Method for detecting content of hydrogen sulfide in acetylcysteine solution by gas chromatography

Abstract

The invention belongs to the technical field of drug detection, and particularly relates to a method for detecting the content of hydrogen sulfide in an acetylcysteine solution by a gas chromatography. The method comprises the following steps: taking polyethylene glycol 20M as a capillary column of a stationary liquid; the column temperature is 30-50 DEG C; the flow rate of the chromatographic column is 1.0 ml / min to 2.0 ml / min; the temperature of a sample inlet is 170-190 DEG C; the method for detecting the content of the hydrogen sulfide in the acetylcysteine solution is simple and convenient to operate, high in sensitivity, good in precision and high in specificity, the retention time of a hydrogen sulfide peak is 4.5 minutes, and the analysis time is short. The method has the advantages that the recovery rate is high, the average recovery rate is 96.1%, the sensitivity is high, and the quantitation limit reaches 0.2 microgram; the stability of the solution can reach 31 hours, and the content of hydrogen sulfide in the acetylcysteine solution can be rapidly determined.

Description

Technical Field

[0001] The invention belongs to the technical field of drug detection, and particularly relates to a method for detecting the content of hydrogen sulfide in an acetylcysteine ​​solution by gas chromatography. Background Art

[0002] N-acetylcysteine ​​(NAC) is an important drug and health product, widely used in expectorant, anti-oxidation, liver protection and other fields. However, N-acetylcysteine ​​is easily decomposed to produce hydrogen sulfide (H2S) during production and storage. Hydrogen sulfide is a toxic gas, and even trace amounts can affect the safety and effectiveness of drugs. Therefore, it is crucial to establish a rapid, sensitive and accurate method for detecting hydrogen sulfide content in N-acetylcysteine ​​solution.

[0003] At present, the methods for detecting hydrogen sulfide mainly include: 1. Chemical analysis method: such as methylene blue method, iodine titration method, etc. These methods are cumbersome to operate, low in sensitivity, and susceptible to interference. 2. Electrochemical sensor method: Although the operation is simple, the sensor is easily affected by the environment, has poor stability, and is difficult to achieve trace detection. 3. Gas chromatography: It has the advantages of high separation efficiency, high sensitivity, and good selectivity, and is an ideal method for detecting hydrogen sulfide.

[0004] However, the existing gas chromatography method still has the following shortcomings when detecting hydrogen sulfide in acetylcysteine ​​solution: complex sample pretreatment: derivatization step is required, the operation is cumbersome, and errors are easily introduced. Insufficient detection sensitivity: it is difficult to meet the detection requirements of trace hydrogen sulfide. Poor method specificity: it is difficult to effectively separate and detect the interference of other sulfur-containing compounds in acetylcysteine ​​solution. Summary of the invention

[0005] In order to solve the problems in the prior art, the present invention provides a method for detecting the content of hydrogen sulfide in an acetylcysteine ​​solution by gas chromatography, so as to achieve the purpose of simple operation, high sensitivity, good precision and strong specificity in detecting the content of hydrogen sulfide in the acetylcysteine ​​solution.

[0006] The present invention solves the technical problem by adopting the following technical solutions:

[0007] The present invention aims to provide a method for detecting the content of hydrogen sulfide in an acetylcysteine ​​solution by gas chromatography, comprising a capillary column with polyethylene glycol 20M as a stationary liquid; a column temperature of 30°C to 50°C; a chromatographic column flow rate of 1.0ml / min to 2.0ml / min; an injection port temperature of 170°C to 190°C; and a split ratio of 1 to 5:1.

[0008] Furthermore, the detector is FPD; the detector temperature is 190°C to 210°C; the headspace equilibrium temperature is 70°C to 90°C; and the headspace equilibrium time is 15min to 45min.

[0009] Furthermore, it also includes preparing a sodium sulfide solution with a concentration of 0μg / ml to 4μg / ml, measuring 1.0ml of sodium sulfide solution of different concentrations, placing them in 20ml headspace bottles respectively, and adding 0.2ml to 0.6ml of 0.5mol / L sulfuric acid solution as a reference solution.

[0010] Furthermore, the method further comprises measuring 1.0 ml of the acetylcysteine ​​sample solution, placing it in a 20 ml headspace bottle, adding 0.2 ml to 0.6 ml of 0.5 mol / L sulfuric acid, and sealing the bottle as the test solution.

[0011] Furthermore, the capillary column has a membrane thickness of 0.25 μm to 2 μm, a column length of 30 m to 60 m, and an inner diameter of 0.25 mm to 0.53 mm. The preferred specification is 1.00 μm thick and 30 m×0.53 mm.

