Eiguren Fernandez Arantzazu, Lewis Gregory S, Spielman Steven R, Hering Susanne V
Aerosol Dynamics Inc., 935 Grayson St., Berkeley, CA, phone: +1 (510) 649-9360, fax: +1 (510) 649-9361.
Atmos Environ (1994). 2014 Oct 1;96:125-134. doi: 10.1016/j.atmosenv.2014.07.031.
A versatile and compact sampling system, the Sequential Spot Sampler (S3) has been developed for pre-concentrated, time-resolved, dry collection of fine and ultrafine particles. Using a temperature-moderated laminar flow water condensation method, ambient particles as small as 6 nm are deposited within a dry, 1-mm diameter spot. Sequential samples are collected on a multiwell plate. Chemical analyses are laboratory-based, but automated. The sample preparation, extraction and chemical analysis steps are all handled through a commercially-available, needle-based autosampler coupled to a liquid chromatography system. This automation is enabled by the small deposition area of the collection. The entire sample is extracted into 50-100μl volume of solvent, providing quantifiable samples with small collected air volumes. A pair of S3 units was deployed in Stockton (CA) from November 2011 to February 2012. PM samples were collected every 12 hrs, and analyzed for polycyclic aromatic hydrocarbons (PAHs). In parallel, conventional filter samples were collected for 48 hrs and used to assess the new system's performance. An automated sample preparation and extraction was developed for samples collected using the S3. Collocated data from the two sequential spot samplers were highly correlated for all measured compounds, with a regression slope of 1.1 and r=0.9 for all measured concentrations. S3/filter ratios for the mean concentration of each individual PAH vary between 0.82 and 1.33, with the larger variability observed for the semivolatile components. Ratio for total PAH concentrations was 1.08. Total PAH concentrations showed similar temporal trend as ambient PM concentrations. Source apportionment analysis estimated a significant contribution of biomass burning to ambient PAH concentrations during winter.
顺序点滴采样器（S3）是一种多功能紧凑型采样系统，专为预浓缩、时间分辨、干式收集细颗粒和超细颗粒而开发。采用温度调节的层流水冷凝方法，直径小至6纳米的环境颗粒会沉积在一个干燥的、直径为1毫米的点内。顺序样本收集在多孔板上。化学分析基于实验室，但实现了自动化。样品制备、提取和化学分析步骤均通过与液相色谱系统相连的商用针式自动进样器进行处理。这种自动化得益于收集的沉积面积小。整个样品被提取到50 - 100微升体积的溶剂中，以小的采集空气体积提供可量化的样品。2011年11月至2012年2月，在加利福尼亚州斯托克顿部署了一对S3装置。每12小时收集一次PM样本，并分析其中的多环芳烃（PAHs）。同时，收集传统滤膜样本48小时，用于评估新系统的性能。针对使用S3收集的样本开发了自动样品制备和提取方法。两个顺序点滴采样器的并置数据对于所有测量的化合物都具有高度相关性，所有测量浓度的回归斜率为1.1，r = 0.9。每种单独PAH平均浓度的S3/滤膜比值在0.82至1.33之间变化，半挥发性成分的变化更大。总PAH浓度的比值为1.08。总PAH浓度显示出与环境PM浓度相似的时间趋势。源解析分析估计冬季生物质燃烧对环境PAH浓度有显著贡献。
