Feasibility of using quantitative 1H-NMR spectroscopy and ultra-microbalances for investigation of a PET microplastic reference material

We report on the feasibility of using quantitative NMR and ultra-micro balances for additional measurements of the mass of Poly-Ethylene Terephthalate particles (PET) in a Reference Material (RM). The microplastic (MP) PET particles were immobilised in solid NaCl following freeze-drying of a 1 ml NaCl-suspension. More than 500 such samples of PET particles in the NaCl-carrier were prepared and later used in an inter laboratory comparison. In addition to the original results obtained by weighing, two independent results of quantitative 1H-NMR have now been obtained for further investigation of this reference material together with one additional set of weighing data. The NMR data were used for confirmation of the weighed amount of. Average masses of 0.29 ± 0.04 mg and 0.37 ± 0.02 mg of PET were obtained using two different ultra-micro balances (14, % RSD for n = 14 and 4.8 % RSD for n =7). The 1H-NMR data was 0.30 ± 0.02 mg of PET (6.7 % RSD for n = 5) and 0.34 ± 0.04 mg of PET (12.5 % RSD for n = 14), respectively. The average mass of PET obtained by 1H-NMR measurements was in agreement with the weighed amounts within their standard deviations. A provisional property value of 0.328 mg PET with an expanded uncertainty of 0.068 mg (±20.7 % relative) was obtained by applying approaches described in ISO 17034 and ISO Guide 35. Measurement of PET by quantitative 1H-NMR spectroscopy is also reported for a water sample.

SEGHERS John;  GUNTHER Marcel;  BREIDBACH Andreas;  PEEZ Nadine;  IMHOF Wolfgang;  EMTEBORG Hakan; 

2023-07-14

SPRINGER HEIDELBERG

JRC131218

1618-2642 (online),   

https://doi.org/10.1007/s00216-023-04567-0,    https://publications.jrc.ec.europa.eu/repository/handle/JRC131218,   

10.1007/s00216-023-04567-0 (online),