[0012] Further, the chromatographic conditions are: capillary column temperature is 40°C; column flow rate is 1.5 ml / min; injection port temperature is 180°C; split ratio is 2:1; detector temperature is 200°C; headspace equilibrium temperature is 80°C; headspace equilibrium time is 30 min;

[0013] Sodium sulfide solutions with concentrations of 0.3μg / ml, 0.5μg / ml, 1.0μg / ml, 1.5μg / ml, 2.0μg / ml, and 4.0μg / ml were prepared respectively, 1.0ml was measured and placed in a 20ml headspace bottle, 0.4ml of 0.5mol / L sulfuric acid was added, and the solution was sealed as a reference solution;

[0014] Measure 1.0 ml of acetylcysteine ​​sample solution, place it in a 20 ml headspace bottle, add 0.4 ml of 0.5 mol / L sulfuric acid, and seal it as the test solution.

[0015] Furthermore, the hydrogen sulfide content is calculated as follows:

[0016] 1. Log 10 C is the ordinate, log 10 A is the horizontal axis, and the linear regression equation is calculated:

[0017] Linear regression equation: log 10 C=K×log 10 A+b;

[0018] Where: C: concentration of reference solution, μg / ml;

[0019] A: peak area of ​​reference solution;

[0020] 2. Calculate the content of hydrogen sulfide in the test solution according to the linear equation:

[0021]

[0022] Where: A S : The peak area of ​​hydrogen sulfide in the test solution;

[0023] C S : Concentration of acetylcysteine ​​in the test solution, g / ml;

[0024] K: slope of the linear regression equation;

[0025] b: intercept of the linear regression equation.

[0026] Compared with the prior art, the beneficial technical effects of the present invention are:

[0027] 1. The present invention provides a gas chromatography detection method for detecting the content of hydrogen sulfide in an acetylcysteine ​​solution, which realizes a hydrogen sulfide peak retention time of 4.5 minutes and a short analysis time. The method has a high recovery rate, an average recovery rate of 96.1%, high sensitivity, and a quantitative limit of 0.2 μg; the stability of the solution can reach 31 hours, and the content of hydrogen sulfide in the acetylcysteine ​​solution can be quickly determined.

[0028] 2. Simplify sample pretreatment: Use direct injection or simple dilution and filtration steps to simplify operation and reduce errors.

[0029] 3. Improve detection sensitivity: Optimize chromatographic conditions and use high-sensitivity detectors to detect trace amounts of hydrogen sulfide.

[0030] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above contents of the present invention and its objectives, features and advantages more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is the hydrogen sulfide chromatogram of the present invention, and the retention time of hydrogen sulfide is 4.5 minutes (the chromatogram obtained using the chromatographic conditions in Example 1).

[0032] Figure 2 It is the linear curve diagram of the hydrogen sulfide reference substance in the present invention. DETAILED DESCRIPTION

[0033] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only exemplary illustrations and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are included in the scope that the present invention is intended to protect.

[0034] In addition, unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0035] Main instruments and chromatographic conditions:

[0036] Gas chromatograph; equipped with FPD detector, headspace sampler, Lab Solutions CS chromatography workstation.

[0037] Chromatographic column: capillary column with polyethylene glycol 20M as stationary liquid.

[0038] Reagents and drugs: sodium sulfide, sulfuric acid, iodine titrant (0.05 mol / L), sodium thiosulfate titrant (0.1 mol / L), acetylcysteine ​​injection.

[0039] The water used in the experiments was homemade purified water.

[0040] Example 1

[0041] A method for determining the hydrogen sulfide content in an acetylcysteine ​​solution is achieved by the following steps:

[0042] Preparation of sample solution: Accurately measure acetylcysteine ​​injection and use water to make a solution containing about 5 mg of acetylcysteine ​​per 1 ml. Accurately measure 1.0 ml and place it in a 20 ml headspace bottle. Add 0.4 ml of 0.5 mol / L sulfuric acid and seal it as the test solution.

[0043] Starch indicator solution: accurately weigh 0.5g of soluble starch, add 5ml of water and stir well, then slowly pour into 100ml of boiling water, stirring while adding, continue boiling for 2min, cool, and pour off the upper clear layer. This solution should be prepared freshly before use.

[0044] 0.4% sodium sulfide solution calibration: accurately measure 12.5ml of 0.4% sodium sulfide solution, add 4ml of hydrochloric acid, accurately add 12.5ml of iodine titrant (0.05mol / L), shake well; titrate with sodium thiosulfate titrant (0.1mol / L) until yellow, add 0.5ml of starch indicator solution, continue titrating until blue disappears, and make blank correction. Each 1ml of sodium thiosulfate titrant (0.1mol / L) is equivalent to 68.16μg / ml of hydrogen sulfide.

