Identifying Aldehydes, Ketones via Automated Desorption

Aldehydes and ketones are found in many products, and their use in the chemical industry is widespread. For example, formaldehyde is used for producing particle boards, plywood and other glued woods, as well as synthetic resins, while acetaldehyde and ketones are used as organic solvents to produce many products, including indoor building materials.

However, volatile aldehydes and ketones are also known carcinogens and can cause other health problems. A number of methods are available to determine the existence and concentration of these organic compounds. These procedures are based on sampling air samples, in which analytes react with 2,4-dinitrophenylhydrazine (DNPH) to form hydrazones, which are eluted and identified using HPLC and UV detection. However, none of these procedures are fully automated, lengthening the time to results and possibly introducing processing errors.

A team of GERSTEL scientists developed a simple procedure to fully automate the identification process from desorption of bound DNPH analytes through HPLC separation and analysis. The scientists took 15 stock solutions of compounds (adetaldehyde, acetone, acrolein, benzaldehyde, n-butyraldehyde, crotonaldeyde, 2,5-dimethylbenzaldehyde, formaldehyde, hexaldehyde, isovaleraldehyde, propionaldehyde, m-, o-, and p-tolualdehyde, and valeraldehyde), and tested a constructed test chamber made of plywood as well as the interior air of a 2015 model automobile.

Air samples were taken using the GERSTEL GSS sampler, with transport adapters added to the ports on top of the cartridges to allow solvent delivery and collection. Automated desorption of DNPH samples was performed with the dual-head GERSTEL MultiPurpose Sampler (MPS), configured with an Anatune automated DNPH unit. Sample injections were performed using the MPS. Desorption was controlled, and subsequent HPLC and mass spectrometry results analyzed using MAESTRO software.

Air samples were reliably collected using the GSS sampler, and linear calibration curves with R2 values of 0.99 or greater were obtained based on injection of calibration standards. Formaldehyde was the most prevalent compound throughout all test samples. The researchers also found additional aldehyde and ketone DNPH-derivatives from the plywood and car interior air samples.

You can read the application note, “Automated Online Desorption and Analysis of DNPH Derivatives and Airborne Aldehydes and Ketones” by clicking here.

After reading the details, feel free to reach out to us for a deeper conversation about automating the desorption and analysis of DNPH-derivatives and other volatile organic compounds in your laboratory.