Pink stain test

Perhaps ASTM E1428 (a. 16), commonly referred to as the Pink Stain test, is one of the most recognised plastic test methods. The actinomycete Streptoverticillium reticulum is used as an indicator organism to inoculate yeast malt extract agar. Test discs of plastic are placed on the surface and incubated at 29 °C for three weeks. Assessment focuses on the extent of staining of the 

This pigment is a prodigiosin-like pigment, actually a mixture of two prodiginines (a. 17) but is not exclusive to Streptoverticillium sp. 

Absence of staining indicates the effectiveness of the biostabiliser when compared to a control plastic. Streptoverticillium waksmanii produces a similar effect. 

ASTM E1428 pink stain (178) test of unprotected PVC samples 

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Pink staining test (usually a Petri dish procedure). 

Figure 8. ASTM El428, Pink Stain Test, Treated, Streptovericillium reticulum, zone of inhibition offungi around the test article...

Using a staining test with C.l. Basic Blue 3 (Astrazon Blue BG) PET fibres which have undergone titre reduction by alkali treatment can be identified, whereas by spraying with Astrazon Pink FG (0.5% in dichloromethane) they can be tested for barry dyeing. ... 

See also artificial weathering, autocatalytic degradation, biodegradation, corro-sion resistance, decomposition, deterioration, dew-cycle weathering test discoloration, pink staining, and xenon-arc aging. 

Borax or borates are tested for in the residue insoluble in alcohol. This is dissolved in water, rendered faintly acid with dilute hydrochloric acid, and a strip of turmeric paper immersed for a few minutes in the liquid. This is then dried in the water-oven, when if any boric acid compound is present, a bright reddish-pink stain is produced on the paper, which is turned blue on moistening with dilute alkali. 

The following photos demonstrate the Kirby-Bauer bacterial resistance test as well as the ASTM E-1428-96 pink staining organism test. 

Note The reagent can be employed on silica gel and cellulose layers. The coloration of the stained chromatogram zones is dependent on the temperature and duration of heating. For instance, cholesterol appears bluish-pink after heating to 75 — 80 °C for 3 —5 min [1], but yellow to brown-colored after heating for 20 — 30 min (cf. Procedure Tested ). 

Chondroitin sulfate (10 pi) and a negative control (50 pi of urine from a healthy subject) are spotted on each filter paper strip according to the procedure below. The test can be accepted when the negative control remains blue after staining, while the positive control turns into a pink-colored spot. 

This test is used to determine whether a membrane has been damaged by exposure to an oxidizer or by some sort of physical attack. In the Rhodamine B test, the membrane module is pressurized with a dye prior to autopsy. If the permeate turns pink, the membrane is probably damaged. Upon autopsy, damaged areas of the membrane will be stained pink. 

Identification Place a drop of a saturated solution of sample into a micro test tube, and add a drop of a 0.5% solution of ammonium chloride and several milligrams of zinc powder. Cover the mouth of the tube with a disk of filter paper moistened with a solution of 5% p-dimethylaminobenzaldehyde and 20% trichloroacetic acid in hexane. Heat with a small flame for about 1 min. A pink to red-violet stain appears on the paper. 

Perspiration tests similarly indicated the presence of two dyestuffs. In the alkali solution, the yellow color seemed to be removed almost completely, leaving a pink-colored fabric. In the acidic solution, the yellow dye migrated to the wool, silk, and nylon sections of the multifiber test strips, staining these fibers a bright yellow shade. The pink color seemed to bleed minimally a small amount of color was transferred in the alkali solution tests, but generally this pink color remained comparatively very fast. 

Various fibers may be identified, or separated from each other, through sequential dissolution in various solvents. As seen in Figure 6, silk is soluble in HCOOH/ZnCli, while wool does not dissolve. For bast fibers it is possible to discern some types with phloroglucin/HCl under a microscope. Jute will stain red, while hemp is only slight pink, and ramie and flax are unaltered. With the use of Kuoxam, ramie is dissolved while flax remains undissolved. For these tests, it is absolutely necessary to use reference materials ... 

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