[0045] Preparation of reference solution: accurately measure an appropriate amount of 0.4% sodium sulfide solution, dilute with water to make solutions containing about 0.3μg, 0.5μg, 1.0μg, 1.5, 2.0μg, and 4.0μg of hydrogen sulfide per 1ml, accurately measure 1.0ml of each, place in a 20ml headspace bottle, add 0.4ml of 0.5mol / L sulfuric acid, and seal. This is used as reference solution 1 to 6.

[0046] The chromatographic conditions are as follows: column temperature is 40°C; column flow rate is 1.5 ml / min; injection port temperature is 180°C; split ratio is 2:1, detector is FPD detector; detector temperature is 200°C; headspace equilibrium temperature is 80°C; headspace equilibrium time is 30 min.

[0047] The reference solution and the test solution were tested under the above chromatographic conditions and calculated according to the following formula

[0048] 0.4% sodium sulfide solution calibration calculation formula:

[0049]

[0050] Where: C RX : Concentration of reference substance stock solution, g / ml;

[0051] V0: blank consumption of sodium thiosulfate titrant volume, ml;

[0052] C: concentration of sodium thiosulfate titrant, mol / L;

[0053] V: volume of sodium thiosulfate titration solution consumed by the reference substance stock solution, ml;

[0054] 0.1: Theoretical concentration of sodium thiosulfate titrant, mol / L;

[0055] Hydrogen sulfide content calculation formula:

[0056] 1 in log 10 C is the ordinate, log 10 A is the horizontal axis, and the linear regression equation is calculated.

[0057] Linear regression equation: log 10 C=K×log 10 A+b

[0058] Where: C: concentration of reference solution, μg / ml;

[0059] A: peak area of ​​reference solution;

[0060] 2 Calculate the content of hydrogen sulfide in the test solution according to the linear equation.

[0061]

[0062] Where: A S : The peak area of ​​hydrogen sulfide in the test solution;

[0063] C S : Concentration of acetylcysteine ​​in the test solution, g / ml;

[0064] K: slope of the linear regression equation;

[0065] b: intercept of the linear regression equation;

[0066] The hydrogen sulfide content in the acetylcysteine ​​solution measured in this example is 81 ppm.

[0067] Example 2

[0068] A method for determining the hydrogen sulfide content in an acetylcysteine ​​solution is achieved by the following steps:

[0069] Preparation of sample solution: Accurately measure acetylcysteine ​​injection and use water to make a solution containing about 5 mg of acetylcysteine ​​per 1 ml. Accurately measure 1.0 ml and place it in a 20 ml headspace bottle. Add 0.4 ml of 0.5 mol / L sulfuric acid and seal it as the test solution.

[0070] Starch indicator solution: accurately weigh 0.5g of soluble starch, add 5ml of water and stir well, then slowly pour into 100ml of boiling water, stirring while adding, continue boiling for 2min, cool, and pour off the upper clear layer. This solution should be prepared freshly before use.

[0071] 0.4% sodium sulfide solution calibration: accurately measure 12.5ml of 0.4% sodium sulfide solution, add 4ml of hydrochloric acid, accurately add 12.5ml of iodine titrant (0.05mol / L), shake well; titrate with sodium thiosulfate titrant (0.1mol / L) until yellow, add 0.5ml of starch indicator solution, continue titrating until blue disappears, and make blank correction. Each 1ml of sodium thiosulfate titrant (0.1mol / L) is equivalent to 68.16μg / ml of hydrogen sulfide.

[0072] Preparation of reference solution: accurately measure an appropriate amount of 0.4% sodium sulfide solution, dilute with water to make solutions containing about 0.3μg, 0.5μg, 1.0μg, 1.5, 2.0μg, and 4.0μg of hydrogen sulfide per 1ml, accurately measure 1.0ml of each, place in a 20ml headspace bottle, add 0.4ml of 0.5mol / L sulfuric acid, and seal. This is used as reference solution 1 to 6.

[0073] The chromatographic conditions were as follows: column temperature was 30°C; column flow rate was 1.5 ml / min; injection port temperature was 170°C; split ratio was 5:1, and the detector was an FPD detector; detector temperature was 190°C; headspace equilibrium temperature was 70°C; and headspace equilibrium time was 45 min.

