A method for determining piperidine in solid waste and leachate

Abstract

The present application belongs to the technical field of piperidine testing, and particularly relates to a method for determining piperidine in solid waste and leaching liquid. After being pretreated, the sample to be detected is loaded into a purge bottle and sealed, and after being purged and collected, the piperidine in the sample to be detected is determined by gas chromatography-mass spectrometry. The method can accurately determine the piperidine in the solid waste and leaching liquid.

Description

Technical Field

[0001] This invention belongs to the field of piperidine testing technology, specifically relating to a method for determining piperidine in solid waste and leachate. Background Technology

[0002] Piperidine is a nitrogen-containing six-membered cyclic organic compound, a colorless liquid at room temperature with a pungent, pepper-like odor. It is widely used in pharmaceutical synthesis and organic chemistry experiments. Piperidine is classified as a Class II controlled toxic chemical and a Class B flammable and corrosive hazardous chemical. It can damage the human respiratory, liver, kidney, and nervous systems. Excessive piperidine emissions in wastewater and exhaust gases generated during production can cause water and soil pollution, harming the ecological environment. Therefore, accurate detection of piperidine content in samples is essential for controlling product manufacturing processes, controlling residual impurities, ensuring product quality and safety, and meeting industry compliance standards and environmental protection emission requirements. This effectively mitigates quality risks, occupational health risks, and environmental pollution risks.

[0003] Bai Yike et al. established a gas chromatography method for the simultaneous determination of piperidine and pyridine in minoxidil raw material. A DB-1 capillary column (60m × 320µm × 1.0µm), a flame ionization detector, nitrogen as the carrier gas, a flow rate of 1.0 mL / min, an injection port temperature of 225℃, a split ratio of 10:1, and a detector temperature of 260℃ were used. The results showed that piperidine and pyridine exhibited good linearity within the ranges of 2.4–47.8 and 2.3–45.4 mg / L, respectively; the limits of detection were 1.20 mg / L and 1.14 mg / L, respectively; and the RSD% in the parallelism test (n=9) were 6.66% and 4.40%, respectively. However, this method lacks advantages in linearity and sensitivity. For solid waste samples with complex matrices, false positives may occur, and the liquid injection method is unsuitable for determining the piperidine content in aqueous matrix extracts.

[0004] Liu Kuikui et al. established a headspace gas chromatography method for the simultaneous determination of piperidine and pyridine in telostatin. An RTX-35 Amine column (35% biphenyl and 65% dimethyl polysiloxane as stationary phase, 30 m × 0.32 mm × 1 µm) and a flame ionization detector were used. The temperature program was as follows: injection temperature 220 °C, detector temperature 250 °C, high-purity nitrogen as carrier gas, flow rate 1.5 mL / min, headspace equilibration temperature 90 °C, and equilibration time 30 min. The resolution between piperidine and pyridine was greater than 2.0, and there was no interference from the blank solvent. Pyridine and piperidine showed good linearity (r ≥ 0.9998) in the concentration ranges of 0.40–40.32 mg / L and 0.41–40.96 mg / L, respectively. The limits of detection were 0.13 mg / L and 0.12 mg / L, and the limits of quantitation were 0.41 mg / L and 0.40 mg / L, respectively. Compared with gas chromatography with liquid injection, this method can determine the piperidine content in aqueous matrix extracts, but the method sensitivity will be significantly worse. It also has the potential for false positives in solid waste samples with complex matrices. Furthermore, DMF is used as a solvent and is prone to remain in the system, interfering with subsequent sample determinations.

[0005] Shang Meirong and Wang Xin established a high-performance liquid chromatography (HPLC) method for determining piperidine content in dipyridamole raw material. The piperidine was dissolved in methanol, derivatized with 2,4-dinitrofluorobenzene, and then diluted to volume with acetonitrile. The chromatographic column was an Agilent C18 (4.6 × 150 mm, 5 μm); the mobile phase was methanol-water (70:30); the flow rate was 1.0 mL / min; the column temperature was 30℃; the detection wavelength was 388 nm; and the injection volume was 10 μL. The method showed good linearity in the concentration range of 39.81 mg / L to 149.3 mg / L, with a detection limit of 0.02% and precision of 3.6%–5.5%. However, the linear range and detection limit of this method do not meet the detection requirements, as they exceed the control limits for piperidine in solid waste, and the derivatization pretreatment is relatively complex.

