DE2809475C2 - Means and methods for the detection of aldehydes - Google Patents

Description

The invention relates to a means for the detection and semi-quantitative determination of aldehydes with Help of 4-amino-3-hydrazino-5-mercapto-l, 2,4-triazole and a process for the preparation of this agent.

It is known that 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole is a very sensitive and specific color reagent for aldehydes (Chem. Comm. 1970, 1719). This creates the purple-colored 6-mercapto-3-substituted-s-triazo! O [4,3-b] -s-tetrazine, the substituent in the 3-position originating from the aldehyde.

The detection of aldehydes is becoming increasingly important, as aldehydes are used in many disinfectants are contained as active substances and have also been proven again in great dilution Need to become. Also the identification and determination of compounds that are converted into an aldehyde can be mentioned here, e.g. B. the determination of sorbic acid by oxidative cleavage and detection of the malondialdehyde formed.

However, the known method of determination has the decisive disadvantage that a Well-equipped laboratory with spectrophotometer and trained staff are necessary.

The invention was therefore based on the object of providing a means for the detection of aldehydes that can be used by anyone independent of a laboratory.

According to the invention, the object was achieved by an absorbent carrier containing the chromogen, the is additionally impregnated with thiourea and peroxydisulfate, dissolved.

The subject matter of the invention further comprises a process for the production of this agent, which thereby is characterized in that an absorbent carrier with 4-amino-S-hydrazino-S-mercapto-1,2,4-triazole, thiourea and impregnating peroxydisulfate.

Another object of the invention is the use of this agent for the detection and semi-quantitative determination of aldehydes in liquids.

Surprisingly, it has been shown that uncolored zero values were only delivered in Gefat, even after longer periods Storage time of the stick. It has thus become possible for the first time to use a rod for the detection of aldehydes or to make available of convertible compounds into aldehydes, with the outside of a Laboratory aldehydes can be detected by anyone. That is especially in environmental protection important where analyzes often have to be carried out on site.

ίο The preparation of the agent according to the invention takes place in such a way that an absorbent carrier is soaked in succession with two different solutions; It is of course necessary that the absorbent carrier be dried between the impregnations will.

The impregnation solution I contains about 0.1-2% by weight of 4-amino-3-hydrazino-5-mercapto-l, 2,4-triazole and 0.1-10% by weight thiourea in 10% aqueous ammonia. The soaking solution II contains about 0.05-5 % By weight of a peroxydisulfate and 10% by weight of dimethyl sulfoxide in water. As peroxydisulfates are suitable especially sodium, potassium and ammonium peroxydisulphate, especially potassium peroxydisulphate.

As absorbent carriers it is possible to use all those which are usually used for similar detection reactions in the Use are. The most common is the use of filter paper, but other absorbent materials can also be used Cellulose or plastic products are used. The absorbent carrier, preferably filter paper, are impregnated one after the other with impregnation solutions in a manner known per se. The soaked papers can either be cut as such into manageable strips, or they can be cut into preferably square strips Zones are processed, which in turn in a known manner on plastic films, paper or metal strips can be glued on or on or sealed.

Since the sensitivity of the aldehyde detection according to the invention with increasing alkali concentration increases, the solution to be tested is preferably first mixed with the same amount of 10% sodium hydroxide solution offset. To detect the aldehyde, these test strips are then alkaline in the one to be tested set solution immersed so that the test zone is fully wetted. The color changes in the presence of aldehydes Test zone purple. This color is compared after about 30 seconds with a color scale and the aldehyde concentration the solution can be read with ease. With this semi-quantitative proof are z. B. clear shades of violet between 10, 20, 30.50 and 100 mg / 1 (or ppm.) Formaldehyde perceptible.

example

Filter paper (No. 2316 from Schleicher & Schüll) is soaked with solution I, dried and then soaked with solution II and dried again. The impregnated filter paper thus obtained becomes small in size

ne reaction zone with a non-colored zero value can be obtained. Detection sticks in which the reaction zone was only impregnated with 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole showed a clearly positive reaction, especially after prolonged storage, even if no aldehyde was present in the solution investigated. Only the addition of thiourea and peroxidisul uuvj aui

itv- yuauiaic vxjii tiwa ~ j λ * j hihi gc3 \ »iiiui plastic strips of 6 χ 60 mm glued to the lower end.

Soaking solution I contains:

1 g4-amino-3-hydrazino-5-mercapto-1,2,4-triazole 1 g thiourea

100 ml of 10% ammonia

Soaking solution II contains:

0.5 g of potassium peroxydisulfate

10 ml of dimethyl sulfoxide

90 ml of water

After immersion in a solution, the test stick shows the same volume of 10% sodium hydroxide solution was added, a further 0.0005 mg of formaldehyde / 100 ml due to the blue-violet color.

With the same test stick, 0.005 mg acetaldehyde / 100 ml can still be determined by red-violet coloration or 0.5 mg benzaldehyde / 100 ml can be clearly demonstrated by the brown-violet color.

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Claims (3)

Patent claims: 1. Means for the detection of aldehydes with the help of -i-Amino-S-hydrazino-S-mercapto-1,2,4-triazole, characterized by an absorbent, the chromogen-containing carrier, which is additionally impregnated with thiourea and peroxydisulfate. 2. A method for producing the agent according to claim 1 "characterized in that an absorbent carrier with 't-amino-S-hydrazino-S-mercapto-1,2,4-triazole, Thiourea and peroxydisulfate is impregnated. 3. Use of the agent according to claim 1 for detection and for semi-quantitative determination of aldehydes in liquids.