WALL-E/Vocus AIM data: Online particle phase chemical composition

The spontaneous formation of OH radicals at the air-water interfaces of organic droplets was invstigated. In our study, we performed on line particle phase size resolved measurements, aiming to understand whether or not the oxidation process depends on the size of the particles. The on line measurements were performed using the WALL-E (wall free particle evaporator) particle phase inlet coupled with a Vocus AIM (adduct ionization mechanism) high resolution mass spectrometer. For the experiments of this study, iodide (I – ) was selected as the reagent ion, as it is suitable for the detection of carboxylic acids. We monitored the signal of the studied organic compounds (reactants) i.e., citric, maleic and aconitic acid as a function of particle size, as well as the signals of the generated products.As final oxidation products we identified a) Citric acid + OH: malonic, malic, hydroxy maleic and oxyglutaric acids, and C5H6O6, b) Maleic acid + OH: malic and acrylic acids and c) Aconiti..., , # WALL-E/Vocus AIM data: Online particle phase chemical composition

Dataset DOI: [10.5061/dryad.6q573n68z](10.5061/dryad.6q573n68z)

## Description of the data and file structure

We upload .txt files with the detected masses and the raw signals that led to the quantification of the product formation yields as a function of time (given in minutes).

All data (txt format) contain the raw signals of the detected products (formula included) and the reactants, during the reaction of citric, maleic and aconitic acid with OH radicals. Water and iodide (reagent ion) signal are also given as they used for the normalisation of the data. The name of the files contains the type of acid and the number of experiment.

### Files and variables

#### File: Aconitic\_acid\_exp1.txt

**Description:** Aconitic acid particles at various sizes + OH radicals formed via water vapour (1st measurement)

##### Variables

* C4H4IO5: Oxalaxetic/hydroxymaleic acid raw signal
* C4H6IO5: Malic acid raw signal
* C5H6...,

本研究针对有机液滴气-水界面处羟基自由基（OH radicals）的自发生成过程展开探究。本实验采用在线颗粒相粒径分辨测量手段，旨在明确氧化过程是否与颗粒粒径存在关联。本次在线测量依托搭载Vocus AIM（adduct ionization mechanism，加合离子化机制）高分辨率质谱仪的WALL-E（wall free particle evaporator，无壁颗粒蒸发器）颗粒相进样系统完成。本实验选用碘离子（I⁻）作为试剂离子，因其适用于羧酸类化合物的检测。我们监测了目标有机反应物（即柠檬酸、马来酸与乌头酸）的信号随颗粒粒径的变化情况，同时同步监测了反应生成产物的信号。经鉴定，最终氧化产物如下：a) 柠檬酸与OH自由基反应产物：丙二酸、苹果酸、羟基马来酸及氧代戊二酸，以及C5H6O6；b) 马来酸与OH自由基反应产物：苹果酸与丙烯酸；c) 乌头酸……
# WALL-E/Vocus AIM 数据集：在线颗粒相化学组成
数据集DOI：10.5061/dryad.6q573n68z

## 数据与文件结构说明
本数据集上传了包含检测质荷比与原始信号的TXT文件，相关数据用于定量解析产物生成产率随时间（单位：分钟）的变化规律。
所有TXT格式数据均包含柠檬酸、马来酸与乌头酸与OH自由基反应过程中，检测到的产物（含分子式）与反应物的原始信号。同时文件中也包含水与试剂离子碘离子的信号，用于数据的归一化处理。文件名包含所使用的酸类名称与实验编号信息。

### 文件与变量

#### 文件：Aconitic_acid_exp1.txt

**说明：** 不同粒径的乌头酸颗粒与通过水蒸气生成的OH自由基的反应实验（首次测量）

##### 变量
* C4H4IO5：草酰乙酸/羟基马来酸原始信号
* C4H6IO5：苹果酸原始信号
* C5H6……