[0006] Zhong Xinlin established an ion chromatography-suppressive conductivity method for the determination of residual piperidine in peptide drugs. An IonPac CS17 separation column (4×250 mm) was used, with an IonPac CG17 guard column (4 mm×50 mm). The eluent was 7 mmol / L methanesulfonic acid aqueous solution, the flow rate was 1.0 mL / min, the quantitative loop was 125 µL, the column temperature was 30 °C, and a conductivity detector was used. An anion exchange continuously regenerating micromembrane suppressor was employed, with a suppression current of 30 mA, a back pressure of 1800 psi, and a background conductivity of 0.3 µS. The linear range was 0.2–2.0 mg / L, the limit of detection was 0.002 mg / L, and the RSD% (n=7) was 0.71%. Ion chromatography has limited parameters that can be optimized and adjusted, resulting in poor method selectivity. For the detection of solid waste samples, it cannot effectively eliminate interference from complex matrices on the target components.

[0007] Piperidine, being a saturated nitrogen heterocycle, is highly basic, and conventional detection methods suffer from poor peak shape and low sensitivity. Furthermore, the complex matrix of solid waste samples interferes with the quantification of the target component, potentially leading to false positives. Methods for determining piperidine content in aqueous matrix extracts also exhibit low sensitivity. Therefore, it is necessary to establish a simple, efficient, highly sensitive, and highly accurate method for the quantitative detection of piperidine in solid waste and extracts. Summary of the Invention

[0008] The purpose of this invention is to provide a method for determining piperidine in solid waste and leachate.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A purge-trap-gas chromatography / mass spectrometry method for determining piperidine in solid waste and leachate involves pretreating the sample, sealing it in a purge bottle, and then determining the piperidine content in the sample using gas chromatography-mass spectrometry after purge-trap.

[0010] Specifically: 1) Prepare piperidine standard solution and determine it by gas chromatography-mass spectrometry after purge and trapping. Obtain the chromatogram of piperidine standard solution and plot the standard curve of piperidine with peak area as the ordinate and the corresponding concentration of standard solution as the abscissa. 2) After pretreatment, the sample to be tested is placed in a purge bottle and sealed. After purging and collection, it is determined by gas chromatography-mass spectrometry to obtain a chromatogram. The content of piperidine in the sample to be tested is calculated by the external standard method.

[0011] The sample to be tested is either solid waste or extract.

[0012] The pretreatment of the sample to be tested is as follows: sodium hydroxide solution is added to the sample to be tested; the concentration of the sodium hydroxide solution is 0.1 mol / L, and the volume of sodium hydroxide solution added is 4 to 8 times the mass of the sample to be tested.

[0013] The purge and trap conditions were as follows: purge and trap injection, purge temperature: 45℃~50℃, purge time: 11 min, purge flow rate: 40 mL / min, baking time: 2 min, baking temperature: 250℃~270℃, desorption time: 2 min, desorption temperature: 240℃~250℃.

[0014] Preferably, the purge temperature is 45℃, the purge time is 11 min, the purge flow rate is 40 mL / min, the baking time is 2 min, the baking temperature is 260℃, the desorption time is 2 min, and the desorption temperature is 250℃.

[0015] The gas chromatography conditions were as follows: VF-624ms column (30m×0.320mm, 1.8μm), injection method: purge injection, injection port temperature: 250℃~270℃, scan method: Scan, column temperature: initial temperature 50℃~60℃, hold for 2 min, increase to 150℃~170℃ at a rate of 15℃~20℃ / min, hold for 0 min, increase to 250℃~260℃ at a rate of 40℃~50℃ / min, hold for 2 min, column flow rate: 1.5mL / min, split ratio: 50:1.

[0016] Preferably, the chromatographic conditions are as follows: VF-624ms column (30m×0.320mm, 1.8μm), injection method: purge injection, injection port temperature: 270℃, scan method: Scan, column temperature: initial temperature 60℃, hold for 2 min, increase to 150℃ at a rate of 15℃ / min, hold for 0 min, increase to 250℃ at a rate of 50℃ / min, hold for 2 min, column flow rate: 1.5mL / min, split ratio: 50:1.

