Formaldehyde detection kit

Abstract

The utility model provides a formaldehyde detection kit which comprises a color developing agent dripping device, and the color developing agent dripping device comprises a receiving pool, a dripping pool, a dripping pool cover and a connecting support rod; the receiving tank is used for receiving liquid dripped from the dripping tank; a base of the dripping pool is provided with an operation part for dripping liquid; the drip tank cover is positioned at the upper part of the drip tank and comprises an inner layer cover and an outer layer cover, and the inner layer cover and the outer layer cover are matched to adjust the speed of liquid in the drip tank flowing to the receiving tank. According to the color developing agent dripping device disclosed by the utility model, through the double-layer dripping design, the contact area of absorption liquid and formaldehyde is increased, the absorption effect on the formaldehyde is obviously improved, and the formaldehyde detection application in multiple scenes is realized.

Description

TECHNICAL FIELD

[0001] The utility model relates to a formaldehyde semi-quantitative rapid detection kit, which can be used for determining the formaldehyde concentration in different scenes such as air, water, vegetables, fruits, food soaking liquid and the like. BACKGROUND

[0002] Formaldehyde is a common chemical pollutant and widely exists in air and some food processing processes. Formaldehyde in the air mainly comes from board in indoor decoration materials, and formaldehyde in food often comes from illegally added preservatives and bleaching agents. Formaldehyde has genetic toxicity and reproductive toxicity, which not only causes irritation of skin and mucous membrane, but also can cause damage to the immune system and even induce nasopharyngeal carcinoma and leukemia. Long-term exposure to high-concentration formaldehyde not only seriously endangers the health of residents, but also brings huge losses to the medical economy.

[0003] In recent years, food safety problems have occurred frequently, and the public's health protection consciousness has gradually increased, so there is an urgent need for a household formaldehyde rapid detection product that is suitable for families, low in price and easy to operate, which can detect formaldehyde in air and food at any time and any place and preliminarily judge the potential risk factors affecting human health.

[0004] At present, the detection methods of formaldehyde mainly include instrument method and chemical method. The instrument method is accurate, but the equipment is expensive and the operation is complex; the chemical method is based on color reaction and detected by a spectrophotometer, which requires professional equipment and technology, and both of them are not suitable for popularization and use among ordinary people. Some formaldehyde rapid detection products based on chemical method on the market, such as the utility model patents with authorization announcement numbers CN 209802998 U and CN 2551996 Y, are limited to air monitoring in a single field, and there is still a lack of a formaldehyde rapid detection product that can be applied in multiple scenes such as indoor air, water source and food safety. UTILITY MODEL CONTENT

[0005] In view of the deficiencies of the prior art and actual needs, the utility model develops a formaldehyde rapid detection kit with simple operation, rapid color development and strong stability, which can be used in multiple scenes and realizes rapid determination of formaldehyde in air, water and food soaking liquid.

[0006] The utility model provides a formaldehyde detection kit, which comprises a color developing agent dripping device, wherein the color developing agent dripping device comprises a receiving pool, a dripping pool, a dripping pool cover and a connecting strut;

[0007] The receiving pool comprises a base and a side wall extending upward along the circumference of the base, and the base and the side wall form a reaction cavity for receiving liquid dripping from the dripping pool;

[0008] The drip cell comprises a base with an operation part and a cup wall arranged along the circumference of the base and extending upward, and the base and the cup wall form a containing cavity;

[0009] The drip cell cover is used when measuring the formaldehyde content in the air, comprising an inner cover and an outer cover, the inner cover is provided with a first adjusting part penetrating the inner cover body, the outer cover is provided with a second adjusting part penetrating the outer cover body, and the first adjusting part can adjust the speed of the liquid in the containing cavity of the drip cell flowing to the reaction cavity of the receiving cell under the cooperation of the second adjusting part;

[0010] The lower surface of the inner cover comprises an adapter part with a preset depth, and is also provided with an operation rod extending downward, the length of the operation rod exceeds the preset depth of the adapter part, and the operation rod is used to penetrate the operation part of the drip cell during the process of the inner cover being downwardly covered on the drip cell;

[0011] The two ends of the connecting strut are respectively connected to the upper edge of the side wall of the receiving cell and the base of the drip cell, so that the drip cell is supported above the receiving cell.