[0074] The reference solution and the test solution were tested under the above chromatographic conditions and calculated according to the following formula

[0075] 0.4% sodium sulfide solution calibration calculation formula:

[0076]

[0077] Where: C RX : Concentration of reference substance stock solution, g / ml;

[0078] V0: blank consumption of sodium thiosulfate titrant volume, ml;

[0079] C: concentration of sodium thiosulfate titrant, mol / L;

[0080] V: volume of sodium thiosulfate titration solution consumed by the reference substance stock solution, ml;

[0081] 0.1: Theoretical concentration of sodium thiosulfate titrant, mol / L;

[0082] Hydrogen sulfide content calculation formula:

[0083] 1 in log 10 C is the ordinate, log 10 A is the horizontal axis, and the linear regression equation is calculated.

[0084] Linear regression equation: log 10 C=K×log 10 A+b

[0085] Where: C: concentration of reference solution, μg / ml;

[0086] A: peak area of ​​reference solution;

[0087] 2 Calculate the content of hydrogen sulfide in the test solution according to the linear equation.

[0088]

[0089] Where: A S : The peak area of ​​hydrogen sulfide in the test solution;

[0090] C S : Concentration of acetylcysteine ​​in the test solution, g / ml;

[0091] K: slope of the linear regression equation;

[0092] b: intercept of the linear regression equation;

[0093] The hydrogen sulfide content in the acetylcysteine ​​solution measured in this example is 76 ppm.

[0094] Example 3

[0095] A method for determining the hydrogen sulfide content in an acetylcysteine ​​solution is achieved by the following steps:

[0096] Preparation of sample solution: Accurately measure acetylcysteine ​​injection and use water to make a solution containing about 5 mg of acetylcysteine ​​per 1 ml. Accurately measure 1.0 ml and place it in a 20 ml headspace bottle. Add 0.4 ml of 0.5 mol / L sulfuric acid and seal it as the test solution.

[0097] Starch indicator solution: accurately weigh 0.5g of soluble starch, add 5ml of water and stir well, then slowly pour into 100ml of boiling water, stirring while adding, continue boiling for 2min, cool, and pour off the upper clear layer. This solution should be prepared freshly before use.

[0098] 0.4% sodium sulfide solution calibration: accurately measure 12.5ml of 0.4% sodium sulfide solution, add 4ml of hydrochloric acid, accurately add 12.5ml of iodine titrant (0.05mol / L), shake well; titrate with sodium thiosulfate titrant (0.1mol / L) until yellow, add 0.5ml of starch indicator solution, continue titrating until blue disappears, and make blank correction. Each 1ml of sodium thiosulfate titrant (0.1mol / L) is equivalent to 68.16μg / ml of hydrogen sulfide.

[0099] Preparation of reference solution: accurately measure an appropriate amount of 0.4% sodium sulfide solution, dilute with water to make solutions containing about 0.3μg, 0.5μg, 1.0μg, 1.5, 2.0μg, and 4.0μg of hydrogen sulfide per 1ml, accurately measure 1.0ml of each, place in a 20ml headspace bottle, add 0.4ml of 0.5mol / L sulfuric acid, and seal. This is used as reference solution 1 to 6.

[0100] The chromatographic conditions were as follows: column temperature was 50°C; column flow rate was 1.5 ml / min; injection port temperature was 190°C; split ratio was 1:1, and the detector was an FPD detector; detector temperature was 210°C; headspace equilibrium temperature was 90°C; and headspace equilibrium time was 15 min.

[0101] The reference solution and the test solution were tested under the above chromatographic conditions and calculated according to the following formula

[0102] 0.4% sodium sulfide solution calibration calculation formula:

[0103]

[0104] Where: C RX : Concentration of reference substance stock solution, g / ml;

[0105] V0: blank consumption of sodium thiosulfate titrant volume, ml;

[0106] C: concentration of sodium thiosulfate titrant, mol / L;

[0107] V: volume of sodium thiosulfate titration solution consumed by the reference substance stock solution, ml;

[0108] 0.1: Theoretical concentration of sodium thiosulfate titrant, mol / L;

[0109] Hydrogen sulfide content calculation formula:

[0110] 1 in log 10 C is the ordinate, log 10 A is the horizontal axis, and the linear regression equation is calculated.

[0111] Linear regression equation: log 10 C=K×log 10 A+b

[0112] Where: C: concentration of reference solution, μg / ml;

[0113] A: peak area of ​​reference solution;

[0114] 2 Calculate the content of hydrogen sulfide in the test solution according to the linear equation.

[0115]

[0116] Where: A S : The peak area of ​​hydrogen sulfide in the test solution;

[0117] C S : Concentration of acetylcysteine ​​in the test solution, g / ml;

[0118] K: slope of the linear regression equation;

[0119] b: intercept of the linear regression equation;

[0120] The hydrogen sulfide content in the acetylcysteine ​​solution measured in this example is 85 ppm.

