CN109696499B - High-sensitivity determination method for nitrosamine in water based on high-resolution mass spectrum - Google Patents

Abstract

The invention discloses a high-sensitivity determination method of nitrosamine in water based on high-resolution mass spectrometry, which is characterized by comprising the following steps: the method comprises the following steps: after sample pretreatment, a water sample is separated by a chromatographic column, detected in a high-resolution mass spectrum full-scanning mode, and quantified by an internal standard method, wherein the sample pretreatment comprises solid-phase extraction enrichment and nitrogen-blowing quantitative concentration. The method has the detection Limit (LOD) of 0.05-0.5 ng/L and the quantitative Limit (LOQ) of 0.1-1.0 ng/L for different substances, which are far lower than the limit level of countries in the world at present, the linear range of 0.2-500 mug/L and the correlation coefficient (R)²) Is 0.9943 to 0.9997.

Description

High-sensitivity determination method for nitrosamine in water based on high-resolution mass spectrum

Technical Field

The invention relates to a method for measuring chemical substances, in particular to a method for measuring nitrosamine in water with high sensitivity based on high resolution mass spectrometry.

Background

Nitrosamines are a class of contaminants having the structure-N ═ O, and about 90% of over 300 nitrosamines found to date have carcinogenic effects. In recent years, it has been detected in beer, bacon products, cosmetics, tobacco, and latex products. Nitrosamines are known as "PM 2.5 in water" and found in river water, underground water, sewage and drinking water, and it has been found that the disinfection process including chlorine dioxide, ozone and chlorine combined with ultraviolet rays and the like may cause nitrosamines to containThe amount increases. The safety problem of nitrosamines in drinking water has been increasingly emphasized, and the international agency for research on cancer (IARC) has listed N-Nitrosodimethylamine (NDMA) and N-Nitrosodiethylamine (NDEA) as class 2A carcinogens and listed N-Nitrosodipropylamine (NDPA), N-Nitrosomethylethylamine (NMEA), N-Nitrosomorpholine (NMOR), N-Nitrosopyrrole (NPYR), N-Nitrosopiperidine (NPIP) and N-Nitrosodibutylamine (NDBA) as class 2B carcinogens. The Environmental Protection Agency (EPA) specifies the highest allowable concentrations in water of NDEA, NDMA, NDBA and NPYR (carcinogenic risk up to 10)^-5Time) are 2, 7, 60 and 200ng/L respectively; the state of California specifies NDMA, NDEA and NDPA limits of 10ng/L in drinking water; the maximum residual limit of NDMA and NMOR is specified in Germany to be 10 ng/L; the national Canadian Standard specifies an NDMA limit of 40 ng/L. China also needs to provide a limit standard of nitrosamine in drinking water.

Because the limit and the content of the nitrosamine in the water are extremely low, a pretreatment step of pre-enrichment and concentration is necessary. In reported pretreatment technologies such as liquid-liquid extraction (LLE), solid-phase extraction (SPE), solid-phase microextraction (SPME) and the like, the SPE can extract a large-volume water sample, has the characteristics of good reproducibility, high concentration multiple and the like, is suitable for extracting nitrosamine in various types of water bodies, can select a suitable filler according to the type of the water sample, and is a main means for extracting nitrosamine in water. The existing detection methods of nitrosamines in water include liquid chromatography (HPLC), liquid chromatography-mass spectrometry (HPLC-MS), Gas Chromatography (GC), gas chromatography-mass spectrometry (GC-MS) and the like, and for example, the national standard HJ 809-. Researches find that the selectivity of the detection by adopting simple chromatography or low-resolution mass spectrometry is poor, the detection is easy to overlap with an interference compound, and false positive is generated; among them, GC-MS (electron impact ionization source) is easy to generate indiscriminate ion fragments, which brings difficulty to the discrimination of interferents and targets.

Disclosure of Invention

The invention aims to provide a high-sensitivity determination method for nitrosamine in water based on high-resolution mass spectrometry.

The invention combines SPE with gas chromatography-electrostatic field orbit trap high resolution mass spectrometry to establish a method for detecting 16 kinds of trace nitrosamines in drinking water. Firstly, optimizing the chromatographic mass spectrum condition to improve the detection sensitivity of the instrument, optimizing the SPE extraction condition by designing an orthogonal test, then evaluating the quantitative limit, linearity, recovery rate, precision and the like of the method, and finally applying the method to the actual water sample determination.

