CN108196005A - Carbon in a kind of organic liquid sample, nitrogen, hydrogen, sulfur content assay method - Google Patents

Abstract

The invention relates to a method for measuring carbon, nitrogen, hydrogen and sulfur contents in organic liquid samples, which relates to a method for measuring carbon, nitrogen, hydrogen and sulfur contents in organic liquid samples. The purpose of the present invention is to solve the problem that the organic liquid sample will produce wetting phenomenon when it is added into the tin cup, thereby causing the test results of C, H, N and S elements in the sample to deviate from the true value. The method is: spread 3~5mm thick quartz wool on the bottom of the tin cup, then put the tin cup on the balance, and adjust the balance to zero; then add the sample, then wrap the tin cup into a block, and enter it on the organic element analyzer Test content. The invention has good reproducibility and can accurately measure the contents of C, H, N and S elements in organic liquid samples. The invention is applied in the technical field of sample analysis.

Description

A method for measuring carbon, nitrogen, hydrogen and sulfur content in organic liquid samples

technical field

The invention relates to a measuring method, in particular to a measuring method for the content of carbon, nitrogen, hydrogen and sulfur in an organic liquid sample.

Background technique

As a routine instrument in the laboratory, the elemental analyzer can quantitatively analyze and measure the content of C, H, N, S and elements in organic solids, highly volatile and sensitive substances at the same time. Elemental composition and other aspects play an important role. The test principle is that in the CHNS measurement mode, the sample is weighed in a fusible tin capsule or an aluminum capsule and then enters the combustion tube to burn statically in a pure oxygen atmosphere. In the final stage of combustion, a certain amount of dynamic oxygen is introduced to ensure that all organic and inorganic substances are completely combusted. The products after sample combustion pass through specific reagents to form CO ₂ , H ₂ O, SO ₂ , N ₂ and nitrogen oxides, and the reagents remove some interfering substances such as halogen elements and P. Then the gas enters the reduction tube to remove excess oxygen and reduce nitrogen oxides to N ₂ , and then realize gas separation through the purge and trap adsorption column or gas chromatography column, and then enter the thermal conductivity detector.

Wetting is the phenomenon that when a liquid comes into contact with a solid, an adherent layer of the liquid will extend along the surface of the solid. When the contact angle θ is an acute angle, the liquid wets the solid. If θ is zero, the liquid will spread to the entire solid surface. This phenomenon is called "wetting phenomenon". When the organic liquid sample is added to the tin cup, wetting will occur, and the sample will extend from the bottom to the cup mouth along the inner wall of the tin cup. When the tin cup is used to hold the sample with tweezers, the organic liquid sample will overflow and stick to the tweezers , resulting in the loss of sample quality, which leads to the deviation of the test results of C, H, N, S elements in the sample from the true value.

Contents of the invention

The purpose of the present invention is to solve the problem that the organic liquid sample will produce wetting phenomenon when it is added into the tin cup, thereby causing the test results of C, H, N, S elements in the sample to deviate from the true value, and to provide an organic liquid sample Method for determination of carbon, nitrogen, hydrogen and sulfur content in medium.

The assay method of carbon, nitrogen, hydrogen, sulfur content in a kind of organic liquid sample of the present invention, carries out according to the following steps:

1. Tin cup preparation before weighing samples: spread 3-5mm thick quartz wool on the bottom of the tin cup, then put the tin cup on the balance, and adjust the balance to zero;

2. Sample wrapping: remove the tin cup from the balance, then add the organic liquid sample to be tested into the quartz wool at the bottom of the tin cup, then wrap the tin cup into a block, weigh it on the balance, and record the sample weight ;

3. Detection: Put the block-shaped tin cup in step 2 into the organic element analyzer for testing, and obtain the percentage content of carbon, nitrogen, hydrogen, and sulfur elements in the sample.

The beneficial effects of the present invention are:

The invention solves the mass loss of the organic liquid sample added into the tin cup when wrapped due to the wetting phenomenon. Adding quartz wool to the tin cup can well solve the wetting phenomenon of organic liquid samples in the tin cup. The present invention randomly selects three samples, and nine parallel samples of different qualities are measured in parallel. The standard deviations of C, H, N, and S contents in the test results are all around 0.1, indicating that the present invention has good reproducibility and can accurately measure organic C, H, N, S element content in liquid samples. The steps of the invention are simple and easy to operate.

Detailed ways

Specific embodiment one: the assay method of carbon, nitrogen, hydrogen, sulfur content in a kind of organic liquid sample of this embodiment, carry out according to the following steps:

1. Tin cup preparation before weighing samples: spread 3-5mm thick quartz wool on the bottom of the tin cup, then put the tin cup on the balance, and adjust the balance to zero;

2. Sample wrapping: remove the tin cup from the balance, then add the organic liquid sample to be tested into the quartz wool at the bottom of the tin cup, then wrap the tin cup into a block, weigh it on the balance, and record the sample weight ;

3. Detection: Put the block-shaped tin cup in step 2 into the organic element analyzer for testing, and obtain the percentage content of carbon, nitrogen, hydrogen, and sulfur elements in the sample.

