Determination of higher carboxylic acids in snow samples using solid-phase extraction and LC/MS-TOF

Area of Science:

• Environmental Chemistry
• Analytical Chemistry
• Glaciology

Background:

• Higher organic acids are significant components of atmospheric aerosols and precipitation.
• Understanding their presence in snow is crucial for assessing atmospheric deposition and snowpack chemistry.
• Previous methods for analyzing these compounds in snow matrices have limitations.

Purpose of the Study:

• To develop and optimize a robust method for determining higher organic acid concentrations in snow samples.
• To identify and quantify specific dicarboxylic acids, pinonic acid, pinic acid, and phthalic acid.
• To apply the developed method to analyze snow samples from a high-altitude glacier.

Main Methods:

• Solid phase extraction (SPE) was employed for preconcentration of target analytes.
• High-performance liquid chromatography (HPLC) was used for separation of the organic acids.
• Quadrupole time-of-flight mass spectrometry (qTOF-MS) served as the detection technique.
• Optimization of SPE parameters including flow rate and eluent concentration was performed.

Main Results:

• The developed SPE-HPLC-qTOF-MS method demonstrated variable recovery rates (41-102%) for different organic acids.
• Detection limits ranged from 0.9 nmol/L for dodecanedioic acid to 103.9 nmol/L for pinic acid.
• Glutaric acid (C(5)-di), adipic acid (C(6)-di), and phthalic acid (Ph) were quantified in snow samples from Fee glacier, Switzerland.
• Tridecanedioic acid, pinonic acid, and pinic acid were detected but not quantified due to low concentrations.

Conclusions:

• A reliable analytical method was established for the quantification of higher organic acids in snow.
• The study provides valuable data on the occurrence and abundance of specific organic acids in high-altitude snowpack.
• The findings contribute to a better understanding of atmospheric organic acid deposition in remote environments.