A high-sensitivity determination method for nitrosamine in water based on high-resolution mass spectrometry comprises the following steps: after sample pretreatment, a water sample is separated by a chromatographic column, detected in a high-resolution mass spectrum full-scanning mode, and quantified by an internal standard method, wherein the sample pretreatment comprises solid-phase extraction enrichment and nitrogen-blowing quantitative concentration.

The invention relates to a high-sensitivity determination method for nitrosamine in water based on high-resolution mass spectrometry, wherein the sample pretreatment process specifically comprises the following steps: adding 50 mu L of 0.5mg/L internal standard solution into 1L of water sample, uniformly mixing and standing, activating a Chromabond HR-P solid phase extraction column by using 5mL of methanol sequentially, balancing 5mL of water, then enabling the water sample to flow through the column at a flow rate of about 3mL/min, draining for 1min after sample loading is finished, eluting by using 10mL of ethyl acetate, collecting eluent, adding anhydrous sodium sulfate for dehydration, and finally blowing and quantitatively concentrating supernatant liquid nitrogen to 0.5mL for on-machine determination.

The invention relates to a high-sensitivity determination method of nitrosamine in water based on high-resolution mass spectrum, wherein the nitrosamine is N-nitrosodimethylamine, N-nitrosomethylethylamine, N-nitrosodiethylamine, N-nitrosodiisopropylamine, N-nitrosodipropylamine, N-nitroso-N-methylaniline, N-nitrosodiisobutylamine, N-nitroso-N-ethylaniline, N-nitrosopyrrolidine, N-nitrosomorpholine, N-nitrosopiperidine, N-nitrosodibutylamine, N-nitrosodiphenylamine, N-nitrosodicyclohexylamine, N-nitroso-N.N (3.5.5-trimethylhexyl) amine and N-nitrosobenzylamine.

The invention relates to a high-sensitivity determination method for nitrosamine in water based on high-resolution mass spectrometry, wherein the chromatographic conditions are as follows: DB-35MS column, 30m × 0.25mm × 0.25 μm; carrier gas high-purity helium gas, 99.999%; the sample injection volume is 1 mu L; injecting a sample without pulse shunting, wherein the pulse pressure is 200kPa, and the pulse time is 1 min; the flow rate of the carrier gas is 2.0 mL/min; the sample inlet temperature is 250 ℃, and the transmission line temperature is 250 ℃; temperature programming: the initial temperature was 40 deg.C, held for 1min, then ramped up to 270 deg.C at a rate of 15 deg.C/min, held for 5 min.

The invention relates to a high-sensitivity determination method for nitrosamine in water based on high-resolution mass spectrum, wherein the mass spectrum conditions are as follows: resolution 60000FWHM, 200 m/z; EI ionization source, ion source temperature 280 ℃; delaying the solvent for 3 min; the full scanning mode has a scanning range of 40-300 m/z.

The invention relates to a high-sensitivity determination method of nitrosamine in water based on high-resolution mass spectrometry, which comprises the following steps:

the qualitative and quantitative ions of 16 nitrosamines and 2 internal standards are shown in table 1:

TABLE 116 Retention time, quantitative and qualitative ions of nitrosamine species and two internal standards

^aExpressed as NDMA-d₆Quantifying for an internal standard;^bexpressed as NDPA-d₁₄Quantifying for an internal standard; NA^cIndicating that the data is not provided.

The invention relates to a high-sensitivity determination method of nitrosamine in water based on high-resolution mass spectrometry, which is different from the prior art in that: the method mainly adopts gas chromatography-high resolution mass spectrometry (the resolution can reach 12 ten thousand at most) to measure the trace 16 nitrosamines in the water, so that the accurate mass number of each substance can be obtained, and the fifth position is accurate to a decimal point (the conventional mass spectrometry is low resolution and can only detect the next position of the decimal point). The advantage 1 is high sensitivity, and the comparison in the text table 6 shows that the detection limit is lower than ng/L level, which is superior to the existing domestic and foreign technologies. The method has the advantages that 2, the method is more accurate in substance detection (for example, the peak after 102.02931 ions are extracted is definitely cleaner than the peak after 102 ions are extracted, namely, the selectivity is higher), the mass error is less than or equal to 1.839ppm, and therefore, the method has high selectivity and accuracy for target substances and obviously reduces the detection result of false positive of the conventional low-resolution mass spectrum. High sensitivity and high accuracy are advantages that are characteristic of the use of high resolution mass spectrometry.