[0012] In one or more embodiments, the upper surface of the inner cover is provided with a cooperating part which does not penetrate the inner cover body;

[0013] The outer cover is also provided with a limiting block and a positioning block penetrating the outer cover body; the limiting block is arranged at the side end of the second adjusting part, and when the outer cover is downwardly covered on the inner cover, the limiting block penetrates the first adjusting part; the positioning block is used to be positioned in the cooperating part of the inner cover when the outer cover is downwardly covered on the inner cover.

[0014] In one or more embodiments, the first adjusting part and the second adjusting part are circular ring-shaped slits, respectively located at 3 / 4~1 / 4 radius away from the center point of the inner cover and the outer cover;

[0015] The positioning block is a center buckle, and the inner cover and the outer cover are relatively rotated through the center buckle to adjust the exposed length of the slits to control the speed of liquid dripping.

[0016] In one or more embodiments, the operation part of the drip cell is arranged at the center point of the bottom surface of the base for jack operation, and the operation part is a cross-shaped soft connection or a circular film.

[0017] In one or more embodiments, the circumferences of the receiving cell and the drip cell are circular;

[0018] The base is integrally formed with the side wall, one or more clamping slots and a flow guide are formed on the side wall relative to one end of the base, the clamping slots are arranged at intervals at the top end of the side wall, and the flow guide is arranged outwardly protruding from the surface of the side wall to facilitate the flow of liquid in the reaction cavity; when there are two or more clamping slots, the flow guide is arranged between the two clamping slots.

[0019] The base of the drip tank is provided with a connecting slot corresponding to the clamping slot of the receiving tank, the connecting slot does not penetrate the base, and the connecting slot of the drip tank is selectively connected with the clamping slot of the receiving tank through a connecting strut, so that the drip tank is supported above the receiving tank.

[0020] In one or more embodiments, the upper part of the cup wall of the drip tank is provided with a fastening part, which is the outer surface of the cup wall, and a step is arranged between the fastening part and the outer surface of the cup wall;

[0021] The adapter of the inner cover can be connected with the fastening part of the drip tank by interference fit or threaded connection.

[0022] Preferably, the width of the circular annular gap is 1-3 mm, for example, it can be 1 mm, 2 mm or 3 mm.

[0023] Preferably, the size of the cross-shaped flexible joint is (2-8) mm x (2-8) mm, for example, it can be 2 mm x 2 mm, 3 mm x 3 mm, 4 mm x 4 mm, 5 mm x 5 mm, 6 mm x 6 mm, 7 mm x 7 mm or 8 mm x 8 mm.

[0024] The diameter of the circular film is (2-8) mm, for example, it can be 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm or 8 mm.

[0025] Preferably, the base of the receiving tank is circular with a diameter of 2-5 cm, for example, it can be 2 cm, 2.5 cm, 3 cm, 3.5 cm, 4 cm, 4.5 cm or 5 cm, and the height of the side wall of the receiving tank is 1-3 cm, for example, it can be 1 cm, 1.5 cm, 2 cm, 2.5 cm or 3 cm.

[0026] Preferably, the base of the drip chamber is circular with a diameter of 2-5 cm, for example 2 cm, 2.5 cm, 3 cm, 3.5 cm, 4 cm, 4.5 cm or 5 cm, and the cup wall of the drip chamber has a height of 1-5 cm, for example 1 cm, 1.5 cm, 2 cm, 2.5 cm, 3 cm, 3.5 cm, 4 cm, 4.5 cm or 5 cm.

[0027] Preferably, the length of the operating rod is 1-3 cm, for example 1 cm, 1.5 cm, 2 cm, 2.5 cm or 3 cm, and the cross section of the operating rod is circular with a diameter of 1-5 mm, for example 1 mm, 2 mm, 3 mm, 4 mm or 5 mm.

[0028] Preferably, the connecting strut stably supports the drip chamber above the receiving chamber by buckling, and the number of the connecting struts is 2-4, for example 2, 3 or 4, and the length of the connecting struts is 4-8 cm, for example 4 cm, 5 cm, 6 cm, 7 cm or 8 cm.

