The invention relates to a piece of
highly sensitive pH test paper and a preparation method thereof, wherein a developing strip is in the form of a piece of pH body paper, which is dipped in a
reagent solution and then dried by hot air at constant temperature; the
reagent solution contains an indicator; the formula of the indicator contains
bromothymol blue,
thymol blue, metanil yellow, m-
methyl red,
bromocresol green, nitrazine yellow,
cresol red,
phenolphthalein, para-nitrophenylazosalicylate
sodium, titan yellow, fluorescent
pigment orange red, 5% 4-nitrobenzenediazo-1-naphthol-3.6-
sodium disulfonate solution and 30% dissolved
ethanol aqueous solution; and the formula of the indicator further contains an aqueous colour fixing agent, a cotton wooden fibre
mildew preventive, a special paper
mildew preventive and a buffer neutralizer formed by modulating
sodium hydroxide and
phosphoric acid. The preparation method comprises the following steps of: adjusting the
reagent solution till a pH value is up to 6-7.5, uniformly
wetting the pH body paper, and
drying through hot air at constant temperature. According to the invention, the reagent solution can be adjusted, so that the pH value is up to 6-7.5; steady and precise high sensitivity of the pH1-14 test paper is effectively increased; and the test paper is convenient and simple to use.