阅读说明：本技术 一种同时检测三氯化铁中痕量As、Pb、Cd、Zn、Cr、Co、V元素含量的方法 (Method for simultaneously detecting contents of trace As, Pb, Cd, Zn, Cr, Co and V elements in ferric trichloride ) 是由 杨柳荫 车莹 何开景 钱藏藏 曾慧 于 2020-04-16 设计创作，主要内容包括：本发明公开了一种同时检测三氯化铁中痕量As、Pb、Cd、Zn、Cr、Co、V的方法,包括以下步骤：(1)样品前处理：称取2-20g三氯化铁样品,加入5-50mL纯盐酸、适量氧化剂,加热至样品溶解和氯化亚铁氧化完全,将待测样品转移至分液漏斗中,加入10-30mL乙酸丁酯,将Fe<Sup>3+</Sup>萃取干净,取水层,水浴富集至5-20mL,将样品溶液转移至10mL或25mL容量瓶中,定容摇匀,同时做空白；(2)选择元素谱线；(3)绘制标准曲线；(4)检测试样：将试样溶液通过进样系统引入ICP-OES,测定各元素所对应的发射光强度,根据标准曲线确定各元素含量。本发明方法所得各元素标准曲线线性关系良好,检出限低,对各元素含量的测定具有高的准确度和精密度,可用于标准样品和生产产品的分析。(The invention discloses a method for simultaneously detecting trace As, Pb, Cd, Zn, Cr, Co and V in ferric trichloride, which comprises the following steps of (1) sample pretreatment, weighing 2-20g of ferric trichloride sample, adding 5-50m L pure hydrochloric acid and a proper amount of oxidant, heating until the sample is completely dissolved and ferrous chloride is completely oxidized, transferring the sample to be detected into a separating funnel, adding 10-30m L butyl acetate, and carrying out Fe detection 3+ Extracting, collecting a water layer, enriching to 5-20m L in water bath, transferring a sample solution into a 10m L or 25m L volumetric flask, fixing the volume, shaking up, and simultaneously making blank, (2) selecting an element spectral line, (3) drawing a standard curve, (4) detecting a sample, namely introducing the sample solution into ICP-OES through a sample introduction system, measuring the emission light intensity corresponding to each element, and determining the content of each element according to the standard curveThe obtained standard curve of each element has good linear relation and low detection limit, has high accuracy and precision for measuring the content of each element, and can be used for analyzing standard samples and produced products.)

1. A method for simultaneously detecting the contents of trace As, Pb, Cd, Zn, Cr, Co and V elements in ferric trichloride is characterized by comprising the following steps:

(1) sample pretreatment, namely weighing 2-20g of sample in a beaker with the thickness of 100m L, adding 5-50m L of high-grade pure hydrochloric acid and a proper amount of oxidant, heating until the sample is dissolved and ferrous chloride in the sample is completely oxidized, transferring the sample to be detected to a separating funnel, adding 10-30m L of butyl acetate, extracting for 2-5 times, and adding Fe³⁺Extracting, collecting water layer, concentrating in water bath to 5-20m L, transferring sample solution into 10m L or 25m L volumetric flask, adding distilled water to constant volume, shaking, and making blank;

(2) selecting an element spectral line: selecting the optimal analysis spectral line of each element according to the matrix composition and impurity components of the sample;

(3) drawing a standard curve: preparing standard solutions of As, Pb, Cd, Zn, Cr, Co and V, introducing the standard solutions into an inductively coupled plasma emission spectrometer (ICP-OES) through a sample introduction system, measuring the emission intensity of each element under the optimal analysis spectral line, and drawing a standard curve;

(4) detecting a sample: introducing the sample solution obtained in the step (1) into an inductively coupled plasma emission spectrometer through a sample introduction system, measuring the intensity of emitted light corresponding to As, Pb, Cd, Zn, Cr, Co and V, and determining the content of each element according to a standard curve;

wherein, the working conditions of the inductively coupled plasma emission spectrometer in the steps (3) and (4) are that the radio frequency power is 950-.

2. The method of claim 1, wherein: the oxidant in the step (1) comprises superior pure nitric acid, hydrogen peroxide and sodium chlorate.

3. The method of claim 1, wherein: the temperature of the water bath in the step (1) is 100 ℃.

4. The method of claim 3, wherein: the distilled water in the step (1) is first-grade water meeting the regulation in GB/T6682.

