AATCC 98-2016 Alkali in Bleach Baths Containing Hydrogen Peroxide
2. Principle
2.1 A weighed specimen of the bleach bath is titrated with a standardized solu- tion of sulfuric acid to a Phenol Red end- point, or to the pH range 6.8-8.4 on a pH meter. The total alkali, expressed as % NaOH, is calculated based on the weight of the bath.
3. Terminology
3.1 bleaching, n.—elimination of un- wanted coloring matter from a substrate by oxidative or reductive chemical treatment.
4. Safety Precautions NOTE: These safety precautions are for information purposes only. The safety precautions are ancillary to the testing procedures and are not intended to be all inclusive. It is the user’s responsibility to use safe and proper techniques in handling materials in this test method. Manu- facturers MUST be consulted for specific details such as material safety data sheets and other manufacturer’s recommendations. All OSHA standards and rules must also be consulted and followed.
4.1 Good laboratory practices should be followed. Wear safety glasses in all laboratory areas.
4.2 All chemicals should be handled with care. Sulfuric acid is corrosive. When preparing the dilute solutions from pure or concentrated reagents, use chemi- cal goggles or face shield, impervious gloves, and an impervious apron. CAU- TION: Always add acid to water.
4.3 An eyewash/safety shower should be located nearby and a high efficiency particulate respirator with organic vapor cartridge and full facepiece should be readily available for emergency use. 4.4 Exposure to chemicals used in this procedure must be controlled at or below levels set by governmental authorities (e.g., Occupational Safety and Health Administration’s [OSHA] permissible ex- posure limits [PEL] as found in 29 CFR 1910.1000; see web site: www.osha.gov for latest version). In addition, the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Values (TLVs) comprised of time weighted averages (TLV-TWA), short term exposure limits (TLV-STEL) and ceiling limits (TLV-C) are recommended as a general guide for air contaminant ex- posure which should be met (see 10.1).
5. Apparatus and Materials
5.1 Potassium acid phthalate (C 8 H 5 O 4 K), ACS Reagent.
5.2 Phenol Red (phenol-sulfonphthalein), or 0.06% solution thereof, if a pH meter is not used as an alternative.
5.3 Methanol (CH 3 OH) (not needed if 0.06% Phenol Red solution is available).
5.4 Sulfuric acid (0.1N) (H 2 SO 4 ), ACS Reagent, 95-98%, or 0.1N (see 6.1 and 10.2).AATCC 98 pdf download.