1、 Definition and scope of application
In this method, potassium persulfate (or nitric acid perchloric acid) is used as oxidant, unfiltered water sample is digested, and total phosphorus is determined by ammonium molybdate spectrophotometry.
Total phosphorus includes dissolved, granular, organic and inorganic phosphorus.
The method is applicable to surface water, groundwater, domestic sewage and industrial wastewater.
When the volume of water sample is 1ml and the diameter of 10 mm colorimetric tube is used, the detection limit of this method is 0.01mg/l, the lower limit of detection is 0.040mg/l and the upper limit of determination is 10.0mg/l (all calculated by P).
Potassium persulfate (or nitric acid perchloric acid) was used as oxidant and digested at high temperature to convert the phosphorus contained into orthophosphate. In acid medium, orthophosphate reacts with ammonium molybdate to form a blue complex. The total phosphorus value is determined by spectrophotometry.
The total phosphorus micro reflux test method developed by Shenzhen Changhong science and Technology Co., Ltd. (hereinafter referred to as "shenchanghong") is simple, rapid and economical in operation, with accurate and reliable test results. Shenchanghong can provide a complete analysis scheme of total phosphorus micro reflux test method, and users do not need to prepare their own total phosphorus reagents. The scheme includes total phosphorus analyzer, ds-16b / 20B / 25B / 36B digestion instrument and matched total phosphorus reagent. The total phosphorus reagent is used in combination with digester and total phosphorus analyzer. The analytical procedure is simple and convenient, which meets the requirements of national industry standards.
3、 Product features:
·There is no need to prepare total phosphorus reagent: the reagent prepared by a certain proportion of chemical components required for total phosphorus analysis can greatly save the preparation time of total phosphorus reagent;
·Time saving: the whole analysis process, including water sample digestion, colorimetric determination and other steps, saves time;
·Compact digestion device: ds-16b / 20B / 25B / 36B, a total phosphorus digester developed by shenchanghong, replaces the traditional device and can digest up to 16-36 water samples at the same time;
·The secondary pollution to the environment is small: the micro reflux method only needs a small amount of total phosphorus reagent, and the carefully designed total phosphorus reagent tube can prevent the volatilization of organic matters and the escape of samples, thus ensuring the safety of the digestion process;
·Simple operation and easy to learn: the operation guide with pictures and texts is convenient for mastering the analysis method of total phosphorus in a short time.
4、 Analysis steps of total phosphorus of shenchanghong by micro reflux method:
(1) Preparation of total phosphorus reagent and water sample
Put the reagents required for total phosphorus analysis into each total phosphorus pipe, add a proper amount of water sample according to the instructions, and then tighten the bottle cap.
(2) Water sample digestion
Put the digestion colorimetric tube that has been added with water sample and reagent into ds-16b / 20B / 25B / 36B, select appropriate digestion temperature and digestion time according to the requirements of reagent for hot reflux, after the digestion process, take out the total phosphorus test tube from ds-16b / 20B / 25B / 36B digester, cool it to room temperature, add reagent II, reagent III, and develop color for ten minutes for colorimetric determination.
(3) Colorimetric determination of total phosphorus
Shenchanghong's total phosphorus tester (tp-1a / tp-2a / cnp-301 / 301c / D / cnpn-401 / 401 / 401 / D / mulp-8c / pmulp-8, etc.) selects the corresponding total phosphorus test program in the main menu, without re establishing the standard curve, just put the digested total phosphorus reagent test tube into the instrument to read the total phosphorus value expressed in concentration units, and save the record results.
5、 Brief introduction of the analytical system of total phosphorus micro reflux method in shenchanghong
The total phosphorus micro reflux analysis system provided by shenchanghong includes the main machine of total phosphorus analyzer, digester and matching total phosphorus reagents.
(1) Instrument host: according to the needs of different customers, shenchanghong company can provide a variety of models of total phosphorus analyzer for the determination of total phosphorus.
(2) Ds-16b / 20B / 25B / 36B digester is a digestion device developed by shenchanghong. It can be used for the digestion of water samples such as total phosphorus, total chromium, total nitrogen and cod. The digestion time and temperature can be selected in the range of normal temperature - 200 ℃ and 1 - 9999 minutes respectively.