Picó Yolanda, la Farré Marinel, Soler Carla, Barceló Damià
Laboratori de Bromatologia i Toxicologia, Facultat de Farmàcia, Universitat de València, Av. Vicent Andrés Estellés s/n, 46100 Burjassot, Valencia, Spain.
J Chromatogr A. 2007 Dec 28;1176(1-2):123-34. doi: 10.1016/j.chroma.2007.10.071. Epub 2007 Oct 30.
Ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QqTOF-MS) is an emerging technique offering more rapid and efficient separation, as well as the possibility to obtain accurate mass measurement and tandem mass spectrometry (MS/MS). This paper deals with the use of UPLC-QqTOF-MS to identify the pesticide residues present in complex pear extracts. Carbendazim, imazalil, and ethoxyquin were successfully identified because of the accurate mass determination of their protonated molecule and their major fragments in the product ion mass spectra. A few plastic and latex additives were also found, most of them probably coming from the packaging transfer to the fruits. The potential of the UPLC-QqTOF-MS and UPLC-QqTOF-MS/MS techniques as a quantification tool is also discussed taking imazalil as example. For quantification, calibration curves were linear over a dynamic range of 2 orders of magnitude, whereas higher calibration ranges are better adjusted to polynomial curves of second and third order. Quantification using different mass windows was also assessed. Accurate quantification required mass windows as wide as 20 mDa, narrower mass windows of 5 mDa provided erroneous quantification, probably because the low ion abundance. The mean recoveries and percentage relative standard deviation (RSD) of 35 determinations for imazalil were 76% (13% RSD) by MS and 77% (14% RSD) by MS/MS. The theoretical limit of detection was 0.4 microg kg(-1), with a validated limit of quantification of 2 microg kg(-1). The quantitative data obtained using UPLC-QqTOF-MS were compared with those obtained using conventional liquid chromatography (LC)-MS/MS with a triple quadrupole (QqQ). It was concluded that UPLC-QqTOF-MS might become a powerful analytical tool for both, unknown's identification and quantification of target pesticides.
超高效液相色谱-四极杆飞行时间质谱联用仪（UPLC-QqTOF-MS）是一种新兴技术，它能实现更快速、高效的分离，还具备获得精确质量测量和串联质谱（MS/MS）的能力。本文探讨了使用UPLC-QqTOF-MS来鉴定复杂梨提取物中存在的农药残留。多菌灵、抑霉唑和乙氧基喹啉因在产物离子质谱图中其质子化分子及其主要碎片的精确质量测定而被成功鉴定。还发现了一些塑料和乳胶添加剂，其中大多数可能是从包装转移到水果上的。本文还以抑霉唑为例，讨论了UPLC-QqTOF-MS和UPLC-QqTOF-MS/MS技术作为定量工具的潜力。对于定量分析，校准曲线在2个数量级的动态范围内呈线性，而更高的校准范围则能更好地拟合二阶和三阶多项式曲线。还评估了使用不同质量窗口进行定量的情况。准确的定量分析需要20 mDa宽的质量窗口，5 mDa的较窄质量窗口会导致定量错误，这可能是由于离子丰度较低。抑霉唑35次测定的平均回收率和相对标准偏差（RSD）分别为：质谱法为76%（RSD为13%），串联质谱法为77%（RSD为14%）。理论检测限为0.4 μg kg⁻¹，验证后的定量限为2 μg kg⁻¹。将使用UPLC-QqTOF-MS获得的定量数据与使用配备三重四极杆（QqQ）的传统液相色谱（LC）-MS/MS获得的数据进行了比较。得出的结论是，UPLC-QqTOF-MS可能成为鉴定未知物和定量目标农药的强大分析工具。
