Serial Dilution Bags explicitly included in ISO 7218:2024
Published in June 2024, the revised ISO 7218:2024 explicitly includes serial diluters and lists bags as suitable dilution containers in Section 6.4.4.1. Inlabtec is the world’s only manufacturer offering a bag-based serial dilution system.
Developed to minimize resource use and waste, the Inlabtec Serial Diluter automates diluent dispensing and mixing while reducing repetitive laboratory work, plastic consumption and storage requirements.
Practical verification procedures
ISO 7218:2024, Clause 6.4.4.4covers calibration and verification of dispensed volume and homogenization performance.
Inlabtec provides two complementary procedures for assessing homogenization and mixer function of the Serial Diluter UA and UC, with Inlabtec-defined acceptance criteria.Dispensed volumes are verified separately by gravimetric measurement.
Verification of homogenization performance
This microbiological procedure compares microbial counts before and after additional manual mixing of the same bag contents. No relevant change indicates sufficient automatic homogenization under the conditions tested.
Using the same dilution and bag keeps other influencing factors largely constant. The procedure supports initial verification and periodic assessment without maintaining a separate tube and vortex method solely for comparison.
Verification of the Homogenization Performance of the Inlabtec Serial Diluter
Mechanical mixer function check
A smartphone accelerometer and the free phyphox app are used to measure mixer speed and mixing time.
Correct speed and duration provide indirect evidence of consistent mixer function and, with an unchanged device configuration, support the assessment of consistent homogenization performance.
Mechanical Function Check of the Inlabtec Serial Diluter Mixer
Verification of dispensed volumes
Dispensed volumes must be checked separately by gravimetric measurement using an appropriate diluent. ISO 7218:2024 specifies limits of ±2% for dilution preparation. The procedure is described in the operating instructions under support/instructions.
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