CN1201906A

CN1201906A - Preparation of standard sulfide

Info

Publication number: CN1201906A
Application number: CN 97105912
Authority: CN
Inventors: 于荣云; 马克胜
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-06-11
Filing date: 1997-06-11
Publication date: 1998-12-16
Anticipated expiration: 2017-06-11
Also published as: CN1107867C

Abstract

A standard sulfide substance used for water monitor in environmental protection is prepared from deionized aseptic water as solvent and Na2S.9H2O as solute, and features high stability, long storage period (at least one year), high accuracy (less than +/- 3%) and uniformity, and low cost. It can be used for more monitor method and the calibration of test instruments.

Description

A kind of preparation method of standard sulfide

The invention provides the preparation method of standard sulfide in a kind of environment monitoring, be used for the monitoring of water and sulfides from wastewater content.

Sulfide is must survey project in the water of national regulation and the effluent monitoring project.But because sulfide is a kind of easily oxidized, extremely unsettled material, add the influence of many disturbing factors, do not develop more satisfactory standard sulfide so far both at home and abroad as yet.Like this, sulfide monitoring department just can't calibrate instrument, can't estimate method of testing, the Quality Control personnel just can't carry out various quality assurances and quality control work to sulfide monitoring personnel, and metrological service just can't carry out China Metrology Accreditation work to sulfide monitoring personnel.In a word, do not have desirable standard sulfide, just can't carry out the transmission of sulfide value and trace to the source, this has just directly influenced the control and the environmental protection of sulfide emission amount.Standard sulfide all is to use Na at present ₂S9H ₂The O preparation.Still there is not the pure Na of top grade both at home and abroad ₂S9H ₂O sells, and sodium sulphide this is also oxidized easily in depositing process, generate multiple sulfocompounds such as sulphite, sulfate, thiosulfate, be mixed with solution after, oxidized speed is faster.Because its instability has just produced error with the iodimetric titration demarcation with the methylene blue method timing signal.For improving the stability of standard solution, there is the people in standard solution, to add EDTA, only stable the preservation 6 days.Someone adds ascorbic acid in standard solution, it is reported can stablize 3 months.Domestic at present unique on sale be the development of Liaoning Environmental Monitoring station with zinc sulphide solution as the sulfide standard solution, it is to make solvent with the anaerobic carbon dioxide-free water, Na ₂S9H ₂O makes solute, uses the zinc acetate used as stabilizers, and its stable storage life is only more than two months, and accuracy is lower.The applicant once made overtesting with this standard substance, blowing preceding is 92% of true value with the iodometric determination result, the back measurement result of blowing is 2.7 times of true value, relative error is 167%, and homogeneity is relatively poor, owing to add the zinc acetate stabilizing agent, therefore turbid phenomenon occurs in the cryopreservation process, just a large amount of white granular sediments and suspension occur when especially dilution back and air blowing are reclaimed, thereby had a strong impact on the accuracy of monitoring result.In addition, this standard substance manufacturing process complexity, and added other materials, be easy to produce more interference.

The preparation method who the purpose of this invention is to provide a kind of standard sulfide is with the stability, uniformity that improves standard sulfide, the accuracy of monitoring result.

The present invention is achieved in that a kind of preparation method of standard sulfide, uses Na ₂S9H ₂The preparation of O crystal is made distilled water with tap water with water still, with the yin and yang resin ion-exchanger distilled water is made deionized water again, deionized water is sub-packed in container is built in the high-pressure sterilizing pot, at 121～130 ℃ of temperature, 1.1～1.3kg/cm ²The pressurize sterilization was cooled off after 25～38 minutes under the pressure, and making no ion does not have mattress water, according to compound concentration and volume, accurately took by weighing and wash down outer year impurity, blots the outer Na that carries moisture ₂S9H ₂The expense of O crystal can make standard sulfide with no ion sterilized water with the volume that its dissolving is settled to required preparation.

The standard sulfide that adopts said method to make is because Na ₂S9H ₂O is dissolved in the no ion aseptic aqueous solution, under alkali condition, with Na ⁺, S ^2-The form of ion exists wherein.In the ampoule bottle of strict seal, be not subjected to the interference of various microorganisms, zwitterion and other various organic and inorganic materials, therefore theoretically, S in the solution ^2-Content should be stable.Through long-term experimental observation, its pot-life can be more than 1 year and highly stable, carries out replicate determination through grab sample repeatedly between storage life, in its group, measure as a result relative error, relative deviation between group all≤± 3%.The accuracy of this standard substance is also very high, and this material preceding to blowing respectively, the same concentration in back of blowing is measured, and the relative error between its result and the true value all≤± 3%.The homogeneity of this standard substance is also fine, no matter during preservation or when mark-on blow to reclaim, the performance characteristic of this standard substance be transparent, do not have precipitation, do not have suspend, muddy phenomenon.To 0.8mg/l (S ^2-) accurate material dilution with eight parallel samples of iodometric determination, its measurement result standard deviation be-0.7%, accuracy, reappearance are very good, this method technology is simple, makes easily, and is easy to preserve and transports.

A kind of concrete grammar of the present invention below is described.

With water still tap water is made distilled water, with the ionized water interchanger distilled water is made deionized water again, the deionized water branch is packed into seal in the triangular flask of 500ml or the reagent bottle, place high-pressure sterilizing pot, at 121～130 ℃ of temperature, 1.1～1.3kg/cm ²The pressurize sterilization is 25～38 minutes under the pressure, and can make no ion after the cooling does not have mattress water.Choose a certain amount of Na ₂S9H ₂The O crystal places on the two-layer sterile gauze, does not have mattress water with the no ion that makes and washes down Na fast ₂S9H ₂After the O crystal carries impurity outward, rapidly with Na ₂S9H ₂The O crystal moves on on three layers of aseptic filter paper, and then covers three layers of no mattress filter paper, blots Na immediately ₂S9H ₂The O crystal carries moisture outward.According to compound concentration and volume, accurately take by weighing Na ₂S9H ₂The expense of O crystal, the volume that is settled to required preparation with no ion sterilized water dissolving can make standard sulfide.

Whole process of preparation all should be carried out under aseptic condition.

Deionized water is when sterilization, and temperature, pressure are high more, and the sterilization required time is short more, otherwise then long more.And the weight of no dried up son is big more in the container, and sterilization time is long more.

Claims

A kind of preparation method of standard sulfide uses Na ₂S9H ₂The preparation of O crystal, it is characterized in that, tap water is made distilled water with water still, with the yin and yang resin ion-exchanger distilled water is made deionized water again, deionized water is sub-packed in container is built in the high-pressure sterilizing pot, at 121～130 ℃ of temperature, 1.1～1.3Kg/cm ²The pressurize sterilization is after 25～38 minutes under the pressure, and cooling makes no ion sterilized water, according to compound concentration and volume, accurately takes by weighing and wash down outer year impurity, blots the outer Na that carries moisture ₂S9H ₂The expense of O crystal can make standard sulfide with sterile deionized water with the volume that its dissolving is settled to required preparation.