After the experimental water sample is subjected to solid-phase extraction enrichment and nitrogen-blowing quantitative concentration, DB-35MS chromatographic column separation, high-resolution mass spectrum full-scanning mode detection and internal standard method quantification are carried out. The chromatographic separation conditions, the temperature of a mass spectrum ion source, the flow rate of a chromatographic carrier gas, the sample introduction mode, the pulse pressure and the like of the method are optimized, and the optimal conditions are that the temperature of the ion source is 280 ℃, the flow rate of the carrier gas is 2.0mL/min, the pulse is not shunted and the pulse pressure is 200 kPa. The best solid phase extraction conditions obtained by a four-factor three-level orthogonal experiment are Chromabond HR-P extraction column and 10mL ethyl acetate elution. The result shows that the detection Limit (LOD) of the method for different substances is 0.05-0.5 ng/L, the quantitative Limit (LOQ) is 0.1-1.0 ng/L, which is far lower than the limit level of countries in the world at present, the linear range is 0.2-500 mug/L, and the correlation coefficient (R) is²) Is 0.9943 to 0.9997. The recovery rate of the standard addition of 4 different levels is 72.4% -114.8%, and the relative standard deviation (RSD, n is 6) is 0.8% -9.5%. And finally, measuring 12 actual water samples collected in Beijing areas, wherein 5 kinds of nitrosamines are detected, and the content is 0.9-20.4 ng/L. The method is high in sensitivity, selectivity and accuracy, and is suitable for the confirmatory detection of the trace nitrosamine in water.

The method for measuring nitrosamine in water based on high resolution mass spectrometry in high sensitivity is further explained in the following by combining the attached drawings.

Drawings

FIG. 1 is a total ion flow chromatogram of 16 nitrosamines of the invention after separation by different chromatographic columns; wherein the numbering of each substance is the same as in table 1, a: HP-5MS, B: DB-35MS, C: DB-624, D: DB-WAX;

FIG. 2 is an extracted ion flow chromatogram of 18 nitrosamine species (containing two internal standards) in accordance with the present invention;

FIG. 3 is a comparison graph of chromatographic and mass spectral parameter optimization according to the present invention; a: ion source temperature, B: carrier gas flow rate, C: pulse pressure.

Detailed Description

First, experimental part

1. Instruments and reagents

Q active GC Orbitrap type gas chromatography-quadrupole-electrostatic field Orbitrap mass spectrometer equipped with Triplus RSH autosampler (Thermo Fisher, USA); model 7890N-5977B gas chromatography-mass spectrometer (Agilent, USA); TurboVap model II automatic nitrogen-blown concentrator (Biotage, USA); solid phase extraction apparatus (Supelco, USA); chromabond Easy, Chromabond HR-P extraction column (500mg, 6mL, MN, Germany); supelclean ENVI-Chrom P extraction column (250mg, 6mL, Supelco, USA).

16 nitrosamines and 2 internal standards NDMA-d₆And NDPA-d₁₄The standard substance is purchased from suppliers such as TCI, Sigma, Dr. Ehrenstontorfer, Manhage, TRC and the like, and the purity of the standard substance is more than 95 percent; n-hexane, ethyl acetate, acetone, methanol (chromatographically pure, american j.t.baker); anhydrous sodium sulfate (analytical pure, Beijing chemical reagents, Inc.); the experimental water was ultrapure water prepared by a Milli-Q purification system (Millipore, USA).

2. Standard solution preparation

Respectively weighing 50mg of standard substance, dissolving with methanol and fixing the volume to a 50mL brown volumetric flask to obtain 1000mg/L single-standard stock solution. Ethyl acetate is used for preparing 10mg/L of 16N-nitrosamine mixed stock solutions and 2 internal standard mixed stock solutions, and further 0.5mg/L of internal standard working solution is prepared for being stored in a dark place at-18 ℃. When in use, the mixed working solution is diluted to 0.01 mu g/L-500 mu g/L by ethyl acetate according to needs, wherein the internal standard NDMA-d₆And NDPA-d₁₄The concentrations of (A) and (B) were all 50. mu.g/L.

3. Drawing of standard curve

Diluting the 10mg/L mixed stock solution with ethyl acetate step by step, preparing 0.2-500.0 mu g/L series standard solutions, wherein the concentration of an internal standard substance is 50 mu g/L, respectively measuring, taking the ratio of the quantitative ion peak area of the object to be measured to the quantitative ion peak area of the corresponding internal standard substance as a vertical coordinate (y), taking the on-machine concentration of the object to be measured as a horizontal coordinate (x), and drawing a standard curve.