[0029] As a preferred technical solution, the formaldehyde detection kit comprises a chromogenic agent drip device, the chromogenic agent drip device is a white plastic product, and comprises a receiving chamber, a drip chamber, a drip chamber cover and a connecting strut;

[0030] The diameter of the bottom surface of the circular receiving chamber is 4 cm, and the height of the chamber is 1.7 cm.

[0031] The diameter of the bottom surface of the circular drip chamber is 3.5 cm, the height of the chamber is 2 cm, the inner wall has a scale, and the indicated volume is 5 mL; the center point of the bottom of the circular drip chamber is a 5 mm*5 mm cross-shaped soft connection or a 5 mm diameter circular film, facilitating operation from the center jack;

[0032] The drip chamber cover is a double-layer design, the inner layer cover is provided with a 1 / 4 circular annular gap with a width of 2 mm at a radius of 2 cm from the center point, and the 0-4 numbers are labeled at equal distances, the outer layer cover is a 3 / 4 circular surrounding design, and the inner layer cover and the outer layer cover can rotate relative to each other through the center buckle; the inner layer cover is connected to a sharp plastic rod with a length of 2.5 cm and a diameter of 2.5 mm at the center point of the side facing the drip chamber, the sharp plastic rod can penetrate the soft connection at the center point of the bottom surface of the drip chamber in the process of rotating the drip chamber cover, so that the liquid flows downward, plays a role of flow guiding, and the exposed length of the gap is adjusted by rotating the inner and outer layers of the drip chamber cover, so as to control the dropping speed of the liquid.

[0033] The connecting support rods are three thin tubes with a height of 5 cm, which are used to connect the receiving pool and the circular dripping pool to form a support, and the dripping pool is stably supported above the receiving pool through buckles.

[0034] The formaldehyde detection kit also comprises a powder-type absorbent, a liquid diluent, a liquid color developing agent, a colorimetric card and a colorimetric dish.

[0035] The main components of the powder-type absorbent are phenol reagent (C6H4SN (CH3) CNNH2•HCl, abbreviated as MBTH) and lactose (diluent), and the mass ratio of the two is 1:10, which are stored in a light-proof tin foil bag, and the preparation method is to grind the phenol reagent and the lactose through a 60-80 mesh sieve respectively, mix them uniformly and then sieve again to ensure that the two are thoroughly mixed.

[0036] The main component of the liquid diluent is pure water, which is stored in a white or transparent plastic bottle, and is prepared into a formaldehyde absorption liquid with the powder-type absorbent when determining the formaldehyde content in the air.

[0037] The main component of the liquid color developing agent is an ammonium ferric sulfate hydrochloric acid solution, which is stored in a light-proof brown plastic bottle, and its role is to provide an acidic color developing system for formaldehyde.

[0038] The colorimetric card has at least two sets, and 18 color scales are set according to the formaldehyde concentration in the detected sample, so as to perform color developing comparison.

[0039] The colorimetric dish is a 1cm*1cm*3cm chamber made of transparent material.

[0040] Compared with the prior art, the utility model has the following beneficial effects:

[0041] (1) The color developing agent dripping device of the utility model does not change the size of the receiving pool, and through the double-layer dripping design, on the one hand, the liquid slowly falls down through the pressure adjustment of the operating rod and the double-layer cover, and on the other hand, after the dripping process reaches equilibrium, the device changes from single-layer adsorption to double-layer adsorption, thereby increasing the contact area of the absorption liquid and the formaldehyde and significantly improving the absorption effect of the formaldehyde: according to 1 drop of liquid being 0.02-0.1 mL, 3 mL has 30-150 drops of liquid falling into the receiving pool, and in this process, dozens to hundreds of liquid drops form a short-term dynamic adsorption with the formaldehyde, and this kind of adsorption is not possessed by the same kind of products at present.

[0042] (2) Compared with other similar formaldehyde rapid measurement products, the color developing agent dripping device of the utility model increases the determination sensitivity in the same time, and saves the absorption reaction time under the same color developing effect.

