Quantitative detection method for low-concentration urea in ultrapure water

A quantitative detection method and low-concentration technology, applied in the field of quantitative detection of low-concentration urea, can solve problems such as failure to meet urea detection requirements, and achieve the effect of increasing stability

Pending Publication Date: 2022-05-27
CHINA ELECTRONICS INNOVATION ENVIRONMENTAL TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The national standard method (GB / T18204.2-2014) uses the diacetylmonoxime-antipyrine spectrophotometer method to detect urea, but this method cannot accurately detect the concentration of 5ug / Urea below L is obviously unable to meet the urea testing requirements for recycled water in the electronics industry

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  • Quantitative detection method for low-concentration urea in ultrapure water
  • Quantitative detection method for low-concentration urea in ultrapure water
  • Quantitative detection method for low-concentration urea in ultrapure water

Examples

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Embodiment 1

[0025] The quantitative detection method of low-concentration urea in ultrapure water of the present invention specifically comprises the following steps:

[0026] Step (1), take 250mL of the initial water sample and put it into a PTFE plastic bottle, tighten the bottle cap, then pre-freeze it in a -80°C freezer for 24 hours, take it out, unscrew the bottle cap, and put the PTFE plastic bottle. The bottle was placed in a vacuum freeze dryer and dried for 24 hours. After drying, the polytetrafluoroethylene plastic bottle was taken out and placed at room temperature until the ice cubes in it were completely dissolved; at this time, water (same as the initial water sample) was added to the liquid by constant volume. water with the same composition), until the liquid volume is 1 / 10 of the initial water sample volume (ie 25mL); the vacuum degree of the dryer is 0.05MPa, and the temperature is -50℃; the urea concentration in the initial water sample is 0.3ug / L; the vacuum After free...

Embodiment 2

[0071] The quantitative detection method of low-concentration urea in ultrapure water of the present invention specifically comprises the following steps:

[0072] Step (1), take 250mL of the initial water sample and put it into a PTFE plastic bottle, tighten the bottle cap, then pre-freeze it in a -80°C freezer for 24 hours, take it out, unscrew the bottle cap, and put the PTFE plastic The bottle was placed in a vacuum freeze dryer and dried for 24 hours. After drying, the polytetrafluoroethylene plastic bottle was taken out and placed at room temperature until the ice cubes in it were completely dissolved; at this time, water (same as the initial water sample) was added to the liquid by constant volume. water with the same composition), until the liquid volume is 1 / 10 of the initial water sample volume (ie 25mL); the vacuum degree of the dryer is 0.05MPa, and the temperature is -50℃; the urea concentration in the initial water sample is 0.4ug / L; the vacuum After freeze-dryin...

Embodiment 3

[0080] The quantitative detection method of low-concentration urea in ultrapure water of the present invention specifically comprises the following steps:

[0081] Step (1), take 250mL of the initial water sample and put it into a PTFE plastic bottle, tighten the bottle cap, then pre-freeze it in a -80°C freezer for 24 hours, take it out, unscrew the bottle cap, and put the PTFE plastic The bottle was placed in a vacuum freeze dryer and dried for 24 hours. After drying, the polytetrafluoroethylene plastic bottle was taken out and placed at room temperature until the ice cubes in it were completely dissolved; at this time, water (same as the initial water sample) was added to the liquid by constant volume. water with the same composition), until the liquid volume is 1 / 10 of the initial water sample volume (ie 25mL); the vacuum degree of the dryer is 0.05MPa, and the temperature is -50℃; the urea concentration in the initial water sample is 0.5ug / L; the vacuum After freeze-dryin...

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Abstract

The invention discloses a quantitative detection method for low-concentration urea in ultrapure water. The quantitative detection method specifically comprises the following steps: firstly, carrying out vacuum freeze drying treatment on a water sample; putting the water sample subjected to vacuum freeze drying into a reaction container, sequentially adding a diacetylmonoxime solution, a stabilizer and a catalyst into a tube, and putting the reaction container at high temperature for reaction under the condition that a tube opening is closed; and putting the reacted reaction liquid into a measuring container, measuring the absorbance of the reaction liquid by using a spectrophotometer, and obtaining the concentration of urea in the initial water sample according to the standard curve. According to the quantitative detection method, the urea with the concentration of 0.5-80 [mu] g / L in the water body can be accurately detected; according to the method, a water sample containing low-concentration urea is firstly subjected to vacuum freeze drying treatment, and then the concentration of diacetyl monooxime and antipyrine / thiourea is increased to increase the color of a solution after reaction, so that the detection lower limit value of the concentration of urea in a water body is effectively reduced; meanwhile, according to the method, metal ions are added to accelerate the reaction and increase the stability of color development, so that the absorbance is almost not reduced compared with the absorbance at 0 after the reaction liquid after the reaction is placed for a period of time.

Description

technical field [0001] The invention relates to a quantitative detection method for low-concentration urea in ultrapure water. Background technique [0002] Urea is considered an important pollutant in the production of ultrapure water (UPW) in the electronics industry. After actual water testing and literature research, it is found that the content of urea in tap water is 10-30ug / L, and the content in reclaimed water is 40-100ug / L. After the tap water is treated by the conventional ultrapure water treatment system, the total organic carbon (TOC) of the terminal effluent is less than 1ug / L, which meets the effluent standard. However, if reclaimed water is used, the terminal effluent is often substandard, and urea has been proven to be one of the main reasons for substandard. Additionally, urea releases ammonium when heated, which can negatively impact the lithography process. Therefore, it is necessary to develop a urea treatment process for reclaimed water, and embed the...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N21/33G01N21/78G01N1/40G01N1/42G01N1/44
CPCG01N21/33G01N21/78G01N1/40G01N1/42G01N1/44Y02A20/20
Inventor 蒋士龙赵浩竹熊江磊操家顺程松蔡宏展袁润博
Owner CHINA ELECTRONICS INNOVATION ENVIRONMENTAL TECH CO LTD
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