Detection of banned dyes in printing and dyeing wastewater using liquid chromatography-tandem mass spectrometry

Abstract

The invention discloses a liquid chromatography-tandem mass spectrometry detection method for banned dyes in printing and dyeing wastewater, comprising the steps of: taking printing and dyeing wastewater sample, adjusting its pH value to neutrality; taking the sample to be tested having adjusted pH and using gravity to pass through solid phase extraction purification column, eluting with methanol, ammonia-methanol solution and formic acid-methanol solution successively after vacuum extraction; eluent is placed in a water bath and nitrogen is blown to dryness and then redissolved with methanol, crosses a hydrophilic PTFE filter membrane; taking the printing and dyeing wastewater sample not containing banned dyes, adjusting its pH value to neutrality, and purifying through the same steps above, obtaining a blank matrix liquid and preparing a matrix standard working solution, sample introduction on a liquid chromatography-tandem mass spectrometer, drawing a working curve; sample introduction on a liquid chromatography-tandem mass spectrometer, using working curve calculation to obtain the concentration of various dyes in printing and dyeing wastewater sample. The present invention can detect the residual toxic and harmful substances such as dyes in printing and dyeing wastewater, provides relevant technical support for printing and dyeing enterprises, and is of great significance to pollution source monitoring and environmental protection.

Description

Technical Field

[0001] The invention relates to chemical detection, in particular to a liquid chromatography-tandem mass spectrometry detection method for banned dyes in printing and dyeing wastewater. Background Art

[0002] Dyes are essential in many key industries, including leather, papermaking, and textiles. GB 4287-2012, "Discharge Standard of Water Pollutants from Textile Dyeing and Finishing Industries," primarily specifies conventional indicators such as pH, chromaticity, ammonia nitrogen, chemical oxygen demand, and biochemical oxygen demand. It does not specify emission values for hazardous substances such as banned carcinogenic and allergenic disperse dyes.

[0003] 2023 Edition of Eco-Textile Standard Standard 100 specifies 22 allergenic dyes, 19 dyes proven to be carcinogenic and prohibited for use in textiles, and four other prohibited dyes. These prohibited dyes can be categorized according to their structural formulas as disperse dyes, direct dyes, acid dyes, basic dyes, and neutral dyes. Currently, there are a number of carcinogenic and allergenic dyes that have been shown to induce cancer in humans or cause allergies to the skin, mucous membranes, or respiratory tract.

[0004] Conventional environmental monitoring indicators are insufficient to fully reflect the compliance of printing and dyeing wastewater pollutants with standards. Therefore, research on a series of detection methods for residual dyes and other toxic and hazardous substances in printing and dyeing wastewater not only provides relevant technical support for printing and dyeing companies but also has important implications for pollution source monitoring and environmental protection. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a liquid chromatography-tandem mass spectrometry detection method for banned dyes in printing and dyeing wastewater, which can detect the residues of toxic and harmful substances such as dyes in printing and dyeing wastewater, provide relevant technical support for printing and dyeing enterprises, and is also of great significance for pollution source monitoring and environmental protection.

[0006] To achieve the above object, the present invention provides the following technical solution: a liquid chromatography-tandem mass spectrometry method for detecting banned dyes in printing and dyeing wastewater, comprising the following steps:

[0007] Prepare the sample to be tested, take a printing and dyeing wastewater sample, and adjust its pH value to neutral;

[0008] Purify the sample to be tested. Pass the pH-adjusted sample through a solid phase extraction cleanup column by gravity. Then, rinse the column with water, discard the effluent, and elute with methanol, ammonia-methanol solution, and formic acid-methanol solution in sequence after vacuum drying. Collect all the eluates in a graduated centrifuge tube. Place the eluate in a water bath, blow nitrogen to dryness, and then reconstitute it with methanol. Pass it through a hydrophilic PTFE filter membrane and then provide it for liquid chromatography-tandem mass spectrometry (LC-MS-MS) analysis.

[0009] Prepare the matrix standard working solution. Take a printing and dyeing wastewater sample that does not contain banned dyes, adjust its pH to neutral, and purify it through the same steps as the above-mentioned purification of the sample to be tested. Take the obtained blank matrix solution to prepare the matrix standard working solution.

