Freeze-drying: an alternative method for the analysis of volatile organic compounds in the headspace of urine samples using solid phase micro-extraction coupled to gas chromatography - mass spectrometry.
Freeze-drying: an alternative method for the analysis of volatile organic compounds in the headspace of urine samples using solid phase micro-extraction coupled to gas chromatography - mass spectrometry.
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DOI：
10.1186/s13065-016-0155-2
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发表时间：
2016
影响因子：
--
通讯作者：
Probert CS
中科院分区：
文献类型：
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作者：
Aggio RB;Mayor A;Coyle S;Reade S;Khalid T;Ratcliffe NM;Probert CS
挥发性有机化合物（VOCs）可以是代谢途径的中间体，它们在生物样品中的水平可以提供除了潜在的诊断方法之外的关于疾病的更好的理解。采用固相微萃取（SPME）与气相色谱-质谱（GC-MS）联用技术对尿样中的挥发性有机物进行顶空分析是最常用的技术之一。然而，如果应用于新鲜尿液，它通常会产生有限的VOC分布。为了提高顶空-固相微萃取-气相色谱-质谱联用技术分析尿样中挥发性有机物的准确性，研究了加盐、加碱或加酸等样品前处理方法。这些方法产生更丰富的VOC谱，然而，它们也可能向尿样中添加潜在的污染物，导致手动处理样品引入的可变性增加，并由于极端pH水平而促进代谢物的降解。在这里，我们评估了冷冻干燥是否可以被认为是尿液样品顶空-SPME-GC-MS分析的替代样品制备方法。我们收集了三名志愿者的尿液，并比较了冷冻干燥、加酸（HCl）、加碱（NaOH）、加盐（NaCl）、新鲜尿液和冷冻尿液在鉴定和定量4 ml样本中代谢物时的性能。冷冻干燥和添加酸产生的挥发性有机化合物数量明显高于任何其他方法，冷冻干燥涵盖的化学类别数量略高，显示出改善的可重复性和减少硅氧烷杂质。加强尿液样本的挥发性有机化合物分析。在这项工作中，我们比较了样品制备方法的性能，用于尿样的SPME-GC-MS分析。据我们所知，这是第一项评估冻干作为替代样品制备方法潜力的研究。我们的研究结果表明，冷冻干燥有潜力作为一种替代方法的SPME-GC-MS分析尿样。使用内标物、合成尿液和校准曲线的其他研究将允许更精确地定量代谢物，并对方法进行额外比较。本文的在线版本（doi10.1186/s13065-016-0155-2）包含补充材料，可供授权用户使用。
Volatile organic compounds (VOCs) can be intermediates of metabolic pathways and their levels in biological samples may provide a better understanding about diseases in addition to potential methods for diagnosis. Headspace analysis of VOCs in urine samples using solid phase micro extraction (SPME) coupled to gas chromatography - mass spectrometry (GC-MS) is one of the most used techniques. However, it generally produces a limited profile of VOCs if applied to fresh urine. Sample preparation methods, such as addition of salt, base or acid, have been developed to improve the headspace-SPME-GC-MS analysis of VOCs in urine samples. These methods result in a richer profile of VOCs, however, they may also add potential contaminants to the urine samples, result in increased variability introduced by manually processing the samples and promote degradation of metabolites due to extreme pH levels. Here, we evaluated if freeze-drying can be considered an alternative sample preparation method for headspace-SPME-GC-MS analysis of urine samples. We collected urine from three volunteers and compared the performances of freeze-drying, addition of acid (HCl), addition of base (NaOH), addition of salt (NaCl), fresh urine and frozen urine when identifying and quantifying metabolites in 4 ml samples. Freeze-drying and addition of acid produced a significantly higher number of VOCs identified than any other method, with freeze-drying covering a slightly higher number of chemical classes, showing an improved repeatability and reducing siloxane impurities. Enhancing VOC profiling from urine samples. In this work we compared the performance of sample preparation methods for the SPME-GC-MS analysis of urine samples. To the best of our knowledge, this is the first study evaluating the potential of freeze-dry as an alternative sample preparation method. Our results indicate that freeze-drying has potential to be used as an alternative method for the SPME-GC-MS analysis of urine samples. Additional studies using internal standard, synthetic urine and calibration curves will allow a more precise quantification of metabolites and additional comparisons between methods. The online version of this article (doi10.1186/s13065-016-0155-2) contains supplementary material, which is avaialble to authorize users.