Test Method for Free and Hydrolyzed Formaldehyde

AATCC 206-2020 pdf download.Test Method for Free and Hydrolyzed Formaldehyde:Water Extraction.
A 1:10 dilution of the standardi7ed tinnaldehyde stock solution is prepared by pipetting 25-mL of the standardized stock solution into a 250-mt. volumetric flask and diluting to the mark with deionized water, The stock solution is then titrated and its concentration is determined as pgmL.
A 5-concentration calibration curve, which may include zero, is suggested, Prepare the calibration curve by pipetting from the following: 0. I. 3, 5. 10. 15. 20 and 30-mt. volumes of the 1:10 dilution into $00-mL volumetric flasks then adding deionized water to the 500-mi. level. (11 for example, the standardized stock solution were found to be 1470 pg/mI by titration, calculate new values for the calibration curve abscissa;
When 1.3,5. 10, 15,20 and 30- inL aliquots of the 1:10 dilution of the standardized stock solution from 8.1 are diluted with deionized water in 500-mt. volumetric flasks, formaldehyde solutions containing approximately 0.30. 0.90, 1.5, 3.0. 4.5, 6.0 and 9.0 pg/mt. formaldehyde respectively will be obtained. Record the calculated concentration of each solution as determined by section 9 Standardization of Stock Formaldehyde. The equivalent concentrations of the formaldehyde in the test fabric based on the weight of accurately known I gofihe test titbric and 100-mI. of water in the Erlcnmeyer flasks will be 100 times the accurate concentrations of these standard solutions.
Use 5 mL aliquots of each of the standard solutions and the procedure described in 11.4-11.7 to prepare a calibration chart in which igmL formaldehyde are plotted against absorhance.
Reagents: 1.0 M sodium sulfite (126 g Anhydrous Na2SOL), 0.02 N sulfunc acid (can be purchascd in standard. ized form from chemical supply companies or must be standardized from standard NaOH solution). Do not use commercial standardized sulfuric acid thai has been stabilized with formaldehyde. If there is a doubt, check with the chemical supplier.
Proccdurc:
A Pipette 50-mL of the 1.0 M sodium sullitc (Na.S03) into the beaker.
B. Pipette l0-mL of the stock formaldehyde solution to a beaker.
C. Titrate the solution with the standard 0.02 N H..S04 to an endpoint of pH of 9.5.
Record the volume of acid used to the nearest 0.01-mi.. (The volume of acid should be approimi(eIy 25-mL for 0.02 N acid.)
Repeat the titration standardization in duplicate or triplicate. Average the results.
Use the determined concentration in preparing the calibration curve for the colon metric analysis.
Samples should immediately be placed into separate zipper-type closure plastic bags when sampled. As an extra precaution for maintaining their original state the samples may be wrapped in aluininum foil before being placed in the plastic bags.
CUt approximately l-g specimens; weigh each one to * 0,01 g. Perform in duplicate for each sample. If ihcrc is a delay in testing the I -g specimens once they arc cut, they should be put back into the zipper-type closure plastic bags (and rcwrapped in foil if previously done) until testing commences.
Pipette l00.O-inL of deionized water into each Erlenmcyer tiask. Place a fabric specimen in each flask. The fabric should be completely submerged in the water and not float on the surface (see 14.6). A stirring rod may be used to push and keep the fabric below the water surface. Cap the flasks and place them in the water bath at 40± 1°C(105 ± 2°F) for 60 ± 2 mm. Shake the flasks every 5 mm by hand or use an ultrasonic water bath tiM agitation. If using an ultrasonic bath. check the water frequently for temperature changes.
Remoe the flasks from the water bath.
Remwe the fabric from the flasks, Recap the flasks and shake them to mix any condensation formed on the sides. Allow solutions to cool tbr 30 mm.
Pipette 5-niL of Nash reagent into a suitable number of tcst tubes. small (50- mL) Erlcnmcycr flasks, or other suitable flasks (colonmeter or spectrophoometer tubes can be used directly, six 14.4) and pipette 5-mL of the reagent into at least one additional tube for a reagent blank. Add 5-mL aliquots from each of the sample incubation jars to the tubes. Reagent blanks are prepared by adding 5-rnL of the Nash reagent and 5-mL of deionized water to the tubes.
Mix and place the tubes in a 40 ± lüC I05 ± 2üF) water bath for 30 ± I mm. Remove tubes frotn bath. Cap with stoppcr or plastic paraffin film and allow to cool to room temperature away from direct light.
Read the absorbance in the spec. trophotometer against the reagent blank at 412 tim, Caution: Exposure of the developed yellow color to direct sunlight for a period ot time will cause some fading. If there is appreciable delay in reading the tubes after color development and strong sunlight is present, care should be exercised to protect the tubes from light. Otherwise the color is stable for considerable time (at least overnight) and reading may be delayed (see 14.7 and 14.8).
Delennine the igmL. formaldehyde IHCHO) in the sample solutions using the prepared calibration curve (see 8.3 and 14.9).AATCC 206 free download.Test Method for Free and Hydrolyzed Formaldehyde