[0010] To detect the sample to be tested, the sample solution to be tested and the matrix standard working solution are respectively injected into the liquid chromatography-tandem mass spectrometer, and a working curve is drawn with the concentration of the dye in the matrix standard solution as the horizontal axis and the peak area of each dye quantitative ion pair as the vertical axis. The working curve is then used to calculate the concentration of various dyes in the sample solution to be tested.

[0011] As a further improvement of the present invention, the solid phase extraction purification column is a column used in series, and the fillers are respectively a polymer with styrene-divinylbenzene as a matrix and bonded with N-pyrrolidone hydrophilic groups and a polymer bonded with weak anion exchange groups.

[0012] As a further improvement of the present invention, the solid phase extraction purification column is activated sequentially with methanol and water before use.

[0013] As a further improvement of the present invention, during the preparation of the sample to be tested, the pH value of the printing and dyeing wastewater sample is adjusted to 7.0±0.1 with formic acid or ammonia water.

[0014] As a further improvement of the present invention, the detection method is applied to the detection of Direct Blue 218, Direct Blue 15, Direct Blue 6, Direct Brown 95, Direct Red 28, Direct Black 38, Navy Blue, Solvent Blue 4, and Basic Blue 26 in printing and dyeing wastewater samples.

[0015] As a further improvement of the present invention, the liquid chromatography-tandem mass spectrometry detection conditions were as follows: injection volume 2 μL; chromatographic column: ACQUITY UPLC HSS T3 (100 mm × 2.1 mm, 1.8 μm); column temperature 40°C. The mobile phase was methanol-water; the flow rate was 300 L / min; the gradient elution program was as follows: 0-3.0 min, water 80% → 10%, methanol 20% → 90%; 3.0-7.0 min, maintaining water 10%, methanol 90%; 7.01-9.0 min, returning to water 80%, methanol 20%.

[0016] As a further improvement of the present invention, in the liquid chromatography-tandem mass spectrometer detection, the mass spectrometry conditions are set as follows: ion source temperature: 300°C; heating block temperature: 400°C; desolvation temperature: 250°C; nebulizing gas: nitrogen, 3 L / min; drying gas: nitrogen, 10 L / min; heating gas: air, 10 L / min; scanning mode: multiple reaction monitoring, electrospray ionization (ESI) positive and negative ion simultaneous scanning mode; and the MRM conditions are as follows:

[0017]

[0018] Among them, * marks the quantitative ion pair.

[0019] The beneficial effects of the present invention are that the present scheme can be used to detect Direct Blue 218, Direct Blue 15, Direct Blue 6, Direct Brown 95, Direct Red 28, Direct Black 38, Navy Blue, Solvent Blue 4, and Basic Blue 26 in printing and dyeing wastewater samples, which not only provides relevant technical support for printing and dyeing enterprises, but also has important significance for pollution source monitoring and environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 1 is the MRM spectrum of 9 dyes of the present invention. DETAILED DESCRIPTION

[0021] The present invention will be further described below with reference to the embodiments shown in the accompanying drawings.

[0022] Reference Figure 1 As shown,

[0023] (1) Preparation of samples to be tested:

[0024] Take about 50 mL of printing and dyeing wastewater sample in a 100 mL small beaker, measure its pH value, and adjust its pH value to 7.0±0.1 with formic acid or ammonia water;

[0025] (2) Purification of samples to be tested:

[0026] An HLB cartridge (a polymer material based on styryl-divinylbenzene and bonded with N-pyrrolidone hydrophilic groups) and a WAX cartridge (a polymer material with weak anion exchange groups) were connected in series using connectors and placed in a solid-phase extraction device. The cartridges were activated sequentially with 6 mL of methanol and then 6 mL of water, and then used. A 10 mL water sample was applied to the activated serial cartridges and allowed to pass through them by gravity. The cartridges were then rinsed with 6 mL of water, the effluent discarded, and vacuum-dried for 2 minutes. The cartridges were eluted sequentially with 6 mL of formic acid-methanol (5 + 95%), 6 mL of methanol, and 6 mL of ammonia-methanol (5 + 95%). All eluents were collected in a 50 mL centrifuge tube and dried in a nitrogen purifier at 45°C. The cartridges were reconstituted with 0.5 mL of methanol and filtered through a 0.22 μm hydrophilic PTFE filter before LC-MS-MS analysis.