[0043] (3) The formaldehyde detection kit realizes multi-scene application, can be used for determination of formaldehyde concentration in air, and can be used for health and safety screening of water, various vegetables, fruits, dry goods and seafood, and can be used in combination or alone according to needs. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 is a side view of the color developing agent dripping device;

[0045] Figure 2 is a side view of the receiving pool;

[0046] Figure 3 is a bottom side view of the color developing agent dripping device;

[0047] Figure 4 is a top side view of the color developing agent dripping device;

[0048] Figure 5 is a structure diagram of the dripping pool cover of the color developing agent dripping device;

[0049] Figure 6 is a connecting structure of the dripping pool and the dripping pool cover;

[0050] Figure 7 is an air formaldehyde colorimetric card;

[0051] Figure 8 is a water and food soaking liquid formaldehyde colorimetric card;

[0052] Figure 9 is a color developing effect visual colorimetric result of the formaldehyde detection kit of the utility model and eight market formaldehyde rapid detection products;

[0053] Figure 10 is a rapid detection method color developing stability result;

[0054] Among them, 1-color developing agent dripping device, 11-receiving pool, 12-dripping pool, 13-dripping pool cover, 14-connecting strut, 111-base, 112-side wall, 113-slot, 114-flow guide part, 121-base, 122-cup wall, 123-operation part, 124-fastening part, 131-inner cover, 132-outer cover, 1311-first adjusting part, 1312-matching part, 1313-adapting part, 1321-second adjusting part, 1322-limiting block, 1323-positioning block. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical scheme and technical effect of the utility model more clearly understood, the utility model will be further described below, but the protection scope of the utility model will not be limited in the following examples only.

[0056] Example 1

[0057] The formaldehyde detection kit comprises an outer package and a series of contents in the package. The contents include a color developing agent dripping device 1, an absorbent, a diluent, a color developing agent, a colorimetric card, and a colorimetric dish.

[0058] The details are as follows:

[0059] As shown in Figure 1 , the color developing agent dripping device 1 comprises a receiving pool 11, a dripping pool 12, a dripping pool cover 13, and a connecting branch 14. In one or more embodiments, the receiving pool 11 and the dripping pool 12 can be circular or other shapes in the circumferential direction; the color developing agent dripping device 1 can be made of white plastic.

[0060] As shown in Figure 2 , the receiving pool 11 comprises a base 111 and a sidewall 112 extending upward along the circumferential direction of the base 111, and the base 111 and the sidewall 112 form a reaction cavity for receiving the liquid dripping from the dripping pool 12. In one or more embodiments, the base 111 and the sidewall 112 are integrally formed, and one or more clamping grooves 113 and a flow guide part 114 are formed on the sidewall 112 relative to one end of the base 111. In one or more embodiments, the clamping grooves 113 are arranged at intervals at the top end of the sidewall 112, and the flow guide part 114 is arranged outwardly protruding from the surface of the sidewall 112 to facilitate the flow of liquid in the reaction cavity; when there are two or more clamping grooves 113, the flow guide part 114 is arranged between the two clamping grooves 113.

[0061] As shown in Figure 3 , the dripping pool 12 comprises a base 121 having an operating part 123 and a cup wall 122 extending upward along the circumferential direction of the base 121, and the base 121 and the cup wall 122 form a containing cavity. In one or more embodiments, the base 121 of the dripping pool 12 is provided with a connecting groove corresponding to the clamping groove 113 of the receiving pool 11, and the connecting groove does not penetrate the base 121. The connecting groove of the dripping pool 12 is selectively connected with the clamping groove 113 of the receiving pool 11 through the connecting branch 14, so that the dripping pool 12 is supported above the receiving pool 11. In one or more embodiments, the upper part of the cup wall 122 of the dripping pool 12 is provided with a fastening part 124, which can be the outer surface of the cup wall 122, and a step is arranged between the fastening part 124 and the outer surface of the cup wall 122. In one or more embodiments, the operating part 123 of the dripping pool 12 is arranged at the center point of the bottom surface of the base 121, and is used for plug-in operation. The operating part 123 of the dripping pool 12 is a cross-shaped soft connection or a circular film.