[0017] The mass spectrometry conditions were as follows: scan range: 40~100 aum, ionization energy: 70 eV, scan mode: SCAN, ion source temperature: 230℃, quadrupole temperature: 150℃, interface temperature: 280℃.

[0018] Advantages of this invention: The method of the present invention can achieve accurate quantification of piperidine in solid waste and leachate.

[0019] Compared with gas chromatography, the method of this invention has both qualitative and quantitative functions, can avoid false positive detection, and effectively avoids the interference of solvent addition and solid waste sample matrix on the quantification of target components and the damage to instruments and chromatographic columns. The method has higher detection sensitivity and accuracy.

[0020] Compared with liquid chromatography, the method of the present invention does not require derivatization of sample pretreatment, is simple and quick to operate, has little loss or impact on the target components in the sample, produces good peak shape, and has high detection sensitivity.

[0021] Compared with ion chromatography, the method of this invention has higher selectivity, can effectively avoid interference of solid waste sample matrix on target components, and has high detection sensitivity.

[0022] This invention establishes a simple, efficient, highly sensitive, and highly accurate method for the quantitative detection of piperidine, which can meet the requirements for determining the piperidine content in solid waste samples and leachates.

[0023] This invention uses purge-trap-gas chromatography-mass spectrometry instead of gas chromatography, prepares samples with NaOH solution, and uses a VF-624ms column. The sample preparation is simple and efficient, without sample matrix interference, and can achieve high sensitivity. Attached Figure Description

[0024] Figure 1 The chromatogram of the piperidine standard solution provided in Example 1 of the present invention is shown.

[0025] Figure 2 This is a chromatogram of a solid waste sample provided in Embodiment 2 of the present invention.

[0026] Figure 3 The chromatogram of the solid waste extract sample provided in Example 3 of the present invention is shown.

[0027] Figure 4 This is a chromatogram of a solid waste sample provided in Comparative Example 1 of the present invention.

[0028] Figure 5 The chromatogram of the piperidine standard solution provided in Comparative Example 2 of this invention is shown.

[0029] Figure 6 This is a chromatogram of a solid waste sample provided in Comparative Example 2 of the present invention.

[0030] Figure 7 The chromatogram of the piperidine standard solution provided in Comparative Example 3 of this invention is shown.

[0031] Figure 8 This is a chromatogram of a solid waste sample provided in Comparative Example 3 of the present invention.

[0032] Figure 9 The chromatogram of the piperidine standard solution provided in Comparative Example 4 of this invention is shown.

[0033] Figure 10 This is a chromatogram of a solid waste sample provided in Comparative Example 4 of the present invention. Detailed Implementation

[0034] The following examples further illustrate specific embodiments of the present invention. It should be noted that the specific embodiments described herein are merely for illustration and explanation and are not intended to limit the scope of the present invention.

[0035] The reagents used in the embodiments of this invention are: piperidine standard material (Sinopharm Chemical Reagent Co., Ltd.); sodium hydroxide (analytical grade).

[0036] The instruments and equipment used in the embodiments of this invention are: electronic balance (METTLER TOLEDO); purge and trap (Atomx XYZ, Electronic Teledyne Corporation, USA); and gas chromatography-mass spectrometry (Agilent 8890+5977B).

[0037] Example 1 Determination of piperidine standard solution: 1. Preparation of standard solutions: Weigh approximately 0.025 g (accurate to 0.00001 g) of piperidine standard into a 25 mL volumetric flask, and dilute to the mark with 0.1 mol / L NaOH solution to obtain a piperidine standard solution with a theoretical concentration of 1000 mg / L. Take 0.025 mL, 0.125 mL, 0.250 mL, 0.500 mL, 1.00 mL, 1.50 mL, 2.00 mL, and 2.50 mL of piperidine standard solution with a concentration of 1000 mg / L into 25 mL volumetric flasks, respectively, and dilute to the mark with 0.1 mol / L NaOH solution to obtain piperidine standard solutions with theoretical concentrations of 1.00 mg / L, 5.00 mg / L, 10.0 mg / L, 20.0 mg / L, 40.0 mg / L, 60.0 mg / L, 80.0 mg / L, and 100 mg / L. Accurately transfer 20 mL of the above standard solutions into a purge bottle, immediately cap and seal, and prepare for analysis.

