Malachite Green detected description

The "Introduction"

Malachite Green chemical functional groups of triphenyl methane can cause cancer in many countries has been disabled, but there is still used when fishermen in the treatment of fish infected with fungus, there are commercial-disinfection of transport, to prolong the survival of fish in long-distance traffic in time.

"Principle"

After extraction of Malachite Green in food, used for determination of the absorbance of the absorbance is proportional to the content within a certain range.

"Detected"

Beverages, pastries, candies, preserves, condiments, such as

"Technical specification"

Detection limit: 1mg/kg

Linear range: 1-25 mg/kg

"Steps"

1. sample preparation

① flavored water, sherbet, soda: weighing 100mL 20.0g sample beakers. Steam to heat getting rid of carbon dioxide.

II-wine: weighing 100mL 20.0g sample beaker, and fragments of porcelain pieces, heated drive ethanol.

③ hard candy, candied class, starch soft candy: weigh 5.0 or 10.0g grinding of samples, with 20mL water, warm dissolved liquid pH value is high, dropping 1-5 pretreatment reagent 1 adjust the PH value drops to about 4.

④ toffee: a weighing 20.0g crush homogeneous sample, plus 30mL pretreatment reagent 2 solution;

B water bath to concentrate on 20mL immediately with pretreatment reagent 1 to slightly acidic;

Pretreatment reagent 3 c plus 1.0mL;

D plus 1mL pretreatment reagent 4, protein precipitation, filters, wash with a little water, collecting filtrate.

⑤ cake: a weighing 20.0g crush homogeneous sample, add the sand of the sea, mixed and hot air drying (hand drying);

B mix with 30mL petroleum ether, place for a moment, poured out of petroleum ether, so repeat the process three times to remove fat;

C after drying grind fine, all poured into the hopper;

D pigment extracted by pretreatment reagent 2, until the stains all over;

E water bath to concentrate on 20mL immediately with pretreatment reagent 1 to slightly acidic;

F pretreatment reagent 3 plus 1.0mL;

4 g plus 1mL pretreatment reagents, protein precipitation, filtration and washing with a small amount of water, collecting filtrate.

2. adsorption and separation

① from the resulting heated to 70 degrees, add 0.5~ 1.0g detection reagent a mix;

II pretreatment reagent 1 adjust pH to 4, make the stain completely absorbed, such as solution there is color, you can add test reagent a;

③ adsorption of coloring agent detection reagent a into the funnel filter (absorbent). PH= 4 of 70 ℃ water repeatedly washed, 20mL, wash while stirring;

Black with natural colorants, 1~ 3 times then the test reagent b, 20mL, up to the washing liquid is colorless;

⑤ 70 ℃ washed several times to the outflow of the water solution is neutral. Washing process must mix;

⑥ pretreatment reagent 2 in foods-desorption all colouring agents (20ml), collected all the desorption liquid, ammonia in water bath to drive;

⑦ 2mL g desorption liquid 20mL colorimetric tubes, diluted with ethanol to 10mL scale.

3. sample test

① takes 2.5ml samples to be tested in the colorimetric;

② cell into the specified channel;

③ According to ' sample '.

"Criterion"

Not be detected.

"Considerations"

① with testing liquid have different degrees of damage to the skin, use protection. Carelessly filled with dry skin should immediately wash with plenty of water.

II save the test reagents need cool and dry place away from light, refrigerator 2~5℃ keeping the best.