顶空固相微萃取-气相色谱三重四极杆串联质谱同时测定饮用水中9种嗅味物质

针对新国标背景下饮用水不同异味类型致嗅物的同时检测需求，建立了基于顶空固相微萃取与气相色谱三重四极杆串联质谱联用的内标法同时测定9种关键致嗅物的分析方法。分析了萃取纤维类型、盐浓度、萃取温度、萃取和解析时间等条件对萃取效果的影响，优化后的测试条件为：使用CAR/PDMS-85 μm萃取纤维，氯化钠投加量为3 g，内标浓度为100 ng·L⁻¹，将10 mL水样于65 ℃条件下萃取30 min，250 ℃条件下解析300 s。该方法9种嗅味物质的标准曲线具有良好的线性 (R² >0.995) ，检出限为0.2~1.5 ng·L⁻¹，在超纯水、自来水和水源水中的加标回收率分别为84.0%~115% (10 ng·L⁻¹) 、80.5%~112% (50 ng·L⁻¹) 、88.8%~111% (250 ng·L⁻¹) ，相对标准偏差小于16%，满足样品定量分析要求。采用优化后的方法测定南方某水库水样，二甲基二硫醚 (12.1~41.6 ng·L⁻¹) 、二甲基三硫醚 (9.9~11.6 ng·L⁻¹) 、β-环柠檬醛 (5.8~13.1 ng·L⁻¹) 、2-甲基异莰醇 (11.1~25.3 ng·L⁻¹) 和土臭素 (5.6~8.7 ng·L⁻¹) 均有检出。

Simultaneous quantification of 9 odorants in drinking water by headspace solid-phase microextraction coupled with gas chromatography-triple quadrupole tandem mass spectrometry

In response to the implementation of the new national drinking water quality standard in China, an internal standard method based on headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-triple quadrupole tandem mass spectrometry (GC-MS/MS) was developed for the simultaneous determination of nine typical odorants in water, including 2-methylisoborneol, and dimethyl disulfide. The effects of extraction fiber type, salt concentration, extraction temperature, extraction and resolution time on the extraction efficiencies were analyzed. The optimized HS-SPME procedures were as follows: CAR/PDMS-85 μm fiber was used to extract odorants. After adding 3 g NaCl, the extraction of 10 mL water sample with 100 ng·L−1 internal standard was carried out at 65 ℃ for 30 min, and the resolution was carried out at 250 ℃ for 300 s. The standard curves of nine odorants had good linearity (R2 >0.995) under the optimized conditions, and the detection limits ranged from 0.2 to 1.5 ng·L−1. The spiked recoveries in ultrapure water, tap water, and source water were 84.0%~115% (10 ng·L−1), 80.5%~112% (50 ng·L−1), and 88.8%~111% (250 ng·L−1), respectively, with relative standard deviations (RSD) less than 16%, which meeted the requirements of quantitative analysis of water samples. The optimized method was used to determine odorant concentration in water samples collected from a reservoir in southern China. Dimethyl disulfide (12.1~41.6 ng·L−1), dimethyl trisulfide (9.9~11.6 ng·L−1), β-cyclocitral (5.8~13.1 ng·L−1), 2-methylisocamphol (11.1~25.3 ng·L−1) and geosmin (5.6~8.7 ng·L−1) were detected.