[0038] 2. Determination of standard solutions using purge-trap-gas chromatography-mass spectrometry: Purge and trap sampling, purge temperature: 45℃, purge time: 11min, purge flow rate: 40mL / min, baking time: 2min, baking temperature: 260℃, desorption time: 2min, desorption temperature: 250℃.

[0039] Chromatographic conditions: Column: VF-624ms column (30m×0.320mm, 1.8μm), injection method: purge injection, injection port temperature: 270℃, scan method: Scan, column temperature: initial temperature 60℃, hold for 2 min, increase to 150℃ at a rate of 15℃ / min, hold for 0 min, increase to 250℃ at a rate of 50℃ / min, hold for 2 min, column flow rate: 1.5mL / min, split ratio: 50:1.

[0040] Mass spectrometry conditions: Scan range: 40~100 aum, ionization energy: 70 eV, scan mode: SCAN, ion source temperature: 230℃, quadrupole temperature: 150℃, interface temperature: 280℃.

[0041] The piperidine standard solutions of different concentrations were collected by purge and trap and then analyzed by gas chromatography-mass spectrometry (GC-MS). Chromatograms of the piperidine standard solutions were obtained. The chromatogram of the 100 mg / L piperidine standard solution is shown below. Figure 1 A standard curve for piperidine was plotted with peak area as the ordinate and the concentration of the corresponding standard solution (see Table 1) as the abscissa: Y = 27406.9023X - 0.9743, R = 0.99916.

[0042] Table 1

[0043] Example 2 Determination of piperidine in waste sodium chloride salt: 1. Sample preparation: A sample of sodium chloride salt (sodium chloride content > 95%), a by-product of the production process of a pesticide company in Shandong Province, was selected. About 5g of waste salt sample was weighed into a purge bottle, 20mL of 0.1mol / L sodium hydroxide solution was added, and the bottle was immediately capped and sealed for testing.

[0044] 2. Determination of piperidine in waste salt using purge-trap-gas chromatography-mass spectrometry: Purge and trap sampling, purge temperature: 45℃, purge time: 11min, purge flow rate: 40mL / min, baking time: 2min, baking temperature: 260℃, desorption time: 2min, desorption temperature: 250℃.

[0045] Chromatographic conditions: Column: VF-624ms column (30m×0.320mm, 1.8μm), injection method: purge injection, injection port temperature: 270℃, scan method: Scan, column temperature: initial temperature 60℃, hold for 2 min, increase to 150℃ at a rate of 15℃ / min, hold for 0 min, increase to 250℃ at a rate of 50℃ / min, hold for 2 min, column flow rate: 1.5mL / min, split ratio: 50:1.

[0046] Mass spectrometry conditions: Scan range: 40~100 aum, ionization energy: 70 eV, scan mode: SCAN, ion source temperature: 230℃, quadrupole temperature: 150℃, interface temperature: 280℃.

[0047] The prepared samples were analyzed by purge-trap-gas chromatography-mass spectrometry to obtain the chromatogram of piperidine in the waste salt samples, as shown in the figure. Figure 2 Based on retention time and corresponding peak area, the piperidine content in the sample was quantitatively determined by referring to a standard curve. The test results showed that, with a running time of 12 minutes, the mass percentage of piperidine in the sodium chloride waste salt sample was 3.37 × 10⁻⁶. -3 %.

[0048] Example 3 Determination of piperidine in extract: 1. Sample preparation: Select the waste salt sample from Example 2, weigh the sample into an extraction bottle, add ultrapure water according to the sample water content at a liquid-to-solid ratio of 10:1 (L / kg), adjust the rotation speed to (30±2) r / min, and invert and extract at 23±2℃ for 18±2h. Take 20ml of the extract into a purge bottle, add a small amount of 10mol / L sodium hydroxide solution, adjust the pH to >13, and immediately cap and seal for testing.

[0049] 2. Determination of piperidine in waste salt using purge-trap-gas chromatography-mass spectrometry: Purge and trap sampling, purge temperature: 45℃, purge time: 11min, purge flow rate: 40mL / min, baking time: 2min, baking temperature: 260℃, desorption time: 2min, desorption temperature: 250℃.

