建立了一种结合不同色谱及质谱技术测定饲料中黄霉素总残留量的方法.通过高效液相色谱对黄霉素标准混合物进行有效分离,结合液相色谱—串联质谱对黄霉素A化合物进行定量,并利用高分辨四极杆飞行时间质谱确定结果的准确性和唯一性,最终基于面积归一化法得出精确结果.黄霉素标准品经Platisil 5 µm ODS色谱柱(250.0 mm ×4.6 mm,5μm),以乙腈和20 mmol/L(pH 5.0)乙酸铵溶液为流动相进行等度分离.同时,饲料基质经体积分数0.1%甲酸甲醇溶液提取,采用Oasis PRiME HLB通过式固相萃取对提取液进行净化.目标物经Atiantis® T3色谱柱(100.0 mm ×2.1 mm,3 μm),以乙腈和5 mmol/L(pH 5.0)乙酸铵溶液为流动相进行梯度分离,在负离子(ESI-)多反应监测(MRM)模式下进行定量分析.考查了不同高效液相色谱条件对黄霉素5种活性成分分离效果的影响,同时研究了不同提取溶剂和净化方式对黄霉素A化合物回收率的作用并优化其质谱条件.所建立的方法确保黄霉素5种活性成分完全分离,面积归一化法结果表明黄霉素A所占黄霉素混合物的比例为86.2%,RSD为0.66%.同时,该方法确保黄霉素A在10.0~1 000.0 ng/mL范围内线性关系良好,线性相关系数(R2)大于等于0.998 6.不同饲料基质中黄霉素A的低、中、高加标回收率为69.69%~88.60%,RSD为0.96%~3.38%,回收率稳定、重现性良好.经折算,各类饲料基质中,黄霉素抗生素的总加标回收率为80.66%~102.55%.统计结果表明,所建立的方法普适性广,准确性强,灵敏度高,适用于饲料中黄霉素总残留量的精确定量分析,解决了国内外对黄霉素检测不准确的技术问题.
Study on Determination of Total Flavomycin in Feedstuff Based on Area Normalization Method
A combined method for the determination of flavomycin residue in feedstuff by chromatographic and mass spectrometry technology was established.The standard mixture of flavomycin was effectively separated by high-performance liquid chromatography,and moenomycin A was quantified by liquid chromatography-tandem mass spec-trometry.The accuracy and uniqueness of the results were determined by high resolution quadrupole time-of-flight mass spectrometry.Finally,the precise results were obtained by area normalization method.The flavomycin mixture standard was performed on Platisil 5 μm ODS column(250.0 mm ×4.6 mm,5 μm)with acetonitrile and 20 mmol/L ammonium acetate(pH 5.0)as the LC mobile phase.The feedstuff matrixes were extracted by methanol containing 0.1%(V/V)formic acid and cleaned by use of the Oasis PRiME HLB SPE system.The residue targets were a-chieved on Atiantis® T3 column(100.0 mm ×2.1 mm,3 μm)with the same gradient elution of 5 mmol/L ammoni-um acetate(pH 5.0)and acetonitrile as mobile phases and detected by LC-MS/MS with MRM mode via ESI-ion-ization.The various chromatographic condition,extracting solvent and purification method were optimized to promote the target recoveries.Those five essential components of flavomycin had been separated and moenomycin A had been obviously located.The proposition of moenomycin A could be calculated as 86.2%with the RSD as 0.66%via area normalization method.Moenomycin A showed good linear ranged from 10.0 ng/mL to 1 000.0 ng/mL by various ma-trix curves,while the coefficients(R2)were all higher than 0.998 6.The average recoveries on three spiked level(low,medium,high)for moenomycin A ranged from 69.69%to 88.60%,with RSD from 0.96%to 3.38%,ex-hibiting satisfying recoveries and stable repeatability.Thus,the recoveries of total flavomycin were converted from 80.66%to 102.55%in feedstuff matrixes.This combined method,having great accuracy and high sensitivity,can be suitably employed on the determination of flavomycin in feedstuff products,and can solve the technical barrier of inaccurate detection on flavomycin in domestic and international fields of feedstuff.