水样过玻璃纤维滤膜后,在滤液中加入适量内标正壬基酚-d₄(4-n-NP-d₄)溶液,使其质量浓度达到10.0 μg·L^-1,涡旋混匀后备用。底泥样品或生物样品的可食部分经除杂、冷冻干燥、研磨后,分取1 g底泥样品或0.2 g生物样品,加入1 000 μg·L^-1 4-n-NP-d₄内标溶液100 μL和甲醇(底泥样品提取溶剂) 5.0 mL或乙腈(生物样品提取溶剂) 5.0 mL,振荡30 s,超声30 min,离心5 min,收集上清液。重复提取一次,合并上清液,并使其中的4-n-NP-d₄质量浓度达到10.0 μg·L^-1。将上述样品溶液引入超高效液相色谱-串联质谱仪,其中的壬基酚聚氧乙烯醚降解产物[壬基酚单乙氧基醚(NP1EO)、壬基酚二乙氧基醚(NP2EO)、对壬基酚(4-NP)和正壬基酚(4-n-NP)]在Shim-pack GIS C₁₈色谱柱上以体积比95∶5的甲醇和1 mmol·L^-1乙酸铵溶液的混合溶液进行等度洗脱分离,以电喷雾离子源负离子(ESI^-)、正离子(ESI⁺)模式分别电离4-NP、4-n-NP、4-n-NP-d₄以及NP1EO、NP2EO,多反应监测(MRM)模式检测,内标法定量。结果显示:标准曲线的线性范围均为1.0~20.0 μg·L^-1,检出限(3S/N)为0.03~0.29 μg·L^-1;按照标准加入法进行回收试验,4-NP、4-n-NP和NP2EO的回收率为70.8%~119%,测定值的相对标准偏差(n=6)为1.5%~8.7%;方法用于50批洛阳江水体样品(水、底泥、海蛏、牡蛎)的分析,水样中4种目标物均未检出,其他3种样品中均未检出4-n-NP,4-NP、NP2EO和NP1EO均有不同程度的检出,且生物样品中这3种目标物的检出量大于底泥中的。

After the water samples were passed through the glass fiber filter membrane, an appropriate amount of 4-n-NP-d₄ internal standard solution was added into the filtrate until its mass concentration reached 10.0 μg·L^-1, and the mixed solution was vortexed for subsequent use. Sediment samples of 1 g or biological samples of 0.2 g after removing impurities, freeze-drying and grinding, together with 100 μL of 1 000 μg·L^-1 4-n-NP-d₄ internal standard solution, and 5.0 mL of methanol (sediment sample extraction solvent) or 5.0 mL of acetonitrile (biological sample extraction solvent) were mixed. The mixture was swirled for 30 s, extracted ultrasonically for 30 min, and centrifuged for 5 min. The extraction process was repeated once, and the supernatant was combined, of which the mass concentration of 4-n-NP-d₄ reached to 10.0 μg·L^-1. The obove solution was introduced into ultra-high performance liquid chromatograph-tandem mass spectrometer. Four degradation products of nonylphenol ethoxylate (NP1EO, NP2EO, 4-NP and 4-n-NP) were separated on the Shim-pack GIS C₁₈ column with mixed solutions composed of methanol and 1 mmol·L^-1 ammonium acetate solution at volume ratio of 95∶5 by isocratic elution, ionized by ESI^- mode (4-NP, 4-n-NP and 4-n-NP-d₄) and ESI⁺ mode (NP1EO and NP2EO), detected by MRM mode, and quantified by internal standard method. As shown by the results, linear ranges of standard curves were in the range of 1.0-20.0 μg·L^-1, with detection limits (3S/N) in the range of 0.03-0.29 μg·L^-1. Test for recovery was made by standard addition method, giving results in the range of 70.8%-119%, and RSDs (n=6) of the determined values ranged from 1.5% to 8.7%. The proposed method was applied to the analysis of 50 samples of water, sediment, oyster and razor clam in Luoyang River water body, 4 targets were not detected in water sample, 4-n-NP was not detected in sediment and biological samples, while 4-NP、NP2EO and NP1EO could be detected to varying degrees, with detection amounts of the 3 targets in biological samples greater than those in sediment samples.