[0027] (III) Preparation of matrix standard working solution:

[0028] Take a negative wastewater sample without dye and process it according to steps (1) and (2) to obtain a blank sample matrix. Use the blank sample matrix to dilute it step by step to produce a matrix standard working solution of 10, 20, 50, 100, 200, and 500 μg / L.

[0029] (IV) Optimization of MRM conditions for 9 dyes:

[0030] Each single-label standard solution is taken and pushed into the mass spectrometer through the liquid phase system and connected to the two-way. A full scan of the primary mass spectrometer is performed to determine the parent ion, and then a full scan of the product ion is used to obtain the secondary mass spectrum. The quantitative ion and the qualitative ion are selected, and the mass spectrometry parameters such as collision energy are optimized to finally determine the quantitative ion pair and the qualitative ion pair.

[0031] (V) Testing of samples to be tested:

[0032] The water sample to be tested in step (ii) and the matrix standard working solution in step (iii) were injected separately on a liquid chromatography-tandem mass spectrometer, and a working curve was drawn with the concentration of the dye in the standard solution as the horizontal coordinate and the peak area as the vertical coordinate. The concentration of the dye in the water sample to be tested was calculated using the working curve. The results showed that the 9 dyes had a good linear relationship in the range of 10-500 μg / L, with R2 ≥ 0.999. When 1.0 μg / L was added to the negative water sample, the signal-to-noise ratio (S / N) of each dye response on the mass spectrometer was greater than 10, so the quantitative limit of 9 dyes in printing and dyeing wastewater determined by this method was 1.0 μg / L.

[0033] (VI) Liquid chromatography-tandem mass spectrometry detection conditions:

[0034] LC conditions: injection volume 2 μL; chromatographic column: ACQUITY UPLC HSS T3 (100 mm × 2.1 mm, 1.8 m); column temperature 40°C. Mobile phase: methanol-water; flow rate 300 L / min; gradient elution program: 0-3.0 min, water 80% → 10%, methanol 20% → 90%; 3.0-7.0 min, maintain water 10%, methanol 90%; 7.01-9.0 min, return to water 80%, methanol 20%.

[0035] Mass spectrometry conditions: ion source temperature: 300°C; heating block temperature: 400°C; desolvation temperature: 250°C; nebulizing gas: nitrogen, 3 L / min; drying gas: nitrogen, 10 L / min; heating gas: air, 10 L / min; scanning mode: multiple reaction monitoring, electrospray ionization (ESI) positive and negative ion simultaneous scanning mode. The MRM conditions such as ion pairs and voltages for the nine dyes are shown in the table below.

[0036] MRM conditions for 9 dyes

[0037]

[0038]

[0039] Among them, * marks the quantitative ion pair.

[0040] Recovery and precision of 9 dye additions (n=6)

[0041]

[0042] Based on this embodiment, first, the present invention adjusts the pH value of the water sample to neutral by adding formic acid or ammonia water, so that the residual dye in the water sample can be better adsorbed when passing through the column.

[0043] Secondly, the present invention uses a small column made of a polymer material with styrene-divinylbenzene as the matrix and bonded with N-pyrrolidone hydrophilic groups and a small column made of a polymer material with bonded weak anion exchange groups in combination, which can ensure a good recovery rate of 9 banned dyes while ensuring the purification effect.

[0044] Again, the qualitative and quantitative detection of nine banned dyes in printing and dyeing wastewater in the present invention is carried out through liquid chromatography-tandem quadrupole mass spectrometry analysis, and the detection sensitivity is optimized by optimizing the mass spectrometry and chromatographic conditions.

