Sample Preparation of PET Preforms for volatile Formaldehyde

Sample Preparation of PET Preforms for volatile Formaldehyde

Formaldehyde is volatile. Avoid evaporation during sample prep with Retsch’s cryogenic grinding at – 196 °C.

The beverage industry tests plastic bottles for formaldehyde as part of their quality control process. This is usually performed on the preforms for the beverage bottles.

Before the actual analysis can be done, the formaldehyde must be extracted from a sample. To do this reproducibly, the sample first has to be comminuted.

Because formaldehyde is a volatile substance, the mechanical energy input which is necessary for the grinding process can lead to its evaporation. To avoid this effect, cryogenic grinding is the method of choice. The first step, however, is the short and gentle preliminary grinding of the preforms in a cutting mill, such as RETSCH’s SM 100, with a bottom sieve of 6 mm. The obtained granules are then pulverised in the RETSCH CryoMill at – 196 °C with liquid nitrogen. The cooling ensures that the sample does not warm up during grinding, thus preserving the formaldehyde. Moreover, the sample is embrittled which improves the milling process. The CryoMill quickly grinds the preforms down to a powder of 100 microns and less which can then be used for extraction of the formaldehyde. The actual spectroscopic analysis is carried out by colour reaction (e.g. with MBTH or Schiff test).

Questions? Contact us

    Metrohm Australia/New Zealand

    Please select your topic:

    Please select your field of practice:*

    Your message:* (required)

    Please enter

    Your email address*

    Title: MrMrsMsDrProf

    First Name*:

    Last Name*:







    Phone Number:

    Would you like to subscribe to one or more of our regular scientific publications?

    Air Water Soil (email)Chemical and Petrochemical Analysis (email)ElectroChem Matters (email)FoodLab and Beverage Analysis (email)Ion Chromatography News (email)Metrohm Australia Analyst (email)Metrohm Australia Analyst (print)Metrohm Information (print)Mines&Minerals (email)Process Analytics (email)Retsch the Sample (print)Solid Science (email)Teaching and Research (email)

    Please enter the displayed code: