CN106053462A - Method for measuring trace thallium in water - Google Patents

Abstract

The invention discloses a method for measuring trace thallium in water. The method includes following steps: (1), preparing a thallium standard solution; (2), demarcating a sodium EDTA standard titration solution; (3), setting a sampling amount; (4), gathering foamed plastic of a sample; (5), analyzing the sample; (6), calculating thallium content in the sample. Polyurethane foam is adopted to separate gathered thallium, desorption is realized through water bath, and an automatic photometric titrator is utilized to measure trace thallium in the water. The method is simple, quick, high in accuracy, low in instrument investment and using cost, low in detection limit and capable of meeting detection work and study needs of people.

Description

The assay method of Determination of Trace Thallium in a kind of water

Technical field

The present invention relates to the easy assay method of Determination of Trace Thallium in a kind of water, the mensuration side of Determination of Trace Thallium in a kind of water Method.

Background technology

Thallium (Thallium), as a Heavy Metallic Elements, belongs to hypertoxic type, has accumulative, be strong neurotoxic substance, Under normal circumstances, the minimum lethal dose of 70kg adult is 50-80mg, and every day, the highest thallium allowed intake to be 2mg, if environment is situated between In matter, thallium content is near or above its threshold value, it is possible to health and environmental danger.Therefore, thallium is environmental monitoring One of important indicator, the most relatively conventional detection method or means have inductively coupled plasma mass spectrometry (ICP-MS), electricity Sense coupled plasma-atomic emission spectrometry, GFAAS etc., these detection methods are large-scale owing to using Instrument and equipment, can obtain relatively low detection limit, is suitable for trace and the trace analysis of thallium, and shortcoming is the input of instrument and equipment and makes With relatively costly, popularization and application is restricted.Traditional titrimetry is generally used for macroanalysis, is not suitable for trace and trace Analyzing, the titrimetry of thallium also has EDTA titrimetry, but is only applicable to the mensuration of high concentration thallium solution, applicable mensuration concentration For: more than 4mg/ml.

Summary of the invention

In order to overcome the defect of above-mentioned prior art, the present invention provides the assay method of Determination of Trace Thallium in a kind of water, particularly Polyurethane foam separation-automatic Photometric Titration the method for a kind of improvement measures the method for Determination of Trace Thallium in water.Thallium solution can be entered by it Row trace and trace analysis.

The technical scheme is that the assay method of Determination of Trace Thallium in a kind of water, comprise the steps:

(1) thallium standard solution preparation: weigh content > Thallic oxide of 99.99% is placed in beaker, covers table ware, slow Slowly add concentrated nitric acid, dissolution in low temperature, drive away nitrogen oxide, take off and be cooled to room temperature, wash surface plate and wall of cup with water, move into In volumetric flask, it is diluted with water to scale, mixing.

(2) demarcation of disodiumedetate standard titration solution: disodiumedetate standard titration solution is dense Degree is 0.005mol/L, pipettes three parts of thallium standard solution, it is desirable in every part of pipetted thallium mark liquid, thallium total amount is 2.5～10mg, point It is not placed in 200mL titration cup, adds 50～120mL water and 0.20～0.75mL xylenol orange indicator, be neutralized to alkali liquor Redness, adds 2～10mL acetic acid-sodium acetate buffer solution, is put in by titration cup on automatical potentiometric titrimeter titration platform, inserts ripple The luminosity electrode of a length of 574nm, sets titration parameters, runs titration procedure, molten with disodiumedetate standardized titration Drop is fixed, and the disodiumedetate standard titration solution volume consumed during titration end-point is designated as Vs,

The concentration of disodiumedetate standard titration solution is calculated as follows:

$C_{{\mathrm{Na}}_{2}EDTA}=\frac{N}{M\×Vs}$

In formula:

Disodiumedetate standard titration solution concentration, unit is mol/L,

N pipettes the quality of thallium, and unit is mg,

The Na consumed during Vs titration end-point₂EDTA standard titration solution volume, unit is mL,

M is the molal weight of thallium, and unit is g/mol, M=204.38,

(3) sample volume: pipetting corresponding test solution in conical flask according to the content of thallium in sample, volume is less than 70mL, during as exceeded, need to heat in advance and be concentrated into below 70mL,

(4) Plastic Foam Preconcentration of sample: add hydrogen peroxidase 10 .5～5mL, iron salt solutions 0.5～4mL, add water to 100ml, adds the foam plastics removing bubble in advance through water-soaked side by side, vibration 45～120min in agitator, takes out foam Plastics also repeatedly extrude, rinse, extract, and are placed in by foam plastics in the titration cup filling 20～50mL dust technology, and boiling water bath adds Heat 60～120min, washes out foam with the dust technology of heat while hot, and washing liquid is incorporated in former titration cup,

(5) analysis of sample: be put in by titration cup on automatical potentiometric titrimeter titration platform, inserting wavelength is the light of 574nm Degree electrode, sets titration parameters, runs titration procedure, titrates with disodiumedetate standard titration solution, and titration is eventually The disodiumedetate standard titration solution volume consumed during point is designated as ν,

(6) calculating of thallium content in sample:

The content of thallium is with mass concentration w_TlMeter, unit is ug/mL, is calculated as follows:

$w_{Tl}=\frac{(v-v_0)\·c\·M}{v_1}\×1000$

In formula:

The disodiumedetate standard titration solution volume consumed during ν titration end-point, unit is mL,

ν₀The disodiumedetate standard titration solution volume that blank solution consumes, unit is mL,

C disodiumedetate standard titration solution concentration, unit is mol/L,

v₁The volume of test solution, unit is mL,

M is the molal weight of thallium, and unit is g/mol, M=204.38,

In step (1), thallium concentration of standard solution is 500～2000ug/mL.

Concentrated nitric acid solution in step (1), nitric acid is 1:1～2:1 with the ratio of water.

In step (2), alkali liquor is ammonia.

In step (4), foam plastics is cellular (foamed) polyurethane, polyester sponge, polyethers or sponge.

In step (4), iron salt solutions is iron chloride or ferrum sulfuricum oxydatum solutum.

In step (4), dilute nitric acid solution is the ratio=1:99 of nitric acid and water.

The present invention has the prominent advantages that:

Use method of the present invention that thallium solution can carry out trace and trace analysis, and instrument puts into and uses into This is low, method is easy.

Detailed description of the invention

Below in conjunction with embodiment, technical scheme is described further.

Embodiment 1

An example of the assay method of Determination of Trace Thallium in water of the present invention, is trace in certain Tailings Dam surface water water sample The mensuration of thallium, comprises the steps:

(1) the polyurethane foam enriching section of sample: take sample 50mL, adds hydrogen peroxide 2mL, iron salt solutions 2mL, adds Water, to 100ml, adds the foam plastics removing bubble in advance through water-soaked side by side, and vibrate in agitator 90min, takes out foam plastic Material also repeatedly extrudes, rinses, extracts, and is placed in by foam plastics in the titration cup filling 30mL dust technology, and boiling water bath heats 90min, washes out foam with the dust technology of heat while hot, and washing liquid is incorporated in former titration cup；

(2) the photometric titration process of sample: be put in by titration cup on automatical potentiometric titrimeter titration platform, inserting wavelength is The luminosity electrode of 574nm, sets titration parameters, titrates with disodiumedetate standard titration solution, during titration end-point The disodiumedetate standard titration solution volume consumed is designated as ν；

(3) calculating of thallium content: the content of thallium is with mass concentration w_TlMeter, unit is ug/mL, is calculated as follows:

$w_{Tl}=\frac{(v-v_0)\·c\·M}{v_1}\×1000$

In formula:

The disodiumedetate standard titration solution volume consumed during ν titration end-point, unit is mL,

ν₀The disodiumedetate standard titration solution volume that blank solution consumes, unit is mL,

C disodiumedetate standard titration solution concentration, unit is mol/L,

v₁The volume of test solution, unit is mL,

M examination is the molal weight of thallium, and unit is g/mol, M=204.38.

Table 1 lists method described above and measures the result of water sample three times.

Table 1 method described above measures water sample three times, and result is as follows:

The result of table 1 shows, using method of the present invention, water sample thallium-containing quantity is 5.305ug/ml, measures knot three times Really deviation is little, and result is accurate.

