3.2. Stability of the enzyme sensor
The response of the immobilised DAO remained stable during
the first 30 injections throughout the day but was not reusable
the day after due to a dramatic decrease in the sensitivity. Furthermore,
the repeatability (coefficient of variation, CV) in standard
and fermented sausage extract (42 days of curing) demonstrated
very good results (3.51% and 5.39%, respectively). The stability of
the immobilised DAO membrane during storage under refrigeration
was confirmed by using one membrane per week (Fig. 2). After
6 weeks, the response began to decrease. This assay also confirmed
the reproducibility of the immobilisation procedure (CV = 1.7%).