4. Sample pretreatment

50 mu L of 0.5mg/L internal standard solution is added into 1L of water sample, and then the mixture is mixed and kept stand. The Chromabond HR-P solid phase extraction column is sequentially activated by 5mL of methanol and 5mL of water is balanced, then a water sample flows through the column at a flow rate of about 3mL/min, and after the sample loading is finished, the water sample is drained for 1 min. Eluting with 10mL ethyl acetate, collecting eluate, adding anhydrous sodium sulfate for dehydration, and blowing liquid nitrogen to quantitatively concentrate the supernatant to 0.5mL for measurement on the machine.

5. Detection conditions

Chromatographic conditions are as follows: DB-35MS column (30m × 0.25mm × 0.25 μm); carrier gas high purity helium (99.999%); the sample volume is 1 mu L; injecting a sample without pulse shunting, wherein the pulse pressure is 200kPa, and the pulse time is 1 min; the flow rate of the carrier gas is 2.0 mL/min; the sample inlet temperature is 250 ℃, and the transmission line temperature is 250 ℃; temperature programming: the initial temperature was 40 deg.C, held for 1min, then ramped up to 270 deg.C at a rate of 15 deg.C/min, held for 5 min.

Mass spectrum conditions: resolution 60000FWHM (200 m/z); EI ionization source, ion source temperature 280 ℃; delaying the solvent for 3 min; in Full Scan mode (Full-Scan), the Scan range is 40-300 m/z. The qualitative and quantitative ions of 16 nitrosamines and 2 internal standards are shown in Table 1.

TABLE 118 Retention time, quantitative and qualitative ions of nitrosamine species (containing 2 internal standards)

^aExpressed as NDMA-d₆Quantifying for an internal standard;^bexpressed as NDPA-d₁₄Quantifying for an internal standard; NA^cIndicating that the data is not provided.

Second, results and analysis

1. Chromatography-mass spectrometry condition optimization

Using conventional low-resolution gas chromatography, 4 kinds of columns were examined, namely, low-polarity HP-5MS (30 m.times.0.25 mm.times.0.25 μm), medium-polarity DB-35MS (30 m.times.0.25 mm.times.0.25 μm), medium-polarity DB-624(30 m.times.0.25 mm.times.1.4 μm), and high-polarity DB-WAX (30 m.times.0.25 mm. times.0.25 μm) for the separation of 16 kinds of nitrosamines. As shown in FIG. 1, the chromatographic columns DB-624 and DB-WAX have better separation effect, however, DB-624 has low response to the substance 3/14/15/16, and the sensitivity of the chromatographic columns is obviously influenced during the detection process; DB-WAX cannot separate 6/8 two species, but the two species have the same monitoring ion 106.065, which are difficult to detect separately without separation; HP-5MS separation was the least effective, and substance 1/14/15 response was low; DB-35MS has better response to each substance, can effectively separate the co-flow chromatographic peak by extracting characteristic ions, does not influence the qualitative and quantitative properties, and has better thermal stability of the chromatographic column (340 ℃). Therefore, DB-35MS chromatographic columns are selected for subsequent research.

The Q active-GC mass spectrometer can achieve the acquisition rate of more than 7 spectrograms per second in a full scan under the resolution of 60000, so that the data can obtain enough scanning points; meanwhile, the quality error is within 1ppm, and the stability and the reliability of data are ensured. The European Union EC/657/2002 has to reach 4 confirmation points (IP) for qualitative requirements of mass spectra, the high-resolution mass spectra carries out full-scan measurement on accurate mass numbers, each ion is defined as 2 confirmation points, and the confirmation points of one quantitative ion and one auxiliary qualitative ion can reach 4, thereby realizing simultaneous quantitative and qualitative confirmation. The quantitative and auxiliary qualitative ions of 16 nitrosamines and 2 internal standards are shown in Table 1, and the extracted ion flow diagram of each substance is shown in FIG. 2.

In order to obtain higher sensitivity, the temperature of the mass spectrum ion source, the flow rate of chromatographic carrier gas, the sample injection mode and the pulse pressure are optimized. As can be seen from FIG. 3A, the peak area of each substance increases with the increase of the temperature of the ion source, and remains relatively stable after 280 ℃, and the higher temperature is beneficial to improving the ionization efficiency and properly improving the peak tailing phenomenon. FIG. 3B shows that a larger carrier gas flow rate helps to increase the peak-off time of the substance, thereby obtaining a sharper peak pattern to reduce the peak tailing phenomenon, and most substance response values are higher when the carrier gas flow rate is 2.0 mL/min. It can be seen from fig. 3C that the effect of pulse non-shunting is better than that of non-pulse, because the pulse sample injection mode applies higher pressure on the sample injection port, so that the substance can rapidly enter the chromatographic column, the decomposition and loss at the sample injection port are reduced, and the sharp and symmetrical peak type is obtained. By optimising the pulse pressure it was found that the peak was reached at 200kPa and then settled, so the pulse was chosen not to be split and the pulse pressure was 200 kPa.