[0121] Example 4

[0122] A method for determining the hydrogen sulfide content in an acetylcysteine ​​solution is achieved by the following steps:

[0123] Preparation of sample solution: Accurately measure acetylcysteine ​​injection and use water to make a solution containing about 5 mg of acetylcysteine ​​per 1 ml. Accurately measure 1.0 ml and place it in a 20 ml headspace bottle. Add 0.2 ml of 0.5 mol / L sulfuric acid and seal it as the test solution.

[0124] Starch indicator solution: accurately weigh 0.5g of soluble starch, add 5ml of water and stir well, then slowly pour into 100ml of boiling water, stirring while adding, continue boiling for 2min, cool, and pour off the upper clear layer. This solution should be prepared freshly before use.

[0125] 0.4% sodium sulfide solution calibration: accurately measure 12.5ml of 0.4% sodium sulfide solution, add 4ml of hydrochloric acid, accurately add 12.5ml of iodine titrant (0.05mol / L), shake well; titrate with sodium thiosulfate titrant (0.1mol / L) until yellow, add 0.5ml of starch indicator solution, continue titrating until blue disappears, and make blank correction. Each 1ml of sodium thiosulfate titrant (0.1mol / L) is equivalent to 68.16μg / ml of hydrogen sulfide.

[0126] Preparation of reference solution: accurately measure an appropriate amount of 0.4% sodium sulfide solution, dilute with water to make solutions containing about 0.3μg, 0.5μg, 1.0μg, 1.5, 2.0μg, and 4.0μg of hydrogen sulfide per 1ml, accurately measure 1.0ml of each, place in a 20ml headspace bottle, add 0.2ml of 0.5mol / L sulfuric acid, and seal. This is used as reference solution 1 to 6.

[0127] The chromatographic conditions are as follows: column temperature is 40°C; column flow rate is 2.0 ml / min; injection port temperature is 180°C; split ratio is 2:1, detector is FPD detector; detector temperature is 200°C; headspace equilibrium temperature is 80°C; headspace equilibrium time is 30 min.

[0128] The reference solution and the test solution were tested under the above chromatographic conditions and calculated according to the following formula

[0129] 0.4% sodium sulfide solution calibration calculation formula:

[0130]

[0131] Where: C RX : Concentration of reference substance stock solution, g / ml;

[0132] V0: blank consumption of sodium thiosulfate titrant volume, ml;

[0133] C: concentration of sodium thiosulfate titrant, mol / L;

[0134] V: volume of sodium thiosulfate titration solution consumed by the reference substance stock solution, ml;

[0135] 0.1: Theoretical concentration of sodium thiosulfate titrant, mol / L;

[0136] Hydrogen sulfide content calculation formula:

[0137] 1 in log 10 C is the ordinate, log 10 A is the horizontal axis, and the linear regression equation is calculated.

[0138] Linear regression equation: log 10 C=K×log 10 A+b

[0139] Where: C: concentration of reference solution, μg / ml;

[0140] A: peak area of ​​reference solution;

[0141] 2 Calculate the content of hydrogen sulfide in the test solution according to the linear equation.

[0142]

[0143] Where: A S : The peak area of ​​hydrogen sulfide in the test solution;

[0144] C S : Concentration of acetylcysteine ​​in the test solution, g / ml;

[0145] K: slope of the linear regression equation;

[0146] b: intercept of the linear regression equation;

[0147] The hydrogen sulfide content in the acetylcysteine ​​solution measured in this example is 82 ppm.

[0148] Example 5

[0149] A method for determining the hydrogen sulfide content in an acetylcysteine ​​solution is achieved by the following steps:

[0150] Preparation of sample solution: Accurately measure acetylcysteine ​​injection and use water to make a solution containing about 5 mg of acetylcysteine ​​per 1 ml. Accurately measure 1.0 ml and place it in a 20 ml headspace bottle. Add 0.6 ml of 0.5 mol / L sulfuric acid and seal it as the test solution.

[0151] Starch indicator solution: accurately weigh 0.5g of soluble starch, add 5ml of water and stir well, then slowly pour into 100ml of boiling water, stirring while adding, continue boiling for 2min, cool, and pour off the upper clear layer. This solution should be prepared freshly before use.

[0152] 0.4% sodium sulfide solution calibration: accurately measure 12.5ml of 0.4% sodium sulfide solution, add 4ml of hydrochloric acid, accurately add 12.5ml of iodine titrant (0.05mol / L), shake well; titrate with sodium thiosulfate titrant (0.1mol / L) until yellow, add 0.5ml of starch indicator solution, continue titrating until blue disappears, and make blank correction. Each 1ml of sodium thiosulfate titrant (0.1mol / L) is equivalent to 68.16μg / ml of hydrogen sulfide.

