确定颗粒物中的重金属

Primary particulate matter is generated from various sources. A part of the air pollution caused by particulate matter has anthropogenic origin and occurs not only due to the burning of fossil fuels and wood, but also due to swirling and abrasion. Particulate matter pollution can also be caused due to natural sources such as sea spray, erosion, volcanic eruptions, and desert dust (Figure 1).

图1。颗粒物的来源：工业，燃烧木材和化石燃料，火山喷发，海洋喷雾，沙漠灰尘和侵蚀。

Chemical reactions involving materials of agricultural origin, e.g. SO_X，NH₃， 不_X, volatile organic compounds, and waste gases released from combustion processes lead to the formation of secondary particulate matter in the atmosphere. When we inhale air, innumerable airborne particles enter our body, and based on their sizes, they may be deposited in the respiratory tract or in the gas exchange zone (the pulmonary alveoli).

粒度

直径小于10 µm的颗粒的混yabo214合物称为颗粒物或PM₁₀（即胸尘）。这些颗粒是如此yabo214之小，以至于它们可以通过风管轻松进入肺部。同样，直径小于1和2.5 µm的灰尘颗粒的混合物被称为PMyabo214₁和下午_2.5（即可吸入的灰尘）。直径小于0.yabo2141 µm的灰尘颗粒称为超细颗粒。

Sampling

Conventional sampling systems are equipped with filters to collect particulate matter from the air as well as dust precipitation that settles on the ground. The collected particulate matter is dissolved using acid digestion. However, this technique is highly time-consuming, and can also result in inaccurate analysis results as a result of contamination.

还有其他可用的采样系统可以克服此类缺点，被认为是过滤技术的可行替代方案。粒子 - 液体采样器，或PIL（图2），可以将气溶胶并因此将颗粒直接转移到水溶液中。yabo214收集过程大约需要15分钟，以确保为伏安分析提供足够的样品解决方案。

获得的测量解决方案可以转移到分析仪上进行伏安法或离子 - 色谱测定，而无需其他样品制备步骤。该过程中涉及的半连续测量能够确定具有较高时间分辨率的阴离子和阳离子，从而可以跟踪气溶胶组成的快速变化。

图2。The PILS (Particle-Into-Liquid Sampler) transfers aerosols, and therefore also particles, directly into an aqueous sample solution that can be analyzed voltammetrically by a 797 VA Computrace without any further sample preparation steps needed.

通过使用上游分离器（旋风，撞击器）yabo214，可以限于要分析的颗粒大小的直径小于1、2.5或10 µm。PIL可以直接传递各种尺寸的颗粒（从PM发出yabo214₁到下午₁₀₎into the aqueous sample solution.

PILS采样系统的示意图

环境空气由真空泵以1 m的速度绘制³/h并通过由PILS中的超纯水产生的过饱和蒸汽运输。如图3所示，在蒸汽气氛中，气溶胶颗粒发育成液滴，并在末端由撞击板收集。yabo214结果，可以在短时间内产生足够的样品解决方案进行后续分析。

图3。PILS采样系统的示意图。

The PILS can be combined with a voltammetric measuring system, such as the 797 VA Computrace (Figure 4), to quantify heavy metals such as cadmium, zinc, lead, copper, cobalt, nickel, and so on (Figure 5) in particulate matter at a temporal resolution of nearly 30 minutes.

Figure 4.797 VA Computrace。

Figure 5.在PILS采样系统的帮助下，在环境空气中重量金属浓度（CD，PB和CU）的半连续伏安测定。

在环境空气中测量镉，铅和铜的示例

For the given example, the heavy metal concentration in the ambient air was continuously monitored for three days. Once the sample was generated using皮尔斯，通过伏安测定重金属，例如铜，铅和镉等重金属的浓度。清楚地表明，重金属浓度稳定增加。随着雨水咒语清洁环境空气，测得的铜和铅的浓度明显下降。

This information has been sourced, reviewed and adapted from materials provided by Metrohm AG.

有关此消息来源的更多信息，请访问Metrohm Ag。