BS ISO 4134:2021 pdf download – Meat and meat products — Determination of L-(+)- glutamic acid content — Reference method 7.5 Precision 7.5.1 Interlaboratory test The precision of the method was established by an interlaboratory test carried out in accordance with ISO 5725-1 and ISO 5725-2. The results of these tests have been published (see Reference [4]). The values derived from these tests may not be applicable to concentration ranges and matrices types other than those given. 7.5.2 Repeatability The value less than or equal to which the absolute difference between two test results obtained under repeatability conditions can be expected to be 0,55 % with a probability of 95 % of cases exceeding 0,159 2 g/100 g up to 0,305 0 g/100 g for L-(+)-glutamic acid contents. 7.5.3 Reproducibility The value less than or equal to which the absolute difference between two test results obtained under reproducibility conditions can be expected to be 0,82 % with a probability of 95 % of cases exceeding 0,159 2 g/100 g up to 0,305 0 g/100 g for L-(+)-glutamic acid contents. 7.6 Detection limit When W m (the moisture content of test sample in 7.3.4.4) is 70 and V 1 /50 (the dilution factor of filtrate taken in 7.3.3.6) is 1/15, the detection limit is 0,02 g/100 g of L-(+)-glutamic acid contents. 8 Test method of light absorption microplate reader 8.1 Reagents The reagents are the same as those used in 7.1. 8.2 Apparatus In addition to the equipment from 7.2.1 to 7.2.9, the following apparatus should be also included. 8.2.1 Single channel or multi-channel transferring pipettes and tips, of capacities 1 000 μl, 200 μl,100 μl and 20 μl conforming to ISO 8655-2. 8.2.2 Light absorption microplate reader, of wavelength 490 nm. 8.2.3 Microplate, of 96 holes (recommended), flat and transparent. 8.2.4 Brown glass vial, with caps, of volume not less than 1,5 ml. 8.3 Procedure 8.3.1 General If it is required to check whether the repeatability requirement is achieved, two separate determinations should be carried out. 8.3.2 Extraction of L-(+)-glutamic acid in the test portion The extraction method is the same as 7.3.2 and 7.3.3. 8.3.3 Determination 8.3.3.1 Preparation of detection instrument Set up the light absorption microplate reader (8.2.2), preheat the instrument according to the instrument specification until equilibrium conditions achieved. Set the detection parameters: the detection wavelength of 490 nm, the microplate reading mode by row and by...

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