[0153] Preparation of reference solution: accurately measure an appropriate amount of 0.4% sodium sulfide solution, dilute with water to make solutions containing about 0.3μg, 0.5μg, 1.0μg, 1.5, 2.0μg, and 4.0μg of hydrogen sulfide per 1ml, accurately measure 1.0ml of each, place in a 20ml headspace bottle, add 0.6ml of 0.5mol / L sulfuric acid, and seal. This is used as reference solution 1 to 6.

[0154] The chromatographic conditions are as follows: column temperature is 40°C; column flow rate is 1.0 ml / min; injection port temperature is 180°C; split ratio is 3:1, detector is FPD detector; detector temperature is 200°C; headspace equilibrium temperature is 80°C; headspace equilibrium time is 30 min.

[0155] The reference solution and the test solution were tested under the above chromatographic conditions and calculated according to the following formula

[0156] 0.4% sodium sulfide solution calibration calculation formula:

[0157]

[0158] Where: C RX : Concentration of reference substance stock solution, g / ml;

[0159] V0: blank consumption of sodium thiosulfate titrant volume, ml;

[0160] C: concentration of sodium thiosulfate titrant, mol / L;

[0161] V: volume of sodium thiosulfate titration solution consumed by the reference substance stock solution, ml;

[0162] 0.1: Theoretical concentration of sodium thiosulfate titrant, mol / L;

[0163] Hydrogen sulfide content calculation formula:

[0164] 1 in log 10 C is the ordinate, log 10 A is the horizontal axis, and the linear regression equation is calculated.

[0165] Linear regression equation: log 10C=K×log 10 A+b

[0166] Where: C: concentration of reference solution, μg / ml;

[0167] A: peak area of ​​reference solution;

[0168] 2 Calculate the content of hydrogen sulfide in the test solution according to the linear equation.

[0169]

[0170] Where: A S : The peak area of ​​hydrogen sulfide in the test solution;

[0171] C S : Concentration of acetylcysteine ​​in the test solution, g / ml;

[0172] K: slope of the linear regression equation;

[0173] b: intercept of the linear regression equation;

[0174] The hydrogen sulfide content in the acetylcysteine ​​solution measured in this example is 88 ppm.

[0175] The results of the determination of the hydrogen sulfide content in the acetylcysteine ​​solution in Examples 1-5 show that the method can accurately and quickly determine the content of hydrogen sulfide in the acetylcysteine ​​solution.

[0176] After the detection method of the present invention is determined, the experiment to verify its determination effect is as follows:

[0177] Experiment 1: Stability of solution

[0178] Weigh 10 mg of sodium metabisulfite, accurately weigh it, put it into a 20 ml volumetric flask, dissolve it with the mobile phase in Example 1 and dilute it to the mark, shake it well, and use it as the reference solution.

[0179] The experiment was carried out precisely according to the chromatographic conditions of Example 1 at 0 hours, 8 hours, 12 hours, 18 hours, 24 hours, 31 hours and 38 hours, and the chromatogram was recorded. The results are shown in Table 1 below.

[0180] Table 1 Solution stability results

[0181] name 0h 8h 12h 18h 24h 31h 38h Peak area 172635 173926 173394 169708 171726 163726 158726 Rate of change (%) — 0.7 0.4 1.7 0.5 5.2 8.1

[0182] Experiment 2: Preparation of standard curve

[0183] Chromatographic conditions: the same as those in Example 1.

[0184] Accurately measure an appropriate amount of 0.4% sodium sulfide solution, dilute with water to make a solution containing about 0.3μg to 0.4μg of hydrogen sulfide per 1ml, accurately measure 1.0ml respectively, place in a 20ml headspace bottle, add 0.4ml of 0.5mol / L sulfuric acid, and seal. As linear solutions 1 to 7, as shown in Table 2 below.

[0185] Table 2

[0186]

[0187] Log 10 (concentration) is the ordinate, log 10 (peak area) is the abscissa, and the linear regression equation is calculated.

[0188] See also Figure 2 The hydrogen sulfide solution is linear in the range of 0.2μg / ml to 4.3μg / ml. The linear regression equation is: y=0.5149x-3.1216, the correlation coefficient r=0.9981, and when the signal-to-noise ratio is 12:1, the quantitative limit of hydrogen sulfide is

[0189] 0.21μg / ml.

[0190] The results show that under the chromatographic conditions of Example 1, the linearity is good and the limit of quantification can fully meet the requirements for accurate determination of hydrogen sulfide.

[0191] Experiment 3: Recovery rate test

[0192] Chromatographic conditions: The chromatographic conditions described in Example 1 were used.

