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Obter orçamento

Determination of carbonyl impurities, such as aldehydes and ketones, in alcoholic organic solvents is essential for ensuring product quality and stability.

This Application Note describes a polarographic method that employs the Multi-Mode Electrode pro for the simultaneous determination of different carbonyl compounds in alcohols. It offers a simple and sensitive tool for industries requiring rigorous alcohol quality control.

This technique involves the formation of hydrazone derivatives through the reaction of carbonyl compounds with hydrazine sulfate. Its advantage lies in its multi-analyte determination, detection of low-concentration carbonyl compounds and applicability to a broad range of alcohols, e.g., methanol or propanol, enabling precise quality assessments.

Methanol
Isopropanol

884 Professional VA manual for MME
Figure 1. 884 Professional VA manual for MME

Add ultrapure water, the sample, and electrolyte solution into the measuring vessel and degas it for 5 min. Determination is carried out with the 884 Professional VA manual for MME (Figure 1) using parameters listed in Table 1. Quantification is done using two standard additions with respective standard addition solutions.

Table 1. Parameters
Parameter Setting
Mode DME
Start potential -0.8 V
End potential -1.6 V
Sweep rate 20 mV/s
Peak potential acetaldehyde -1.22 V
Peak potential formaldehyde -1.08 V
Peak potential acetone -1.38 V
Peak potential propionaldehyde -1.22 V
  • Multi-Mode Electrode pro
Determination of formaldehyde, acetaldehyde, and acetone in methanol
Figure 2. Determination of formaldehyde, acetaldehyde, and acetone in methanol

Figure 2 shows the results of formaldehyde, acetaldehyde, and acetone determination in methanol.

Determination of propionaldehyde and acetone in isopropanol
Figure 3. Determination of propionaldehyde and acetone in isopropanol

Figure 3 shows the results of propionaldehyde and acetone determination in isopropanol.

Table 2. Result
Analyte Methanol Isopropanol
β(Formaldehyde) mg/L 8.22 -
β(Acetaldehyde) mg/L 7.08 -
β(Propionaldehyde) mg/L - 5.95
β(Acetone) mg/L 45.21 4.02
Contato

Metrohm Brasil

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05007-030 São Paulo

Contato

Internal references: AW VA CH4-0634-042024