[0062] As shown in Figure 4 , Figure 5 , and Figure 6As shown, the drip pool cover 13 comprises an inner cover 131 and an outer cover 132. The upper surface of the inner cover 131 is provided with a fitting portion 1312 which does not penetrate the inner cover body and a first adjusting portion 1311 which penetrates the inner cover body. The lower surface of the inner cover 131 comprises an adapting portion 1313 having a preset depth. In one or more embodiments, the adapting portion 1313 of the inner cover 131 can be connected with the fastening portion 124 of the drip pool 12 by interference fit or threaded connection. In one or more embodiments, the first adjusting portion 1311 of the inner cover 131 can adjust the speed of liquid flowing from the accommodating cavity of the drip pool 12 to the reaction cavity of the receiving pool 11 under the cooperation of the outer cover 132. In one or more embodiments, the lower surface of the inner cover 131 is further provided with an operating rod 133 extending downward. The length of the operating rod 133 exceeds the preset depth of the adapting portion 1313. The operating rod 133 is used to pass through the operating portion 123 of the drip pool 12 during the process of fastening the inner cover 131 downward on the fastening portion 124 of the drip pool 12.

[0063] The outer cover 132 is provided with a second adjusting portion 1321 which penetrates the outer cover body, a limiting block 1322 and a positioning block 1323. The limiting block 1322 is arranged at the side end of the second adjusting portion 1321 and penetrates the first adjusting portion 1311 of the inner cover 131 when the outer cover 132 is covered on the inner cover 131. The positioning block 1323 is positioned in the fitting portion 1312 of the inner cover 131. In one or more embodiments, the first adjusting portion 1311 and the second adjusting portion 1321 are circular ring-shaped slits located at 1 / 2 radius from the center point of the inner cover 131 and the outer cover 132. The positioning block 1323 is a center buckle. The inner cover 131 and the outer cover 132 are relatively rotated through the center buckle to adjust the exposed length of the slits to control the speed of liquid dripping.

[0064] In the embodiment, the diameter of the bottom surface of the circular receiving pool 11 is 4 cm, and the pool height is 1.7 cm. The diameter of the bottom surface of the circular drip pool 12 is 3.5 cm, and the pool height is 2 cm. The inner wall has a scale indicating a volume of 5 mL. The center point of the bottom of the circular drip pool 12 is a 5 mm x 5 mm cross-shaped soft connection or a circular film with a diameter of 5 mm. The inner cover 131 and the outer cover 132 of the drip pool cover 13 are provided with a 1 / 4 circular ring-shaped slit with a width of 2 mm at a radius of 2 cm from the center point. The slit is labeled with numbers 0-4 at equal distances. The length of the operating rod 133 connected to the center point of the inner cover 131 is 2.5 cm, and the cross-sectional diameter is 2.5 mm. The connecting branch rod 14 is three thin tubes with a height of 5 cm.

[0065] The absorbent is a powder-type absorbent, and the main components are phenol reagent (C6H4SN (CH3) CNNH2•HCl, abbreviated as MBTH) and lactose (diluent), and the mass ratio of the two is 1:10, which is stored in a light-proof tin foil bag. The preparation method is to grind the phenol reagent and lactose through a 60-80 mesh sieve respectively, then mix them evenly and sieve again to ensure that they are thoroughly mixed.

[0066] The diluent is a liquid diluent, and the main component is pure water, which is stored in a white or transparent plastic bottle. When used, it is prepared into formaldehyde absorption liquid with the powder-type absorbent.

[0067] The color developing agent is a liquid color developing agent, and the main component is an ammonium ferric sulfate hydrochloride solution, which is stored in a light-proof brown plastic bottle. Its role is to provide an acidic color developing system for formaldehyde.

[0068] There are two sets of colorimetric cards, which are used for colorimetric determination of formaldehyde content in air and food soaking liquid respectively. According to the formaldehyde concentration of the detected sample, 18 color scales are set (such as Figure 7 and Figure 8 ) to facilitate color comparison.

[0069] The colorimetric cell is a small chamber with a size of 1 cm x 1 cm x 3 cm, made of transparent plastic.

