Instruction Manual for Use of Urea Quick Test Kit in Bean Sprouts

Product Number: YPHM-10

1 Introduction

Urea, also known as carbonamide. The normal production cycle of bean sprouts is about 11 to 15 days, but some vendors spray urea, nitrate and rootless fertilizers and hormones on bean sprouts to shorten the ripening time in order to increase the yield of bean sprouts and shorten the production cycle. Bean sprouts sprouts sprouted with fertilizers and hormones such as urea, under the action of fertilizers and pesticides such as urea, will naturally become particularly long and white, and sometimes green leaves do not take root. They look tender and watery, which is indeed attractive and easy to sell at a high price; and when beans germinate, they can absorb more water, thereby increasing the yield of bean sprouts and making huge profits. Bean sprouts are different from other vegetables. The extensive use of urea and other chemical fertilizers in bean sprouts will lead to a significant increase in nitrate content in bean sprouts. When nitrate enters the human body, it will become carcinogenic nitrite after bacterial decomposition. Therefore, the urea residue of bean sprouts is harmful to the human body.

2 Detection principle

Urea in bean sprouts is extracted and reacted with a color reagent to produce a yellow substance. The color depth is proportional to the urea content within a certain range, and the urea content in the sample is read in contrast to the color card.

3 Detection range, suitable for rapid detection of urea content in bean sprouts.

4 Technical indicators

Lower limit of detection: 0.5mg/kg

5 You need to bring your own tools

Scissors, forceps, balances, purified water, water bath pot, pipette (1-5 ml), timer, goggles

6 Sample determination

Take 2 g of complete bean sprouts (try to be wound-free) in a 10 ml centrifuge tube, add purified water to a 10 ml scale, shake well and let stand for 5 minutes;

Take 5 ml of clear liquid and add it to another 10 ml centrifuge tube, add 10 drops of reagent A to it, add 1 ml of reagent B, 1 ml of reagent C, cover and mix well, put it in a boiling water bath, take out the test tube after 20 minutes and cool it under tap water for 2 minutes, compare it with the color card, find out the equivalent or similar to the color card Color scale, the value on the color scale is the content of urea in the sample.

7 Precautions

7.1 All reagents are not edible! Do not drip on the skin! Please keep the detection reagent properly!

7.2 Reagent A has the sour taste of vinegar, but it is non-toxic, please feel free to use it.

7 The test solution B used is a strong corrosive reagent. When it touches the skin, rinse it with a lot of water immediately.

7 Because the soybean sprouts matrix is more complex and has color, it is easy to cause false positives during testing. If there is a positive test, it needs to be judged by combining other indicators of bean sprouts.

7 This product is only used for initial screening. The final result is subject to the relevant national standard methods.

8 Storage conditions and valid period

Reagents are stored in a cool and dry place at 4-30 ° C, protected from light, and the valid period is 12 months.

9 Product composition

Serial number

Specifications

Composition

10 times/box

50 times/box

100 times/box

1

reagent A

1 bottle

1 bottle

1 bottle

1 bottle

2

reagent B

1 bottle

1 bottle

1 bottle

3

reagent C

1 bottle

1 bottle

1 bottle

1 bottle

4

screw 10 ml centrifuge tube (recyclable)

2

10

20

5

1 ml straw

10

50

100

6

color card

1

1

1

7

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