Claims (7)

1. the assay method of Determination of Trace Thallium in a water, it is characterised in that the method comprises the steps:

(1) thallium standard solution preparation: weigh content > Thallic oxide of 99.99% is placed in beaker, cap upper surface ware, slowly Add concentrated nitric acid, dissolution in low temperature, drive away nitrogen oxide, take off and be cooled to room temperature, wash surface plate and wall of cup with water, move into and hold In measuring bottle, it is diluted with water to scale, mixing,

(2) demarcation of disodiumedetate standard titration solution: disodiumedetate standard titration solution concentration is 0.005mol/L, pipettes three parts of thallium standard solution, it is desirable in every part of pipetted thallium mark liquid, thallium total amount is 2.5～10mg, puts respectively In 200mL titration cup, add 50～120mL water and 0.20～0.75mL xylenol orange indicator, be neutralized to redness with alkali liquor, Adding 2～10mL acetic acid-sodium acetate buffer solution, be put in by titration cup on automatical potentiometric titrimeter titration platform, inserting wavelength is The luminosity electrode of 574nm, sets titration parameters, runs titration procedure, drips with disodiumedetate standard titration solution Fixed, the disodiumedetate standard titration solution volume consumed during titration end-point is designated as Vs,

The concentration of disodiumedetate standard titration solution is calculated as follows:

$C_{{\mathrm{Na}}_{2}EDTA}=\frac{N}{M\×Vs}$

In formula:

Disodiumedetate standard titration solution concentration, unit is mol/L,

N pipettes the quality of thallium, and unit is mg,

The Na consumed during Vs titration end-point₂EDTA standard titration solution volume, unit is mL,

M is the molal weight of thallium, and unit is g/mol, M=204.38,

(3) sample volume: pipetting corresponding test solution in conical flask according to the content of thallium in sample, volume is less than 70mL, during as exceeded, need to heat in advance and be concentrated into below 70mL,

(4) Plastic Foam Preconcentration of sample: add hydrogen peroxidase 10 .5～5mL, iron salt solutions 0.5～4mL, add water to 100ml, Add the foam plastics removing bubble in advance through water-soaked side by side, vibration 45～120min in agitator, take out foam plastics also Repeatedly extrude, rinse, extract, foam plastics is placed in the titration cup filling 20～50mL dust technology, boiling water bath heating 60～ 120min, washes out foam plastics with the dust technology of heat while hot, and washing liquid is incorporated in former titration cup,

(5) analysis of sample: be put in by titration cup on automatical potentiometric titrimeter titration platform, inserts the luminosity electricity that wavelength is 574nm Pole, sets titration parameters, runs titration procedure, titrates with disodiumedetate standard titration solution, during titration end-point The disodiumedetate standard titration solution volume consumed is designated as ν,

(6) calculating of thallium content in sample:

The content of thallium is with mass concentration w_TlMeter, unit is that ug/mL represents, is calculated as follows:

$w_{Tl}=\frac{(v-v_0)\·c\·M}{v_1}\×1000$

In formula:

The disodiumedetate standard titration solution volume consumed during ν titration end-point, unit is mL,

ν₀The disodiumedetate standard titration solution volume that blank solution consumes, unit is mL,

C disodiumedetate standard titration solution concentration, unit is mol/L,

v₁The volume of test solution, unit is mL,

M is the molal weight of thallium, M=204.38, and unit is g/mol.

The assay method of Determination of Trace Thallium in water the most according to claim 1, it is characterised in that thallium standard solution in step (1) Concentration is 500～2000ug/mL.

The assay method of Determination of Trace Thallium in water the most according to claim 1, it is characterised in that concentrated nitric acid solution in step (1), Nitric acid is 1:1～2:1 with the ratio of water.

The assay method of Determination of Trace Thallium in water the most according to claim 1, it is characterised in that in step (2), alkali liquor is ammonia.

The assay method of Determination of Trace Thallium in water the most according to claim 1, it is characterised in that in step (4), foam plastics is Cellular (foamed) polyurethane, polyester sponge, polyethers or sponge.

The assay method of Determination of Trace Thallium in water the most according to claim 1, it is characterised in that in step (4), iron salt solutions is Iron chloride or ferrum sulfuricum oxydatum solutum.

The assay method of Determination of Trace Thallium in water the most according to claim 1, it is characterised in that dilute nitric acid solution in step (4) Ratio=1:99 for nitric acid Yu water.