阅读说明：本技术 一种测定工作场所中草酸含量的方法 (Method for measuring oxalic acid content in workplace ) 是由 林新艳 俞晓明 顾承伟 胡志伟 于 2019-12-19 设计创作，主要内容包括：本发明公开了一种测定工作场所中草酸含量的方法,包括：以碳酸钠和碳酸氢钠混合溶液作为淋洗液,以去离子水作为吸收液,采用Dionex IonPac <Sup>TM</Sup> AS22阴离子分析柱和电导检测器对草酸含量进行离子色谱法测定。(The invention discloses a method for measuring oxalic acid content in a workplace, which comprises the following steps: using a mixed solution of sodium carbonate and sodium bicarbonate as an eluent, using deionized water as an absorption liquid, and adopting Dionex IonPac TM The AS22 anion analytical column and the conductivity detector were used for measuring the oxalic acid content by ion chromatography.)

1. A method for measuring oxalic acid content in a workplace is characterized in that a mixed solution of sodium carbonate and sodium bicarbonate is used as a leacheate, deionized water is used as an absorption liquid, and Dionex IonPac is adopted^TMThe AS22 anion analytical column and the conductivity detector were used for measuring the oxalic acid content by ion chromatography.

2. The method of claim 1, comprising the steps of: drawing a standard curve, collecting a sample, measuring the sample and calculating the concentration of oxalic acid.

3. The method of claim 2, wherein the sample collector is a multi-well glass plate absorber tube containing 5.0mL of deionized water.

4. The method of claim 2, wherein the sample is determined using a Dionex IonPac^TMAnd (3) carrying out ion chromatography determination on the AS22 anion analytical column and a conductivity detector, and carrying out qualitative retention time and quantitative peak area.

The technical field is as follows:

the invention belongs to the technical field of detection of chemical substances in air of workplaces, and particularly relates to a method for determining oxalic acid content in workplaces.

Background art:

oxalic acid, which is named as oxalic acid and one of the simplest organic dibasic acids, plays an important role in industry, can be used for producing cobalt-molybdenum-aluminum catalysts, cleaning metals and marbles and bleaching textiles, and also has wide application in the links of medicine manufacturing, printing and dyeing processing, plastic production and the like. Oxalic acid has certain toxicity, has stimulation and corrosion effects on skin and mucosa, and is easy to be absorbed by epidermis and mucosa to cause poisoning. Oxalic acid is not easy to be oxidized and decomposed in human body, so that the pH value in the human body is out of balance, and the development of children is influenced. The national occupational health standards stipulate that the time-weighted average allowable concentration (PC-TWA) of oxalic acid in the air of a workplace is 1mg/m³The short-time contact tolerance (PC-STEL) was 2mg/m³。

At present, the concentration of oxalic acid is measured by Chinese industrial enterprises according to a method for measuring carboxylic acid compounds in air of workplaces (GBZ/T160.59-2004), the measuring method is a single-column non-inhibition type ion chromatography, and the method has the advantages of complex requirements on column temperature, detector temperature and mobile phase, long testing time and small application range of chromatographic columns.

The invention content is as follows:

the invention aims to overcome the problems in the prior art, and provides a method for measuring the oxalic acid content in a workplace, which is low in cost and high in speed.

In order to achieve the aim, the invention provides a method for measuring the oxalic acid content in a workplace, wherein the method takes a mixed solution of sodium carbonate and sodium bicarbonate as an eluent, takes deionized water as an absorption liquid, and adopts Dionex IonPac^TMThe AS22 anion analytical column and the conductivity detector were used for measuring the oxalic acid content by ion chromatography.

The method provided by the invention comprises the following steps: drawing a standard curve, collecting a sample, measuring the sample and calculating the concentration of oxalic acid.

The drawing of the standard curve comprises the following steps: (1) preparing standard secondary mother liquor: taking 0.5mL of the oxalate standard solution into a 10mL volumetric flask, adding ultrapure water to a constant volume, and uniformly mixing. This is 50 mug/mL of oxalate standard secondary mother liquor. (2) Preparing a standard curve solution: 0.1mL, 0.5mL, 1.0mL, 2.0mL of oxalic acid standard secondary mother liquor were transferred to 10mL, 25mL, 10mL volumetric flasks, respectively, to prepare standard curve solutions of 0.5. mu.g/mL, 1.0. mu.g/mL, 2.0. mu.g/mL, 5.0. mu.g/mL, 10. mu.g/mL. Mixing and performing on-machine analysis. (3) Drawing a standard curve: adjusting an ion chromatograph to an optimal determination state according to the operation conditions of the instrument, feeding 50 muL samples, determining a standard series respectively, repeating the determination for 3 times for each concentration, and drawing a standard curve according to the peak height or peak area average value to the corresponding oxalic acid concentration (mg/mL).

The collecting of the sample comprises: at the sampling point, an air sample of 15min or more was collected at a flow rate of 500mL/min using a fritted glass absorber tube containing 5.0mL of water. After sampling, the air inlet and outlet of the absorption tube are immediately closed, and the absorption tube is transported and stored in a clean container. The sample should be measured as soon as possible.

The determination of the sample comprises: the inner wall of the air inlet pipe is washed for 3 times by using the sample solution in the absorption pipe, and the sample solution is filtered into a test tube with a plug scale for determination. The sample solution and the sample blank solution are measured by using the operating conditions of the measurement standard series, and the measured peak area value is used for obtaining the concentration (mu g/mL) of oxalic acid in the sample solution by a standard curve or a regression equation. If the concentration of oxalic acid in the sample solution exceeds the measuring range, the concentration is measured after being diluted by water, and the dilution times are multiplied when the concentration is calculated.

The calculation of the oxalic acid concentration comprises: the calculation formula of the concentration of oxalic acid in the sample is as follows:

concentration of oxalic acid in milligrams per cubic meter (mg/m) in the workplace³)

C₀Reading by the instrument the concentration of oxalic acid in the sample solution in micrograms per milliliter (. mu.g/mL)

V-volume of sample solution in milliliters (mL)

V₀Standard sample volume in liters (L)

F is the dilution multiple.

Description of the drawings:

FIG. 1 is a test chart of oxalic acid concentration.

The specific implementation mode is as follows:

the following describes in detail specific embodiments of the present invention. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.