[0193] Add a certain amount of reference preparation solution (take a certain amount of 0.4% sodium sulfide solution and dilute it with water to make a solution containing about 20μg per 1ml) to the negative test solution (a solution without acetylcysteine ​​prepared according to the prescription), then measure the amount of hydrogen sulfide in the solution and calculate the recovery rate. The concentrations examined were 50ppm, 100ppm, 200ppm, and 400ppm.

[0194] Solvent: Water.

[0195] 0.5mol / L sulfuric acid: Accurately measure 2.7ml of sulfuric acid and slowly add it into a 100ml volumetric flask containing an appropriate amount of solvent. Dilute to the scale with solvent and shake well.

[0196] Negative test solution (without acetylcysteine): prepare acetylcysteine ​​solution for inhalation (without acetylcysteine) according to the prescription equivalent.

[0197] Reference substance stock solution: 0.4% sodium sulfide solution.

[0198] Starch indicator solution: accurately weigh 0.5g of soluble starch, add 5ml of water and stir well, then slowly pour into 100ml of boiling water, stirring while adding, continue boiling for 2min, cool, and pour off the upper clear layer. This solution should be prepared freshly before use.

[0199] Calibration of reference stock solution: accurately measure 12.5 ml of reference stock solution, add 4 ml of hydrochloric acid, accurately add 12.5 ml of iodine titrant (0.05 mol / L), shake well; titrate with sodium thiosulfate titrant (0.1 mol / L) until yellow, add 0.5 ml of starch indicator solution, continue titrating until the blue color disappears, and make a blank correction.

[0200] Recovery stock solution: Accurately measure an appropriate amount of reference stock solution and dilute with water to make a solution containing approximately 20 μg per 1 ml.

[0201] Reference solution: Accurately measure 0.3ml, 0.5ml, 1.0ml, 1.5ml, 2.0ml, and 4.0ml of the recovery stock solution, place them in different 20ml volumetric bottles, dilute to the mark with solvent, and shake well; accurately measure 1.0ml, place them in 20ml headspace bottles, add 0.4ml of 0.5mol / L sulfuric acid, and seal. This is used as reference solution 1 to 6.

[0202] 50% recovery solution: accurately measure 1.0 ml of negative test solution, place it in a 20 ml volumetric flask, accurately add 0.5 ml of spiked stock solution, dilute to scale with solvent, shake well; accurately measure 1.0 ml, place it in a 20 ml headspace bottle, add 0.4 ml of 0.5 mol / L sulfuric acid, and seal. Prepare 3 copies in parallel with the same method.

[0203] 100% recovery solution: accurately measure 1.0 ml of negative test solution, place it in a 20 ml volumetric flask, accurately add 1.0 ml of spiked stock solution, dilute to scale with solvent, shake well; accurately measure 1.0 ml, place it in a 20 ml headspace bottle, add 0.4 ml of 0.5 mol / L sulfuric acid, and seal. Prepare 3 copies in parallel with the same method.

[0204] 200% recovery solution: accurately measure 1.0 ml of negative test solution, place it in a 20 ml volumetric flask, accurately add 2.0 ml of spiked stock solution, dilute to scale with solvent, shake well; accurately measure 1.0 ml, place it in a 20 ml headspace bottle, add 0.4 ml of 0.5 mol / L sulfuric acid, and seal. Prepare 3 copies in parallel with the same method.

[0205] 400% recovery solution: accurately measure 1.0ml of negative test solution, place it in a 20ml volumetric flask, accurately add 4.0ml of spiked stock solution, dilute to scale with solvent, and shake well; accurately measure 1.0ml, place it in a 20ml headspace bottle, add 0.4ml of 0.5mol / L sulfuric acid, and seal. Prepare 3 copies in parallel with the same method. Inject the above reference solution and recovery solution into the gas phase detection, record the chromatogram, and calculate the recovery. The recovery rate is between 83.23% and 107.84%. The results are shown in Table 3 below.

[0206] Table 3 Sample recovery determination results

[0207]

[0208] The results showed that the average recovery rate was 96.1% and the RSD was 9.6%, indicating that the method had good recovery rate and high accuracy.

[0209] Experiment 4: Repeatability test

[0210] Chromatographic conditions: The chromatographic conditions described in Example 1 were used.