[0050] Chromatographic conditions: Column: VF-624ms column (30m×0.320mm, 1.8μm), injection method: purge injection, injection port temperature: 270℃, scan method: Scan, column temperature: initial temperature 60℃, hold for 2 min, increase to 150℃ at a rate of 15℃ / min, hold for 0 min, increase to 250℃ at a rate of 50℃ / min, hold for 2 min, column flow rate: 1.5mL / min, split ratio: 50:1.

[0051] Mass spectrometry conditions: Scan range: 40~100 aum, ionization energy: 70 eV, scan mode: SCAN, ion source temperature: 230℃, quadrupole temperature: 150℃, interface temperature: 280℃.

[0052] The prepared samples were analyzed by purge-trap-gas chromatography-mass spectrometry to obtain the chromatogram of piperidine in the waste salt extract sample, as shown in the figure. Figure 3 Based on the retention time and corresponding peak area, the content of piperidine in the sample was quantitatively obtained by referring to the standard curve. The test results showed that the concentration of piperidine in the sodium chloride waste salt leachate sample was 13.943 mg / L after a running time of 12 min.

[0053] Comparative Example 1 The pretreatment conditions for sample preparation are different from those in Example 2; 1. Sample preparation: Weigh about 5g of the waste salt sample from Example 2 into a purge bottle, add 5mL of 0.1mol / L sodium hydroxide solution, immediately cap and seal, and wait for testing.

[0054] 2. Determination of piperidine in waste salt by purge-trap-gas chromatography-mass spectrometry: Purge and trap sampling, purge temperature: 40℃, purge time: 11min, purge flow rate: 40mL / min, baking time: 2min, baking temperature: 260℃, desorption time: 2min, desorption temperature: 250℃.

[0055] Chromatographic conditions: Column: VF-624ms column (30m×0.320mm, 1.8μm), injection method: purge injection, injection port temperature: 200℃, scan method: Scan, column temperature: initial temperature 40℃, hold for 2 min, increase to 140℃ at a rate of 6℃ / min, hold for 0 min, increase to 200℃ at a rate of 50℃ / min, hold for 2 min, column flow rate: 1.5mL / min, split ratio: 10:1.

[0056] Mass spectrometry conditions: scan range 35~400 aum, ionization energy 70 eV, scan mode: SCAN, ion source temperature: 230℃, quadrupole temperature: 150℃, interface temperature: 280℃.

[0057] The prepared samples were analyzed by purge-trap-gas chromatography-mass spectrometry to obtain the chromatogram of piperidine in the waste salt samples, as shown in the figure. Figure 4 ,Depend on Figure 4 It is evident that when a small amount of sodium hydroxide solution is added during sample processing, the piperidine response value is low under these conditions. Therefore, after changing the sample preparation, temperature program, and purging conditions, accurate detection of piperidine cannot be achieved.

[0058] Comparative Example 2 I. Determination of piperidine standard solution: 1. Preparation of standard solutions: Weigh approximately 0.025 g (accurate to 0.00001 g) of piperidine standard into a 25 mL volumetric flask and dilute to the mark with ultrapure water to obtain a piperidine standard solution with a theoretical concentration of 1000 mg / L. Transfer 0.25 mL of the 1000 mg / L piperidine standard solution into a 25 mL volumetric flask and dilute to the mark with ultrapure water to obtain a piperidine standard solution with a theoretical concentration of 10.0 mg / L. Accurately transfer 20 mL of the above standard solution into a purge bottle, immediately cap and seal, and prepare for analysis.

[0059] 2. Determination of standard solutions using purge-trap-gas chromatography-mass spectrometry: Chromatographic conditions: Column: VF-624ms column (30m×0.320mm, 1.8μm), injection method: purge injection, injection port temperature: 200℃, scan method: Scan, column temperature: initial temperature 40℃, hold for 2 min, increase to 140℃ at a rate of 6℃ / min, hold for 0 min, increase to 200℃ at a rate of 50℃ / min, hold for 2 min, column flow rate: 1.5mL / min, split ratio: 10:1.

[0060] Mass spectrometry conditions: scan range 35~400 aum, ionization energy 70 eV, scan mode: SCAN, ion source temperature: 230℃, quadrupole temperature: 150℃, interface temperature: 280℃.

[0061] The chromatogram of the piperidine standard solution is shown in the figure. Figure 5 .

