Wednesday, January 5, 2011

HALPHEN-HICKS TEST

Boli a little cloth with a solution of (1 part phenol, 2 parts carbon tetrachltide)
settle, pour bromine  vapour on to the surface: colora- tion (varuing according to
the ptoduct) indicates resin oils.
PHENOLS (a) Heat a little cloth with 1 gm. phthalic anhydride containing 2-3
drops of conc. sulphuric acid until a rich brown melt is obtained. Cool, dilute
with water , make alkaline with NaOH : pink indicates phenols.
(B) boil a little cloth or resin with 5 c.c. water containing 1 drop conc. H2SO4
cool, add a few drops of carbazole (1-2% in 95% ethyl alcohol ) and 1-2 drops of
conc. H2SO : blue indicates phenol/formaldehyde resin. (C) place a litle cloth on
a spotting plate, add one or two drops conc. HCI< then 1 drop of phenol- cresol
bodies.
The test may be used on resin solution . (D)see test 21 (indophenols).

DETERGENTS AND WETTING AGENTS :


This group of bodies include true sopas, sulphonated castor-oil sops, sulphonated and sulphated fatty alcohols, synthetic detergents, quaternary compounds, and saponins, with which may be incorporated solvents, alkalis, disinfectants, builders, or oxidising agents. The  prooery which they have in common is the power to wet dirt oils and fats and textile fibers ;
detergent power is a property which may be regarded as wetting agents for oils and waxes, though their simplle action is probably merely one of blending with the fatty body , reducing its melting point and viscosity, and waxes, thereby making emulsification mechanically easier. If the wetting solvent is polar in character it may most also act as a bridge between the fat and deter-gent molecules.
The most common solvents are carbon tetrachloride, trichlorethylene, pyridine, cyclohexanol, pine oil, and in stringly alkaline liquors, cresylic acid .(continue)


NITRATE TEST

A little diphenylamine is dessolved in 1 c.c. 90% sulphuric acid.
A drop of resgent is placed on the fabiric: deep blue indicates nitrate,
e.g. cellulose nitrate.

SCHIFF'S TEST:

Schiff's reagent is made by dessolving 0.2 gm. rosaniline (fuschsine)
in 10 c.c. of cold water previously saturated by sulphur diocide. On
standing, the pink colour disappears. The reagent is kept in a dark- coloured,
stoppered bottle. The addition of aldehyde restores the pink colour.

SULPHAMIDE TEST:

Ammonium sulphamide is sometimes used in conjunction with synthetic
resins for fireprooofing. To 5c.c. of a water extract, add an equal
volume of 5% mercuri chloride: a precipitate may indicate sulphamide.
Confirmation: heat 5 c.c. of the original solution with IO% KOH solution
when vapours alkaline to litmus are given off.

CASEIN :

Boil the fabric in water ,cool, to 5c.c. add 1-2 drops of conc. H2 SO4and
I1 drop of 3% formaldehyde; pour gently on to c.c. of conc. H2 SO4 containing
1 drop of 10% ferric chloride, without mix- ing: violet indicates casein, provided it
is present in a from sufficiently soluble for extraction.

(A) A little cloth is boiled with conc. HCI to hydrolyse any protein present into 
amino-acids. A small portion of solution is made alkaline with dilute NaOH and a 
drop of delute copper sulphable proteins (e.G.,glue) give the reaction by extraction 
with water onle. (B) spot the fabric with copper sulphate solution, stand several minutes, 
then dip in dilute NaOH solution : deep vidicates protein.