[0070] Example 2

[0071] (1) The formaldehyde detection kit of Example 1 is used to determine the formaldehyde content in the air, including the following steps:

[0072] Preparation before determination: Close the doors and windows, air purification equipment and fresh air system of the room to be determined according to “Indoor Air Quality Standard” (GB / T18883-2022) for at least 12 hours. When sampling, keep the doors and windows, air purification equipment and fresh air system closed, and keep the air conditioner running normally in the room with air conditioner;

[0073] Sample collection: Assemble the color developing agent dripping device according to Figure 1 Place it on the table surface 1.0-1.5 m away from the ground; pour the powder-type absorbent into the liquid diluent, shake it well, then slowly pour it into the circular dripping pool, cover the dripping pool cover; the sharp plastic rod in the cover penetrates the bottom of the circular dripping pool, rotate the dripping pool cover to expose the gap to the scale “1”, and the liquid drops slowly, if the dripping speed is too fast, the gap can be reduced; after the liquid covers the bottom of the circular receiving pool (about 3.0 mL), remove the dripping pool cover, at this time the liquid continues to drop under the action of gravity, when the liquid gravity and surface tension in the dripping pool reach balance, the liquid stops falling, at this time there is some liquid in the circular receiving pool and the circular dripping pool; stand for 15 minutes to allow formaldehyde in the air to fully react with the absorbent in the dripping pool, then transfer all the liquid in the dripping pool to the receiving pool;

[0074] Color development: pour the color developing agent into the receiving pool, shake gently, and after 5 min, move into the cuvette and compare with the air color card to get the formaldehyde concentration in the air.

[0075] (2) Using the formaldehyde detection kit of Example 1 to determine the formaldehyde content in water or food soaking liquid, including the following steps:

[0076] Sample collection: shake the food soaking liquid, pour into a round receiving pool, at this time the volume of the soaking liquid is 5 mL;

[0077] Reaction: pour the powder type absorbent into the receiving pool containing the soaking liquid, shake gently, and make the powder type absorbent completely dissolved; during this process, the formaldehyde in the soaking liquid reacts with the absorbent;

[0078] Color development: pour the color developing agent into the receiving pool, shake gently, and after 10 min, compare with the liquid color card to get the formaldehyde concentration in the soaking liquid.

[0079] Example 3

[0080] Take 6 10 mL stoppered colorimetric tubes, add formaldehyde standard solution according to Table 1, dilute to 5 mL with distilled water, and get formaldehyde standard series.

[0081] Table 1 Formaldehyde standard series

[0082]

[0083] Take two sets of the above standard series, one set uses the formaldehyde detection kit of Example 1 to determine the formaldehyde content, and the other set uses the national standard method (GB / T 18204.2) to determine the formaldehyde content, and then both use 1 cm cuvette to determine the absorbance of each tube at a wavelength of 630 nm, with water as the reference. With the formaldehyde content as the ordinate and the absorbance as the abscissa, draw the curve, calculate the regression equation, see Table 2.

[0084] Table 2 Linear range and regression equation of Example 1 and national standard phenol reagent method

[0085]

[0086] The results show that the formaldehyde detection kit of Example 1 has no difference with the national standard method in the determination range and linearity, and meets the methodological requirements.

[0087] Example 4

[0088] Under the same actual scene, the formaldehyde detection kit of Example 1 and the market mainstream brand formaldehyde rapid test product were used respectively to carry out formaldehyde concentration determination experiment, the reaction time of the formaldehyde detection kit of Example 1 was 15 min and 30 min, the reaction time of the market mainstream brand according to the instruction was 30 min, the absorbance A value measured by spectrophotometry was as shown in Table 3, and the visual colorimetric result was as shown in Figure 9 .

[0089] Table 3 Color development effect (absorbance A) of Example 1 and market product

[0090]

[0091] The absorption effect of formaldehyde in the air is affected by the liquid area and time of contact between the absorbent and formaldehyde, according to the adsorption rate formula r=kxCXS, wherein k represents the adsorption reaction rate constant, C represents the concentration of the substance in the gas, and S represents the effective adsorption site number, which represents the contact area of formaldehyde and the absorption liquid in the utility model.