[0062] II. Determination of piperidine in sodium chloride waste salt: The pretreatment conditions for sample preparation differ from those in Example 2, specifically: 1. Sample preparation: Weigh about 5g of the waste salt sample from Example 2 into a purge bottle, add 20mL of ultrapure water, immediately cap and seal, and wait for testing.

[0063] 2. Determination of piperidine in waste salt using purge-trap-gas chromatography-mass spectrometry: Chromatographic conditions: Column: VF-624ms column (30m×0.320mm, 1.8μm), injection method: purge injection, injection port temperature: 200℃, scan method: Scan, column temperature: initial temperature 40℃, hold for 2 min, increase to 140℃ at a rate of 6℃ / min, hold for 0 min, increase to 200℃ at a rate of 50℃ / min, hold for 2 min, column flow rate: 1.5mL / min, split ratio: 10:1.

[0064] Mass spectrometry conditions: scan range 35~400 aum, ionization energy 70 eV, scan mode: SCAN, ion source temperature: 230℃, quadrupole temperature: 150℃, interface temperature: 280℃.

[0065] The chromatogram of piperidine in the waste salt sample was obtained, see... Figure 6 .

[0066] Depend on Figure 5 and Figure 6 It is evident that if the sample is not pretreated with sodium hydroxide solution, the piperidine response value is low, the peak shape is tailed, the sensitivity is low, and accurate detection of piperidine cannot be achieved.

[0067] Comparative Example 3 I. Determination of piperidine standard solution: 1. Take the 20 mg / L piperidine standard solution prepared in Example 1.

[0068] 2. Determination of piperidine standard solution using headspace gas chromatography-mass spectrometry: Sample introduction method: headspace injection; heating equilibrium temperature: 80℃; heating equilibrium time: 30min; sampling needle temperature: 100℃; transfer line temperature: 110℃. The chromatographic conditions were as follows: column: VF-624ms column (30m×0.320mm, 1.8μm), injection port temperature: 250℃, scan mode: Scan, column temperature: initial temperature 40℃, hold for 2 min, increase to 140℃ at a rate of 6℃ / min, hold for 0 min, increase to 220℃ at a rate of 10℃ / min, hold for 3 min, column flow rate: 1.5mL / min, split ratio: 10:1.

[0069] Mass spectrometry conditions: Scan range: 30~450 aum, ionization energy: 70 eV, scan mode: SCAN, ion source temperature: 230℃, quadrupole temperature: 150℃, interface temperature: 270℃.

[0070] The chromatogram of the piperidine standard solution is shown in the figure. Figure 7 .

[0071] II. Determination of piperidine in sodium chloride waste salt: The injection method differs from that in Example 2; 1. Sample preparation: Weigh about 5g of the waste salt sample from Example 2 into a headspace vial, add 10mL of 0.1mol / L sodium hydroxide solution, immediately cap and seal, and wait for testing.

[0072] 2. Determination of piperidine in waste salt using headspace gas chromatography-mass spectrometry: Sample introduction method: headspace injection; heating equilibrium temperature: 80℃; heating equilibrium time: 30min; sampling needle temperature: 100℃; transfer line temperature: 110℃. The chromatographic conditions were as follows: column: VF-624ms column (30m×0.320mm, 1.8μm), injection port temperature: 250℃, scan mode: Scan, column temperature: initial temperature 40℃, hold for 2 min, increase to 140℃ at a rate of 6℃ / min, hold for 0 min, increase to 220℃ at a rate of 10℃ / min, hold for 3 min, column flow rate: 1.5mL / min, split ratio: 10:1.

[0073] Mass spectrometry conditions: Scan range: 30~450 aum, ionization energy: 70 eV, scan mode: SCAN, ion source temperature: 230℃, quadrupole temperature: 150℃, interface temperature: 270℃.

[0074] Chromatogram of piperidine in waste salt sample, see Figure 8 .

[0075] Depend on Figure 7 and Figure 8 It is evident that the piperidine peak tails after the injection method is changed, therefore, accurate detection of piperidine cannot be achieved after changing the sample injection conditions.

[0076] Comparative Example 4 I. Determination of piperidine standard solution: 1. Take the 5 mg / L piperidine standard solution prepared in Example 1.