2. Optimization of solid phase extraction conditions

Three SPE columns with styrene-divinylbenzene copolymer as filler were selected for the orthogonal experiments, Chromabond HR-P, Supelclean ENVI-Chrom P and Chromabond Easy, respectively. The N-octanol-water distribution coefficient (lgkow) of the 16N-nitrosamines ranges from-0.57 to 3.90, and the water solubility and the oil solubility are distributed, so that 3 elution solvents with different lgkow values are selected, namely N-hexane, ethyl acetate and acetone, wherein the N-hexane (3.29) is lipophilic, the ethyl acetate (0.86) is lipophilic and has certain hydrophilicity, and the acetone (-0.24) is hydrophilic.

A four-factor three-level orthogonal table (L9(34)) is selected to optimize the solid phase extraction conditions, the experimental design is shown in table 2, and the recovery rate of 100mL of aqueous solution with the extraction nitrosamine content of 1 mu g/L (converted into the concentration of the solution to be detected of 200 mu g/L) under each experimental condition is examined. The results are shown in Table 3, and it is possible that the recovery of each nitrosamine is better when ethyl acetate is used as the eluting solvent, because ethyl acetate dissolves and elutes the target substance both well. And the n-hexane has stronger lipophilicity and poorer solubility to hydrophilic nitrosamines such as NDMA, so that the recovery rate of the substance is extremely poor. Of the 9 orthogonal experiments, the recovery of experiment 2(A1B2C2) was relatively good; and performing range analysis on the experimental result to obtain the optimal solid phase extraction conditions of each analyte, wherein the optimal solid phase extraction conditions of other nitrosamines except NDBA are consistent, and only the elution amount is distributed on two levels, namely 8mL and 10 mL. After that, a verification experiment is carried out by using a Chromabond HR-P column, 8mL and 10mL ethyl acetate, and the result shows that the recovery rate of 10mL ethyl acetate is better, and all substances reach more than 88%. Thus, the selected solid phase extraction conditions were a Chromabond HR-P extraction column, eluting with 10mL of ethyl acetate.

TABLE 2 solid-phase extraction orthogonal test factor level table

TABLE 3 solid phase extraction Quadrature test results

3. Methodology investigation

3.1 Linear Range, detection Limit and quantitative lower Limit

And (3) sequentially injecting mixed standard solutions (containing internal standards with the same concentration) with different concentrations from low concentration to high concentration, and drawing a standard curve. The detection limits of 16 nitrosamine substances are determined by 3 times of signal-to-noise ratio (S/N is more than or equal to 3), an internal standard method is adopted for quantification, the quantification limit of the method is obtained by using S/N is more than or equal to 10, and the results are shown in Table 4. The result shows that each substance has a correlation coefficient R within a linear range of 0.2-500 mu g/L²Not less than 0.9943, LOD 0.05-0.5 ng/L, LOQ 0.1-1.0 ng/L.

TABLE 416 Linear Range, correlation coefficient, detection limits and quantitation limits for nitrosamine species

3.2 Process recovery and precision

And adding 4 nitrosamine mixed standards with different concentrations into a blank water sample to perform parallel processing for 6 times. From the results in table 5, it is clear that the recovery rate of the method for different substances is between 72.4% and 114.8%, and the relative standard deviation (RSD, n ═ 6) is between 0.8% and 9.5%.

Compared with the reported detection method of nitrosamine in water (Table 6), the method established in the invention has the advantages that the number of nitrosamine substances is large (16 types), the detection limit is low (0.05-0.5 ng/L), the recovery rate is good, more importantly, the qualitative and quantitative ion mass errors of all the substances are less than 1.839ppm through adopting high-resolution mass spectrometry, the stability and reliability of data are ensured, and 4 confirmation points specified by European Union EC/657/2002 are reached, so that when the trace nitrosamine is detected, the method can effectively eliminate matrix interference and has high accuracy and sensitivity.