5. The method of claim 1, wherein: the optimal spectral lines of the elements in the step (2) are as follows: 193.759nm for As, 220.3nm for Pb, 214.43nm for Cd, 213.856nm for Zn, 267.72nm for Cr, 228.616nm for Co and 309.311nm for V.

6. The method of claim 1, wherein the As, Pb, Cd, Zn, Cr, Co and V standard solutions prepared in step (3) have concentration gradients of 0 mg/L, 0.006 mg/L, 0.03 mg/L, 0.15 mg/L, 0.6 mg/L and 1.5 mg/L.

7. The method of any one of claims 1-6, wherein: the inductively coupled plasma emission spectrometer used was an ICAP7000 type full spectrum direct reading inductively coupled plasma emission spectrometer from Siemer Feishale, USA.

Technical Field

The invention belongs to the field of element analysis, relates to a method for simultaneously detecting the contents of trace As, Pb, Cd, Zn, Cr, Co and V elements in ferric trichloride, and particularly relates to a method for simultaneously detecting the contents of trace As, Pb, Cd, Zn, Cr, Co and V elements in ferric trichloride by using an inductively coupled plasma emission spectrometer.

Background

Ferric trichloride is used as a water treatment agent and a medical intermediate, and heavy metal elements which are harmful to human bodies, organisms, water bodies and the like in the ferric trichloride need to be limited and detected. For the test of Co and V in ferric chloride, at present, no unified detection method and standard exist in China, but the test of As, Pb, Cd, Zn and Cr in the latest version of GB/T4482-2018 water treatment agent ferric chloride requires two instruments of an atomic absorption spectrophotometer and an atomic fluorescence spectrophotometer, and when a sample tests each element, a standard solution and the sample need to be prepared separately, so that the operation is complex, the steps are long, the time and the labor are consumed, and the efficiency is low, therefore, the development of a new test method is necessary.

The ICP-OES has low detection limit, small matrix effect, high precision, high sensitivity and wide linear range (up to 10)⁵) And various elements can be simultaneously measured, and the method can be developed to simultaneously detect various trace heavy metals in the ferric trichloride as a conventional laboratory analytical instrument. When trace elements such As As, Pb, Cd, Zn, Cr, Co, V and the like in the ferric trichloride are directly tested, due to the fact that the content of an iron matrix is too high and the content of the trace elements is too low, spectral interference phenomena such As high background, disconnection of background, high main peak, main peak drift, main peak disconnection and the like can be caused during testing, so that a large deviation occurs in a testing result, trace elements such As As, Pb, Cd, Zn, Cr, Co, V and the like in the ferric trichloride cannot be directly tested, the iron matrix needs to be separated, and weight-loss metals cannot be introduced or damaged in the separation process.

Disclosure of Invention

The invention aims to provide a method for simultaneously detecting the contents of trace As, Pb, Cd, Zn, Cr, Co and V elements in ferric trichloride by using an inductively coupled plasma emission spectrometer (ICP-OES), and the method has higher accuracy and precision.

In order to solve the technical problems, the invention adopts the following technical scheme:

a method for simultaneously detecting the contents of trace As, Pb, Cd, Zn, Cr, Co and V elements in ferric trichloride by utilizing ICP-OES comprises the following steps:

(1) sample pretreatment, namely weighing 2-20g of sample in a beaker with the thickness of 100m L, adding 5-50m L of high-grade pure hydrochloric acid and a proper amount of oxidant, heating until the sample is dissolved and ferrous chloride in the sample is completely oxidized, transferring the sample to be detected to a separating funnel, adding 10-30m L of butyl acetate, extracting for 2-5 times, and adding Fe³⁺Extracting, collecting water layer, concentrating in water bath to 5-20m L, transferring sample solution into 10m L or 25m L volumetric flask, adding distilled water to constant volume, shaking, and making blank;

(2) selecting an element spectral line: selecting the optimal analysis spectral line of each element according to the matrix composition and impurity components of the sample;

(3) drawing a standard curve: preparing standard solutions of As, Pb, Cd, Zn, Cr, Co and V, introducing the standard solutions into an inductively coupled plasma emission spectrometer (ICP-OES) through a sample introduction system, measuring the emission intensity of each element under the optimal analysis spectral line, and drawing a standard curve;

(4) detecting a sample: introducing the sample solution obtained in the step (1) into an inductively coupled plasma emission spectrometer through a sample introduction system, measuring the intensity of emitted light corresponding to As, Pb, Cd, Zn, Cr, Co and V, and determining the content of each element according to a standard curve;

wherein, the working conditions of the inductively coupled plasma emission spectrometer in the steps (3) and (4) are that the radio frequency power is 950-.