[0077] 2. Determination of piperidine standard solution using headspace gas chromatography-mass spectrometry: Sample introduction method: headspace injection; heating equilibrium temperature: 70℃; heating equilibrium time: 30min; sampling needle temperature: 100℃; transfer line temperature: 110℃. The chromatographic conditions were as follows: column: CP-Volamine column (30m × 0.320mm), injection port temperature: 250℃, detector: FID, detector temperature: 260℃, column temperature: initial temperature 60℃, hold for 1 min, increase to 140℃ at a rate of 10℃ / min, hold for 5 min, increase to 250℃ at a rate of 50℃ / min, hold for 5 min, column flow rate: 1.0 mL / min, split ratio: 5:1.

[0078] The chromatogram of the piperidine standard solution is shown in the figure. Figure 9 .

[0079] II. Determination of piperidine in sodium chloride waste salt: The injection method and measurement method are different from those in Example 2; 1. Sample preparation: Weigh about 5g of the waste salt sample from Example 2 into a headspace vial, add 10mL of 0.1mol / L sodium hydroxide solution, immediately cap and seal, and wait for testing.

[0080] 2. Headspace-gas chromatography determination of piperidine standard solution: Sample introduction method: headspace injection; heating equilibrium temperature: 70℃; heating equilibrium time: 30min; sampling needle temperature: 100℃; transfer line temperature: 110℃. The chromatographic conditions were as follows: column: CP-Volamine column (30m × 0.320mm), injection port temperature: 250℃, detector: FID, detector temperature: 260℃, column temperature: initial temperature 60℃, hold for 1 min, increase to 140℃ at a rate of 10℃ / min, hold for 5 min, increase to 250℃ at a rate of 50℃ / min, hold for 5 min, column flow rate: 1.0 mL / min, split ratio: 5:1.

[0081] Chromatogram of piperidine in waste salt sample, see Figure 10 .

[0082] Depend on Figure 9 and Figure 10 It is evident that after changing the injection method and determination method, the piperidine response value is low, and there are impurity peaks after piperidine that are not completely separated, resulting in interference. Therefore, after changing the sample preparation, detector and chromatographic column type, and injection conditions, accurate detection of piperidine cannot be achieved.

[0083] The precision of the method in the embodiments of the present invention was verified by a precision test, and the RSD result was 5.4% (see Table 2). This demonstrates that the method of the present invention has higher precision and better reproducibility.

[0084] Table 2. Method precision validation

[0085] In summary, the method of this invention can achieve effective quantification of piperidine in samples. The sample is prepared using NaOH solution, and the purge-trap-gas chromatography-mass spectrometry (PCMS) method is used with specific chromatographic conditions (VF-624ms column). The sample preparation is simple and efficient, without sample matrix interference, and can achieve high sensitivity.

Claims

1. A method for determining piperidine in solid waste and leachate, characterized in that: After pretreatment, the sample to be tested was placed in a purge bottle and sealed. After purge and collection, the piperidine in the sample was determined by gas chromatography-mass spectrometry. The pretreatment of the sample to be tested is as follows: sodium hydroxide solution is added to the sample to be tested; the volume of sodium hydroxide solution added is 4 to 8 times the mass of the sample to be tested. The gas chromatography conditions were as follows: VF-624ms column, 30m × 0.320mm, 1.8μm; injection method: purge injection; injection port temperature: 250℃~270℃; scan mode: Scan; column temperature: initial temperature 50℃~60℃, hold for 2 min, increase to 150℃~170℃ at a rate of 15℃~20℃ / min, hold for 0 min, increase to 250℃~260℃ at a rate of 40℃~50℃ / min, hold for 2 min; column flow rate: 1.5mL / min; split ratio: 50:

1.

2. The method according to claim 1, characterized in that: The sample to be tested is either solid waste or extract.

3. The method according to claim 1, characterized in that: The purge and trap conditions were as follows: purge and trap injection, purge temperature: 45℃~50℃, purge time: 11 min, purge flow rate: 40 mL / min, baking time: 2 min, baking temperature: 250℃~270℃, desorption time: 2 min, desorption temperature: 240℃~250℃.

4. The method according to claim 1, characterized in that: The mass spectrometry conditions were as follows: scan range: 40~100 aum, ionization energy: 70 eV, scan mode: SCAN, ion source temperature: 230℃, quadrupole temperature: 150℃, interface temperature: 280℃.

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