Volatile phenols in the application of integrated distillation apparatus

The automatic integrated distillation instrument is a new intelligent distillation treatment device, which integrates constant temperature heating, automatic control of distillation end point and circulation of cooling water, according to the operating procedures of laboratory distillation pretreatment Distillation is a very common and important pretreatment step in water quality test and food test The traditional distillation equipment, whose heating, distillation, condensation and receiving parts are independent and tedious to operate, often leads to distillation failure and affects work efficiency due to the lack of distillation end-point control The product adopts intelligent integrated design, and adopts precise temperature control, intelligent end-point control, built-in cooling water automatic cooling and reflux device and other technical means to realize the purpose of simple operation, automatic distillation, beautiful and practical, energy saving and consumption reduction It can be widely applied to the distillation operation of volatile phenol and ammonia nitrogen in water samples of environmental monitoring, water supply and drainage, disease prevention and control center and other fields In the field of food monitoring, the distillation operation of sulfur dioxide residue and the heavy distillation of phenol, etc 4-aminoantipyrine spectrophotometry is used for the determination of volatile phenol in water The experimental principle, scope of application, required reagents, interference elimination and result calculation refer to national standard hj503-2009 The application of the integrated distillation instrument in the experimental operation of volatile phenol 1 Plug in the power supply, check the distillation instrument, ensure that each heating hole can be heated normally, turn on the circulating water switch, check whether each interface leaks, so as to ensure the normal operation of the instrument 2 Take 250ml of sample into a 500ml full glass distillation flask, add 50ml of distilled water, add a few drops of methyl orange indicator, if the sample does not appear orange red, add phosphoric acid solution 3 Start heating distillation, when the distillate is close to 250ml, stop heating, and use distilled water to fix the volume to 250ml 4 Open the company's extractor and check whether the instrument can work normally After the inspection, transfer all 250ml distillate to the 500ml separating funnel provided by the company's extractor 5 Add 2.0ml buffer solution into the separating funnel, set the extraction intensity as 40Hz, time as 90s, retention time as 0, and extract once to mix the solution 6 Add 1.5ml of 4-aminoantipyrine solution, the extraction intensity, time and times remain unchanged, extract once, and mix the solution 7 Add 1.5ml of iron again, the extraction strength, time and times will not change, and the extraction will be conducted once, so as to make the reagent and water sample mix well Allow to stand for 10min 8 Add 10ml into the above separating funnel, set the extraction intensity as 35Hz, time as 60s, residence time as 30s, and extraction times as 3 times After setting, press the start key to start extraction After the extraction is completed, the layer is still 9 Dry the inner wall of the neck pipe of the separating funnel with dry absorbent cotton or filter paper, plug a small lump of dry absorbent cotton or filter paper in the neck pipe, pass the dry absorbent cotton or filter paper for the layer, discard the several drops of the extraction liquid that began to be filtered, and directly put the rest into the cuvette with the optical path of 20 mm 10 Measure the absorbance at 460nm as a reference 11 Blank test: the absorbance of distilled water is measured according to steps 4-10 instead of sample The blank and the sample were determined at the same time Note: 1 The buffer solution is ammonia water, so the extraction strength should not be too high when it is evenly mixed Under the appropriate strength, it should be fully mixed evenly, otherwise the blank will be too large 2 The liquid should be put into drops instead of lines.