The purity of the oxidants such as hydrochloric acid and nitric acid added in the step (1) of the method is superior grade purity; preferably, the distilled water is primary water according to the specification in GB/T6682. The mass of the sample in the step (1) is 2-20g, and the sample is determined according to the content of impurity elements in the sample, less mass is selected to be weighed when the impurity content is high, and more samples are weighed when the impurity element content is low; due to Fe³⁺Must be complexed to synthesize [ FeCl ] under strong acid condition₄]^-Can be extracted by butyl acetate, and the lower the proportion of the sample to the hydrochloric acid is, the more favorable the dissolution and extraction of the sample are; the smaller the ratio of the amount of sample and hydrochloric acid to the amount of butyl acetate, the more favorable the Fe³⁺Is extracted to be clean; due to Fe²⁺The iron element in the sample is difficult to be extracted, and nitric acid, hydrogen peroxide, sodium chlorate and other oxidants are required to be added before extraction to completely oxidize ferrous chloride; because a large amount of high-concentration hydrochloric acid is added, in order to protect ICP-OES and enrich a sample, the sample needs to be evaporated and concentrated, the volatilization of impurity elements is reduced by selecting a water bath mode, and the water bath with the temperature of 100 ℃ is preferred to shorten the detection time.

In the step (2) of the method, because the trace elements are detected, spectral lines with high sensitivity, small interference, low background and good linear coefficient are selected as analysis spectral lines in the spectral lines recommended by the instrument, and the optimal spectral lines of the elements are as follows: 193.759nm for As, 220.3nm for Pb, 214.43nm for Cd, 213.856nm for Zn, 267.72nm for Cr, 228.616nm for Co and 309.311nm for V.

The concentration gradients of each element selected in the standard solution prepared in step (3) of the method are 0 mg/L, 0.006 mg/L, 0.03 mg/L, 0.15 mg/L, 0.6 mg/L and 1.5 mg/L.

In order to achieve the purpose of measuring trace elements in the ferric trichloride sample, the radio frequency power of 1150W, the pump speed of 50r/min, the auxiliary gas flow of 0.5L/min, the flow of 0.65L/min, the observation height of 12cm, the integration time of 30S and other key instrument working parameters are preferably selected in the test, so that the detection accuracy and precision are ensured.

The invention utilizes butyl acetate to react Fe³⁺Extraction separation due to the fact that butyl acetate is opposite to Fe in a hydrochloric acid system³⁺Has strong selectivity of only Fe³⁺And extracting the heavy metal elements, and not extracting the other heavy metal elements, so that a large amount of iron matrix is separated without influencing the test of the other heavy metals. And (3) removing the iron matrix from the sample, testing the sample on a machine, matching the sample peak shape chart with the standard liquid peak shape chart, and eliminating spectral interference. Proved by verification, the method has higher accuracy and precision, and can simultaneously detect As, Pb, Cd, Zn, Cr, Co, V and the like in the ferric trichlorideA plurality of trace elements.

In conclusion, the invention has the following beneficial effects:

1. the method has the advantages that the iron matrix is extracted and separated, the spectral interference caused by the iron matrix is effectively eliminated, the detection limit of the method is reduced, the method for simultaneously measuring various trace elements in the ferric trichloride by using the inductively coupled plasma emission spectrometer is created, the detection time is shortened, and the working efficiency is improved.

2. According to the invention, by controlling the working parameters of the key instrument, the linear correlation coefficients corresponding to the element standard curves are respectively as follows: as: 0.999936, Pb: 0.999962, Cd: 0.999994, Zn: 0.999996, Cr: 0.999989, Co: 0.999995, V: 0.999958, the linear correlation coefficient is above 0.9999, which can ensure the precision and accuracy of detection, and can be used for the analysis of standard samples and production samples.

3. The reagent used in the experimental process is relatively safe, and a chemical reagent with high hazard is not used, so that the experimental safety is improved, the environmental pollution is not caused, and the method is relatively environment-friendly.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to specific embodiments.