge splitless injection and surge pressure 200 k Pa.Then orthogonal experiments were designed to obtain the optimal solid phase extraction condition: Chromabond HR-P solid phase extraction column,10 m L ethyl acetate elution.The results showed that the correlation coefficient of sixteen nitrosamines were more than 0.9943 in the linear range from 0.2 to500 μg/L,and the detection limits ranged from 0.05 to 0.5 ng/L.The recovery rates were between 72.4% and 114.8%,and the relative standard deviations(RSD)were less than 9.5%.Finally,twelve water samples from different parts of Beijing were measured and nitrosamines were detected ranged from0.9 to 20.4 ng/L.The method has high sensitivity and accuracy and is suitable for the detection of trace nitrosamines in water.(2)Based on solid phase extraction-gas chromatography-electrostatic field orbitrap high resolution mass spectrometry,the determination method of sixteen nitrosamines and their precursors in children’s products was further established.The optimal solid phase extraction condition was obtained by orthogonal experiment: Chromabond HR-P solid phase extraction column(350 mg)and 10 m L of ethyl acetate.The results of variance analysis showed that the type of solid phase extraction column had a significant effect on the solid phase extraction process,and its interaction with the elution solvent also had a very significant effect.The correlation coefficients of each substance were more than 0.9945 with ranged from 0.2 to 500 μg/L,and the detection limits ranged from 0.03 to 0.38 μg/kg.The recoveries were between 85.7%and 101.5%,and the RSDs were less than 9.9%.Finally,various types of children’s products were tested,with high detection rates of NDMA,NMPh A and NDBz A.This method has high sensitivity and good selectivity,and is suitable for detecting the migration of nitrosamines and their precursors in children’s products.(3)Based on headspace-gas chromatography-quadrupole mass spectrometry,a method for the determination of forty-eight fragrance allergens in wooden children’s products was established.Firstly,the optimal headspace condition was obtained by single factor experiment and response surface experiment: equilibrium temperature 200℃,equilibrium time 35 min,auxiliary gas pressure 78 k Pa.The limit of quantification ranged from 0.02 to20 mg/kg,and the correlation coefficients were more than 0.9919 with ranged from 0.2 to 1000 mg/kg.The recovery rates of majority substance ranged from 79.8% to 115.2%,with RSD less than 9.9%,without apparent matrixeffect.Finally,thirty wooden samples were tested and different levels of allergens were detected.Among them,the detection rates of benzyl alcohol,eugenol and isoeugenol were higher.The method is simple and rapid,and is suitable for the determination of fragrance allergens in wooden children’s products.