AATCC 112:2020 pdf download.Test Method for Formaldehyde Release from Fabric: Sealed Jar
13.2 A simple cloth support for insertion in the mason jars can be constructed as follows:
A piece of aluminum wire screening 15.2 x 14.0 cm (6.0 x 5.5 in.) is bent around a length of wood 3.8 cm (1.5 in.) square and fastened together to form a rectangular, open-ended cage. One side is cut at the corners about halfway up the side and the cut section folded inward and fastened. This folded piece forms the bottom of the wire basket while the other three sides form the support legs. Fastening can be accomplished by twisting short lengths of wire through or around the appropriate part. The wire screening should not be a source of formaldehyde. Test before using.
13.3 The ratio of reagent to sample solutions can be adjusted, within limits, to suit the individual absorbance range and optical path length of the sampling tubes or cuvettes of the particular photometric instrument being used. For example. although 5 mL reagent to 5 mL sample solution has been Ibund convenient for several types of instruments, other I : I ratios. such as a ratio of 2 mL reagent to 2 mL sample may be more suitable for others. The same ratio should he used with the standards as with the sample. The use of spectrophotometer tubes directly for color developments avoids the transfer step. test tubes to spectrophotomeicr cells, and may save considerable time when many determinations are to be made. Repipeltes or similar devices can be used for reagent dispensing, and disposable tip automatic pipettes can be used for the sample solutions.
13.4 The procedure in Section 10 has been set up to cover the range from about 0 jig/g on the weight of the fabric to about 500 .ig!g. In fabrics containing releasable formaldehyde in the range from 500 ag/g on the weight of the fabric to about 3500 pglg, it is recommended that a ratio of lO-mL Nash reagent to I mL sample be used. If this is done. it is necessary to prepare an additional calibration chart with 10:1 ratios of standard solutions to Nash reagent by diluting 5.0, 10.0, 15.0 and 20.0 tg/ ml.. respectively, of the approximately 1 500 j.ig/mL standardized stock solution of formaldehyde to the mark with deionized water in 500-rnL volumetric flasks. Formaldehyde solutions containing approximately 15, 30, 45 and 60 tg/ mL respectively will be obtained (see 8.3).
13.5 The chromotropic acid colorimetric method can be used as an alternate to the Nash reagent for the determination of the formaldehyde content of the sample jars after oven incubation. It should be noted that the Precision and Bias Statement was not developed using the chromotropic acid method. A suitable procedure is given in J. Frederick Walker, Formaldehyde. 3rd Edition. Reinhold Publishing Co., NY, 1964, p470. When using this method, a change may be necessary in the size of both the aliquots taken from the sample jars (see 10.2) and the standard formaldehyde solutions used in preparing the calibration curve (see 8.3). CAUTION: Since concentrated sulfuric acid is used with the chromotropic acid method, adequate care should be exercised to protect operating personnel and spectrophotometric equipment.AATCC 112 pdf download.