The beneficial effects of this embodiment are:

This implementation mode solves the mass loss of the organic liquid sample added to the tin cup when wrapping the sample due to the wetting phenomenon. Adding quartz wool to the tin cup can well solve the wetting phenomenon of organic liquid samples in the tin cup. In this embodiment, three samples are randomly selected, and nine parallel samples of different qualities are measured in parallel. The standard deviations of C, H, N, and S contents in the test results are all around 0.1, which shows that this embodiment has good reproducibility and can accurately Determination of C, H, N, S element content in organic liquid samples. The steps of this embodiment are simple and easy to operate.

Embodiment 2: This embodiment differs from Embodiment 1 in that the size of the tin cup is 5*9mm. Others are the same as the first embodiment.

Embodiment 3: This embodiment is different from Embodiment 1 or Embodiment 2 in that the thickness of the quartz wool is 4mm. Others are the same as those in Embodiment 1 or 2.

Embodiment 4: The difference between this embodiment and one of Embodiments 1 to 3 is that the method of adding samples in step 3 is: use a pipette to take the organic liquid sample to be tested, and insert the tip of the pipette into the tin cup Quartz wool at the bottom. Others are the same as one of the specific embodiments 1 to 3.

Embodiment 5: This embodiment is different from Embodiment 1 to Embodiment 4 in that: wrapping the tin cup into a block refers to closing the upper end of the tin cup with tweezers and then repeatedly folding and bending it to form a square. Others are the same as one of the specific embodiments 1 to 4.

Verify effect of the present invention by following experiment:

Example 1:

A kind of assay method of carbon, nitrogen, hydrogen, sulfur content in organic liquid sample, carry out according to the following steps:

1. Tin cup preparation before weighing samples: spread 4mm thick quartz wool on the bottom of the 5*9mm tin cup, then put the tin cup on the balance, and adjust the balance to zero;

2. Sample wrapping: remove the tin cup from the balance, then use a pipette to take the organic liquid sample to be tested, insert the tip of the pipette into the quartz wool at the bottom of the tin cup, and then wrap the tin cup into a block , weighed on a balance, and record the sample weight;

3. Detection: Put the block-shaped tin cup in step 2 into the organic element analyzer for testing, and obtain the percentage content of carbon, nitrogen, hydrogen, and sulfur elements in the sample.

Randomly select nine parallel samples of different quality from three samples for parallel measurement, to ensure that the weight of parallel samples 1-3 is about 5mg, the weight of parallel samples 4-6 is about 10mg, and the weight of parallel samples 7-9 is about 20mg. The test results are shown in Table 1.

Table 1. Parallel assay results

It can be seen from the measurement results that the standard deviations of C, H, N, and S contents in the parallel samples are all around 0.1, which shows that this embodiment has good reproducibility and can accurately measure the contents of C, H, N, and S elements in organic liquid samples. . The steps of this embodiment are simple and easy to operate.

Claims (5)

1. the assay method of carbon in a kind of organic liquid sample, nitrogen, hydrogen, sulfur content, it is characterised in that this method is according to the following steps It carries out：

First, tin can prepares before claiming sample：The silica wool of 3~5mm thickness is spread in tin can bottom, then tin can is placed on balance, day Heibei provincial opera zero；

2nd, ladle sample：Tin can from balance is removed, then organic liquid sample to be measured is added to the silica wool of tin can bottom In, then tin can is bundled into bulk, it is put on balance and weighs, record sample weight；

3rd, it detects：The block-like tin can that is bundled into of step 2 is entered and is tested on organic element analyzer, obtain carbon in sample, nitrogen, The percentage composition of hydrogen, element sulphur.

2. the assay method of carbon in a kind of organic liquid sample according to claim 1, nitrogen, hydrogen, sulfur content, feature exist In tin can size be 5*9mm.

3. the assay method of carbon in a kind of organic liquid sample according to claim 1, nitrogen, hydrogen, sulfur content, feature exist In silica wool thickness be 4mm.

4. the assay method of carbon in a kind of organic liquid sample according to claim 1, nitrogen, hydrogen, sulfur content, feature exist The method being loaded in step 3 is：Organic liquid sample to be measured is taken with pipettor, pipette tips are inserted into tin can bottom Silica wool in.

5. the assay method of carbon in a kind of organic liquid sample according to claim 1, nitrogen, hydrogen, sulfur content, feature exist In tin can is bundled into, bulk refers to be closed the upper end of tin can with tweezers and then folding bending is built up square.