National Institute of Water and Atmospheric Research, PO Box 14-901, Kilbirnie, Wellington, 6241, New Zealand.
Dep. of Soil and Physical Sciences, Lincoln Univ., PO Box 84, Lincoln, 7647, New Zealand.
J Environ Qual. 2020 Sep;49(5):1110-1125. doi: 10.1002/jeq2.20129. Epub 2020 Aug 26.
Certain aspects in the collection, handling, storage, and subsequent analysis of discrete air samples from non-steady-state flux chambers are critical to generating accurate and unbiased estimates of nitrous oxide (N O) fluxes. The focus of this paper is on air sample collection and storage in small vials (<12 ml) primarily for gas chromatography (GC) analysis. Sample integrity is assured through following simple procedures including storage under pressure and analysis within a few months of collection. Concurrent storage of standards in an identical manner to samples is recommended and allows the storage period to be reliably extended. In the laboratory, an autosampler is typically used in batch analysis of ∼200 sequentially analyzed samples by GC with an electron capture detector (ECD). Some comparisons are given between GC and alternatives including optical N O detectors that are increasingly being used for high-precision N O measurement. The importance of calibration and traceability of gas standards is discussed, where high-quality standards ensure the most accurate assessment of N O concentration and comparability between laboratories. The calibration allows a consistent and best estimate of flux to be derived.
从非稳态通量室中采集、处理、储存离散空气样本的某些方面对于生成准确和无偏的氧化亚氮（N2O）通量估算至关重要。本文的重点是在小瓶（<12ml）中收集和储存空气样本，主要用于气相色谱（GC）分析。通过遵循简单的程序，包括在收集后几个月内进行压力储存和分析，可以确保样本的完整性。建议以与样品相同的方式同时储存标准品，从而可以可靠地延长储存期。在实验室中，通常使用自动进样器在气相色谱仪（GC）上分批分析约 200 个顺序分析的样品，使用电子俘获检测器（ECD）。对 GC 与包括越来越多地用于高精度 N2O 测量的光学 N2O 探测器等替代方法进行了一些比较。讨论了气体标准品的校准和可追溯性的重要性，高质量的标准品可确保最准确地评估 N2O 浓度以及实验室之间的可比性。校准可以得出一致且最佳的通量估算值。
