Abstract: The invention relates to an agent and a method for the dry chemical detection of lactoperoxidase in milk or dairy products. The method according to the invention is characterized by rapid execution thereof and said method has a high degree of sensitivity. The high detection sensitivity is achieved by adding iodide ions to the usual reagents.

Abstract: The invention relates to a dry chemical method and a test strip for determining calcium and magnesium in aqueous samples. Said test strip contains o-cresolphthalein complex (o-CPC; CAS Registry No. 2411-89-4) as a colour-causing reagent in a buffer system with a pH value of below 8.5. By using in particular an aqueous ethanolic imidazole buffer with a pH value of 6.75, conditions can be set up in such a way that the o-CPC has an identical molar sensitivity with respect to Ca and Mg. The total water hardness of aqueous samples can thus be easily determined.

Abstract: The invention relates to a method and test kit for detecting, in particular, free sulfite in aqueous samples. The sample is introduced into a closeable receptacle, is preferably rendered slightly acidic with acid, and a test strip is used to determine the sulfite content in the gas phase above the sample. The analysis can ensue visually or reflectometrically. The inventive test kit for carrying out the method comprises a closeable receptacle and a test strip for analyzing sulfite.

Abstract: The invention relates to a dry chemical method and a test strip for determining calcium and magnesium in aqueous samples. Said test strip contains o-cresolphthalein complex (o-CPC; CAS Registry No. 2411-894) as a colour-causing reagent in a buffer system with a pH value of below 8.5. By using in particular an aqueous ethanolic imidazole buffer with a pH value of 6.75, conditions can be set up in such a way that the o-CPC has an identical molar sensitivity with respect to Ca and Mg. The total water hardness of aqueous samples can thus be easily determined.

Abstract: The invention relates to a Karl-Fischer reagent, kit and a process for the determination of water with the aid of this reagent, which contains, instead of iodine, an approximately equimolar amount of iodine halides and salts of aromatic nitrogen-containing heterocyclic compounds.

Abstract: A pyridine-free Karl-Fischer reagent for the determination of water which comprises (a) a solvent solution containing sulfur dioxide and an amine in a Karl-Fischer reagent solvent, the amine being functionally equivalent to pyridine in a Karl-Fischer reagent, and (b) a titrating agent containing iodine in a Karl-Fischer solvent; the molar ratio of amine to sulfur dioxide being about 2:1 to about 1:1 and the reagent being essentially free of pyridine.

Abstract: A Karl-Fischer reagent useful in a process for the determination of water contains a pyridine substitute, sulfur dioxide and iodine. As the pyridine substitute, the reagent contains at least one compound from the group comprising the guanidines, amidines, imido-esters, isoureas, cyanamide, or salts thereof with a weak organic acid.

Abstract: A new Karl Fischer reagent contains as a pyridine substitute at least one compound of the general formula ##STR1## in which R.sup.1 and R.sup.2, which can be identical or different, =hydrogen or alkyl having 1-6 C atoms,R.sup.3 =alkyl having 1-6 C atoms,X=alkali metal ion or one equivalent of an alkaline earth metal ion,n=0 or a number from 1 to 4 andm=a number from 1 to 4.

Abstract: A Karl Fischer reagent useful in the determination of water, comprises sulfur dioxide, iodine and a salt which is a system compatible addition compound of a nitrogen-containing organic base having a pK.sub.b <10 with a weak aromatic carboxylic acid having a pK.sub.a >2.

Abstract: An essentially pyridine-free Karl Fischer reagent useful in the determination of water, comprises a dissolving agent containing sulfur dioxide and a pyridine substitute in a Karl Fischer solvent, and a titrating agent containing iodine in a Karl Fischer solvent, wherein the pyridine substitute is an alkali or alkaline earth metal benzoate or ammonia, and the reagent is essentially free of pyridine.