[0092] The market product adopts single color development cell design, and the reaction time is different from 30 min to 2 h; the formaldehyde detection kit of Example 1 adopts double-layer dripping design color developing agent dripping device without changing the size of the receiving cell, the contact area S is increased by several times through the multi-layer and multi-hole structure, taking a circular color developing agent dripping device with a diameter of 4 cm as an example, the total volume of the absorption liquid is 5 mL, the single-layer adsorption area is 12.56 cm 2 , and the double-layer adsorption area is 22.18 cm 2 after adding an absorption cell with a diameter of 3.5 cm, the adsorption area is increased by 77%, and the adsorption amount of formaldehyde is significantly improved. At the same time, the dripping structure makes the absorption liquid drop in the initial stage, not only increases the contact time with formaldehyde in the air, but also increases the surface area of the absorption liquid contacting with formaldehyde by dividing the whole into parts, and significantly improves the capture efficiency of the absorption liquid to formaldehyde.

[0093] Compared with the average color development effect of the market formaldehyde rapid test product, the formaldehyde detection kit of Example 1 adopts double-layer dripping design color developing agent dripping device, and the color development effect is significantly improved under the reaction time of 15 min and 30 min, and the improvement rate is as shown in Table 4.

[0094] Table 4 Improvement rate of different color developing agent devices relative to the average color development effect of the mainstream brand

[0095]

[0096] The results show that the double-layer color development effect is better than the single-layer in the two time windows of 15 min and 30 min; the color development effect of the double-layer is improved after adding the dripping process; the color development effect of the double-layer+dripping in 15 min is the best, which is 121% higher than the average value of mainstream brands, and the color development in 15 min is better than that in 30 min.

[0097] In addition, the formaldehyde detection kit of Example 1 selects lactose as the diluent and auxiliary agent for formaldehyde color development. The absorbance value determined by spectrophotometry is 0.271, which is significantly better than anhydrous sodium sulfate (0.081) and sodium chloride (0.087) as a diluent, and also significantly higher than the commercially available products in Table 3. The formaldehyde detection kit of Example 1 improves the formaldehyde reagent formula, adds lactose as a diluent and color development auxiliary agent in the absorbent, so that the formaldehyde color development speed is faster and the sensitivity is higher.

[0098] To ensure the accuracy of the results, the formaldehyde detection kit of Example 1 compares the color cards according to different application scenarios:

[0099] Air formaldehyde colorimetric card calibration: In a 1 m 3 closed experimental cabin, different concentrations of formaldehyde were generated, the formaldehyde concentration in the cabin was monitored in real time using a formaldehyde direct-reading instrument, the formaldehyde concentration was ensured to be stable at the set value, the reagents in the formaldehyde detection kit were added according to the operation of Example 2, and the color displayed by the receiving pool in the kit was the color development chroma at the set concentration, according to which the air formaldehyde colorimetric card was developed.

[0100] Water and food soaking solution formaldehyde colorimetric card calibration: According to Table 1, the reagents in the formaldehyde detection kit were added according to the operation of Example 2, and the color displayed by the receiving pool in the kit was the color development chroma at the set concentration, according to which the liquid formaldehyde colorimetric card was developed.

[0101] The formaldehyde content in solutions of different concentrations was detected using the formaldehyde detection kit of Example 1, the absorbance was determined using a spectrophotometer at different color development times, and the color development stability curve was plotted according to the absorbance value, as shown in Figure 10 The results show that the color development conditions of the formaldehyde detection kit of Example 1 are simple and easy to operate, and the colorimetric chroma can be kept stable within 90 min after color development, overcoming the defects of most rapid test methods in color development.

[0102] The above embodiments are merely specific descriptions of feasible implementation manners of the utility model, and are for the convenience of the ordinary skilled in the art to understand and use the utility model. Those skilled in the art can obviously easily make various modifications to these embodiments, and apply the general principles described herein to other embodiments without creative labor. Therefore, the utility model is not limited to the above embodiments, and the utility model is not intended to limit the patent protection scope of the utility model, and any equivalent implementation or modification without departing from the utility model shall be included in the patent scope of the case.