TABLE 516 recovery and precision of nitrosamines

Table 6 comparison with the prior art reference for nitrosamine detection in water

3.3 actual Water sample detection

By applying the method, 12 running water samples in different areas such as Tokyo, Hai lake, Chaoyang, Shijing mountain, Tongzhou and Daxing in Beijing city are measured (see Table 7). As a result, 5 nitrosamines NMPhA, NEPhA, NMOR, NDPhA and NDBzA were detected, wherein NMOR was detected only in S1(sample 1), and was 0.9ng/L, which is lower than the German limit of 10 ng/L; for other detected nitrosamines, the limited requirements are not available at home and abroad at present, and attention needs to be paid to the nitrosamines.

TABLE 7 actual water sample test results

The method establishes a solid phase extraction-gas chromatography high-resolution mass spectrometry detection method for 16 kinds of trace nitrosamines in drinking water. Under the optimized instrument detection condition and the solid-phase extraction condition, the detection Limit (LOD) of 16 substances is only 0.05-0.50 ng/L and is far lower than the limit level of each country at present, simultaneously, the high-resolution mass spectrum has ultrahigh mass precision, the mass number of monitoring ions of each substance is accurate to 0.00001, and the mass error is less than or equal to 1.839ppm, so that the method has very high selectivity and accuracy, is suitable for the confirmation detection of the trace nitrosamine in water, and provides reference for the detection of other trace substances.

The above-mentioned embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solution of the present invention by those skilled in the art should fall within the protection scope defined by the claims of the present invention without departing from the spirit of the present invention.

Claims (3)

1. A high-sensitivity determination method for nitrosamine in water based on high-resolution mass spectrometry is characterized by comprising the following steps: the method comprises the following steps: after sample pretreatment, a water sample is separated by a chromatographic column, detected in a high-resolution mass spectrum full-scanning mode, and quantified by an internal standard method;

the sample pretreatment specifically comprises the following steps: adding 50 mu L of 0.5mg/L internal standard solution into 1L of water sample, uniformly mixing and standing, activating a Chromabond HR-P solid phase extraction column by using 5mL of methanol in sequence, balancing 5mL of water, then enabling the water sample to flow through the column at a flow rate of about 3mL/min, draining for 1min after sample loading is finished, eluting by using 10mL of ethyl acetate, collecting eluent, adding anhydrous sodium sulfate for dehydration, and finally blowing and quantitatively concentrating supernatant liquid nitrogen to 0.5mL for on-machine determination;

the chromatographic conditions were as follows: DB-35MS column, 30m × 0.25mm × 0.25 μm; carrier gas high-purity helium gas, 99.999%; the sample injection volume is 1 mu L; injecting a sample without pulse shunting, wherein the pulse pressure is 200kPa, and the pulse time is 1 min; the flow rate of the carrier gas is 2.0 mL/min; the sample inlet temperature is 250 ℃, and the transmission line temperature is 250 ℃; temperature programming: the initial temperature is 40 ℃, the temperature is kept for 1min, then the temperature is increased to 270 ℃ at the speed of 15 ℃/min, and the temperature is kept for 5 min;

the nitrosamine is N-nitrosodimethylamine, N-nitrosomethylethylamine, N-nitrosodiethylamine, N-nitrosodiisopropylamine, N-nitrosodipropylamine, N-nitroso-N-methylaniline, N-nitrosodiisobutylamine, N-nitroso-N-ethylaniline, N-nitrosopyrrolidine, N-nitrosomorpholine, N-nitrosopiperidine, N-nitrosodibutylamine, N-nitrosodiphenylamine, N-nitrosodicyclohexylamine, N-nitroso-N.N (3.5.5-trimethylhexyl) amine and N-nitrosodibenzylamine.

2. The method for high-sensitivity determination of nitrosamines in water based on high resolution mass spectrometry as claimed in claim 1, wherein: the mass spectrometry conditions were as follows: resolution 60000FWHM, 200 m/z; EI ionization source, ion source temperature 280 ℃; delaying the solvent for 3 min; the full scan mode has a scan range of 40-300 m/z.

3. The method for high-sensitivity determination of nitrosamines in water based on high resolution mass spectrometry as claimed in claim 2, wherein: the qualitative and quantitative ions of 16 nitrosamines and 2 internal standards are shown in table 1:

TABLE 116 Retention time, quantitative and qualitative ions of nitrosamine species and two internal standards

^aExpressed as NDMA-d₆Quantifying for an internal standard;^bexpressed as NDPA-d₁₄Quantifying for an internal standard; NA^cIndicating that the data is not provided.

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