[0045] Nine species were determined using T3 column separation and methanol-water as mobile phase in multiple reaction monitoring mode under positive and negative simultaneous scanning ion mode. Retention time and ion pair ratio were used for qualitative confirmation, and matrix standard solution external standard method was used for quantification.

[0046] It also has the characteristics of simple and rapid sample pretreatment, good purification effect, high sensitivity, and can simultaneously perform quantitative and qualitative confirmation of 9 dyes.

[0047] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiment. All technical solutions based on the concept of the present invention are within the scope of protection of the present invention. It should be noted that for those skilled in the art, various improvements and modifications that do not depart from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A liquid chromatography-tandem mass spectrometry method for detecting banned dyes in printing and dyeing wastewater, characterized in that: The steps include: Prepare the sample to be tested, take a printing and dyeing wastewater sample, and adjust its pH value to neutral; Purify the sample to be tested. Take the sample to be tested after adjusting the pH and pass it through the solid phase extraction cleanup column by gravity. Then, rinse the column with water, discard the effluent, vacuum dry it, and elute it with formic acid-methanol solution, methanol, and ammonia-methanol solution in sequence. Collect all the eluents in a graduated centrifuge tube; place the eluent in a water bath and blow it with nitrogen to dryness, then reconstitute it with methanol, pass it through a hydrophilic PTFE filter membrane, and then provide it for liquid chromatography-tandem mass spectrometry analysis. Prepare the matrix standard working solution by taking a printing and dyeing wastewater sample that does not contain banned dyes, adjusting its pH to neutral, and purifying it through the same steps as the sample to be tested; Detecting the sample to be tested, the sample solution to be tested and the matrix standard working solution are respectively injected on a liquid chromatography-tandem mass spectrometer, and a working curve is drawn with the concentration of the dye in the matrix standard solution as the horizontal axis and the peak area of each dye quantitative ion pair as the vertical axis, and then the working curve is used to calculate the concentration of each dye in the sample solution to be tested; The solid phase extraction purification column is a column used in series, and the fillers are a polymer with a styrene-divinylbenzene matrix and bonded with an N-pyrrolidone hydrophilic group and a polymer bonded with a weak anion exchange group; This detection method is applied to the detection of direct blue 218, direct blue 15, direct blue 6, direct brown 95, direct red 28, direct black 38, navy blue, solvent blue 4 and basic blue 26 in printing and dyeing wastewater samples.

2. The liquid chromatography-tandem mass spectrometry method for detecting banned dyes in printing and dyeing wastewater according to claim 1, characterized in that: The solid phase extraction purification column is activated sequentially with methanol and water before use.

3. The liquid chromatography-tandem mass spectrometry method for detecting banned dyes in printing and dyeing wastewater according to claim 1, characterized in that: During the preparation of the sample to be tested, the pH value of the printing and dyeing wastewater sample was adjusted to 7.0±0.1 with formic acid or ammonia water.

4. The method for detecting banned dyes in printing and dyeing wastewater by liquid chromatography-tandem mass spectrometry according to claim 1, characterized in that: In liquid chromatography-tandem mass spectrometry detection, the liquid phase conditions were set as follows: injection volume 2 μL; chromatographic column: ACQUITY UPLC HSS T3, column temperature 40°C; mobile phase: methanol-water; flow rate 300 L / min, gradient elution program as follows: 0-3.0 min, water 80%→10%, methanol 20%→90%; 3.0-7.0 min, maintain water 10%, methanol 90%; 7.01-9.0 min, return to water 80%, methanol 20%.

5. The liquid chromatography-tandem mass spectrometry method for detecting banned dyes in printing and dyeing wastewater according to claim 4, characterized in that: In the liquid chromatography-tandem mass spectrometry detection, the mass spectrometry conditions were set as follows: ion source temperature: 300°C; heating block temperature: 400°C; desolvation temperature: 250°C; nebulizing gas: nitrogen, 3 L / min; drying gas: nitrogen, 10 L / min; heating gas: air, 10 L / min; scanning mode: multiple reaction monitoring, electrospray ionization (ESI) positive and negative ion simultaneous scanning mode; and the MRM conditions were as follows: Among them, * marks the quantitative ion pair.

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