[0211] Accurately measure 1.0 ml of acetylcysteine ​​injection, place in a 20 ml volumetric bottle, dilute to the mark with solvent, shake well, accurately measure 1.0 ml, place in a 20 ml headspace bottle, add 0.4 ml of 0.5 mol / L sulfuric acid, and seal. Prepare 6 portions in parallel with the same method. Accurately measure an appropriate amount of 0.4% sodium sulfide solution, dilute with water to make solutions containing approximately 0.3 μg, 0.5 μg, 1.0 μg, 1.5, 2.0 μg, and 4.0 μg per ml, accurately measure 1.0 ml respectively, place in a 20 ml headspace bottle, add 0.4 ml of 0.5 mol / L sulfuric acid, and seal. Use as reference solutions 1 to 6.

[0212] The test solution and the reference solution were tested according to the chromatographic conditions of the present invention, and the chromatograms were recorded. The results are shown in Table 4 below.

[0213] Table 4 Sample repeatability test results

[0214] Number of measurements 1 2 3 4 5 6 RSD(%) Content (ppm) 89.12 64.71 82.60 82.52 76.92 90.36 11.58

[0215] The results showed that the RSD of the repeatability test was 11.58%, which was less than 30%, and the repeatability of the method was good. The method had strong specificity, high sensitivity and good precision, and could accurately and quickly determine the content of hydrogen sulfide in acetylcysteine ​​injection.

[0216] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0217] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A method for detecting hydrogen sulfide content in acetylcysteine ​​solution by gas chromatography, characterized in that, A capillary column with polyethylene glycol 20M as the stationary liquid; a column temperature of 30°C to 50°C; a chromatographic column flow rate of 1.0ml / min to 2.0ml / min; an injection port temperature of 170°C to 190°C; and a split ratio of 1 to 5:

1.

2. A method for detecting hydrogen sulfide content in an acetylcysteine ​​solution by gas chromatography as claimed in claim 1, characterized in that: The detector is FPD; the detector temperature is 190°C to 210°C; the headspace equilibrium temperature is 70°C to 90°C; and the headspace equilibrium time is 15min to 45min.

3. A method for detecting hydrogen sulfide content in an acetylcysteine ​​solution by gas chromatography as claimed in claim 2, characterized in that: The method also includes preparing a sodium sulfide solution with a concentration of 0 μg / ml to 4 μg / ml, measuring 1.0 ml of each sodium sulfide solution of different concentrations, placing them in 20 ml headspace bottles, and adding 0.2 ml to 0.6 ml of a 0.5 mol / L sulfuric acid solution as a reference solution.

4. A method for detecting hydrogen sulfide content in an acetylcysteine ​​solution by gas chromatography as claimed in claim 3, characterized in that: The method also includes measuring 1.0 ml of the acetylcysteine ​​sample solution, placing it in a 20 ml headspace bottle, adding 0.2 ml to 0.6 ml of 0.5 mol / L sulfuric acid, and sealing it as the test solution.

5. A method for detecting hydrogen sulfide content in an acetylcysteine ​​solution by gas chromatography as claimed in claim 1, characterized in that: The capillary column has a membrane thickness of 0.25 μm to 2 μm, a column length of 30 m to 60 m, and an inner diameter of 0.25 mm to 0.53 mm.

6. A method for detecting hydrogen sulfide content in an acetylcysteine ​​solution by gas chromatography as claimed in claim 4, characterized in that: The chromatographic conditions were as follows: capillary column temperature was 40°C; column flow rate was 1.5 ml / min; injection port temperature was 180°C; split ratio was 2:1; detector temperature was 200°C; headspace equilibrium temperature was 80°C; headspace equilibrium time was 30 min; Sodium sulfide solutions with concentrations of 0.3μg / ml, 0.5μg / ml, 1.0μg / ml, 1.5μg / ml, 2.0μg / ml, and 4.0μg / ml were prepared respectively, 1.0ml was measured and placed in a 20ml headspace bottle, 0.4ml of 0.5mol / L sulfuric acid was added, and the solution was sealed as a reference solution; Measure 1.0 ml of acetylcysteine ​​sample solution, place it in a 20 ml headspace bottle, add 0.4 ml of 0.5 mol / L sulfuric acid, and seal it as the test solution.

7. A method for detecting hydrogen sulfide content in an acetylcysteine ​​solution by gas chromatography as claimed in claim 6, characterized in that: Hydrogen sulfide content calculation formula:

1. Log 10 C is the ordinate, log 10 A is the horizontal axis, and the linear regression equation is calculated: Linear regression equation: log 10 C=K×log 10 A+b; Where: C: concentration of reference solution, μg / ml; A: peak area of ​​reference solution; 2. Calculate the content of hydrogen sulfide in the test solution according to the linear equation: Where: A S : The peak area of ​​hydrogen sulfide in the test solution; C S : Concentration of acetylcysteine ​​in the test solution, g / ml; K: slope of the linear regression equation; b: intercept of the linear regression equation.

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