Claims

1. A kit for the detection of formaldehyde, characterized in that, It includes a developer dripping device, which includes a receiving pool, a dripping pool, a dripping pool cover and a connecting rod; The receiving pool includes a base and a side wall arranged along the circumference of the base and extending upward, the base and the side wall forming a reaction chamber, and the reaction chamber is used to receive the liquid dripping from the dripping pool; The drip tank includes a base with an operating portion and a cup wall arranged along the circumference of the base and extending upward, wherein the base and the cup wall form a receiving cavity; The two ends of the connecting rod are respectively connected to the upper edge of the side wall of the receiving pool and the base of the dripping pool, so that the dripping pool is supported above the receiving pool; The drip pool cover includes an inner cover and an outer cover, wherein the inner cover is provided with a first adjustment portion penetrating the inner cover body, and the outer cover is provided with a second adjustment portion penetrating the outer cover body, wherein the first adjustment portion can adjust the speed at which the liquid in the accommodating chamber of the drip pool flows to the reaction chamber of the receiving pool in cooperation with the second adjustment portion; The lower surface of the inner cover includes an adapter portion with a preset depth, and is also provided with an operating rod extending downward. The length of the operating rod exceeds the preset depth of the adapter portion, and the operating rod penetrates the operating portion of the drip pool when the inner cover is downwardly covered on the drip pool.

2. The formaldehyde detection kit according to claim 1, characterized in that, The upper surface of the inner cover is provided with a matching portion that does not penetrate the inner cover body; The outer cover is also provided with a limit block and a positioning block that penetrates the outer cover body; the limit block is provided at the side end of the second adjustment part, and when the outer cover is downwardly covered on the inner cover, the limit block is passed through the first adjustment part; the positioning block is used to be positioned in the matching part of the inner cover when the outer cover is downwardly covered on the inner cover.

3. The formaldehyde detection kit according to claim 2, characterized in that, The first adjustment portion and the second adjustment portion are circular gaps, respectively located at 3 / 4 to 1 / 4 of the radius from the center point of the inner cover and the outer cover; The positioning block is a central buckle, and the inner cover and the outer cover are relatively rotated by the central buckle to adjust the exposed length of the gap and control the speed of liquid dripping.

4. The formaldehyde detection kit according to claim 1, characterized by The operating part of the drip pool is arranged at the center point of the bottom surface of the base for jack operation, and the operating part is a cross-shaped flexible connection or a circular film.

5. The formaldehyde detection kit according to claim 1, characterized in that, The circumference directions of the receiving pool and the drip pool are circular; The base and the side wall are integrally formed, and one or more slots and a guide portion are formed on one end of the side wall opposite to the base. The slots are spaced apart at the top of the side wall, and the guide portion protrudes outward from the surface of the side wall to facilitate the discharge of liquid from the reaction chamber. When there are two or more slots, the guide portion is provided between the two slots. The base of the drip pool is provided with a connecting groove corresponding to the card slot of the receiving pool, and the connecting groove does not penetrate the base. The connecting groove of the drip pool is selectively connected to the card slot of the receiving pool through a connecting support rod, so that the drip pool is supported above the receiving pool.

6. The formaldehyde detection kit according to claim 5, characterized in that, The upper part of the cup wall of the drip cell is provided with a fastening part which is the outer surface of the cup wall, and a step is arranged between the fastening part and the outer surface of the cup wall. The fitting part of the inner layer cover is connected with the fastening part of the drip cell by interference fit or threaded connection.

7. The formaldehyde detection kit according to claim 3, characterized in that, The width of the circular annular gap is 1-3 mm.

8. The formaldehyde detection kit according to claim 4, characterized in that, The size of the cross-shaped flexible joint is (2-8) mm×(2-8) mm. The diameter of the circular film is (2-8) mm.

9. The formaldehyde detection kit according to claim 5, characterized in that, The diameter of the base of the receiving cell is 2-5 cm, and the height of the side wall of the receiving cell is 1-3 cm. The diameter of the base of the drip cell is 2-5 cm, and the height of the cup wall of the drip cell is 1-5 cm.

10. The formaldehyde detection kit according to claim 1, characterized in that, The length of the operating rod is 1-3 cm. The cross section of the operating rod is circular with a diameter of 1-5 mm. The number of connecting struts is 2-4, and the length is 4-8 cm.

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