阅读说明：本技术 利用ea分析海水中颗粒有机碳、颗粒氮的分析方法 (Analysis method for analyzing granular organic carbon and granular nitrogen in seawater by utilizing EA (extractive solution) ) 是由 刘毅 张继红 吴文光 孙科 于 2019-11-18 设计创作，主要内容包括：本发明涉及一种利用EA分析海水中颗粒有机碳、颗粒氮的分析方法,属于海水分析测试技术领域,所述方法从样品的采集、保存、处理、检测的全流程入手,通过改变仪器设置和参数,将加氧量设置为80s,燃烧管温度设置为700℃,实现了检测成本降低30％,通过新的采样方法,稳定空白值数据,提高数据准确度8％,提升工作效率。(The invention relates to an analysis method for analyzing granular organic carbon and granular nitrogen in seawater by EA (absorption EA), belonging to the technical field of seawater analysis and test, starting from the whole process of sample collection, storage, treatment and detection, setting oxygen addition amount to be 80s and setting combustion tube temperature to be 700 ℃ by changing instrument setting and parameters, realizing detection cost reduction by 30%, stabilizing blank value data by a new sampling method, improving data accuracy by 8% and improving working efficiency.)

1. An analysis method for analyzing granular organic carbon and granular nitrogen in seawater by using EA (extractive solution), which is characterized by comprising the following steps of:

a. preparation of materials: taking a GF/F glass fiber filter membrane with the diameter of 25mm, and burning the GF/F glass fiber filter membrane for 5 hours at 450 ℃ in advance for later use;

b. collecting a sample: taking water samples of required stations and layers, filtering the water samples on a ship or after being transported back to a laboratory, filtering the seawater with the volume of 200ml,

after filtering, wrapping a sample filter membrane with tinfoil paper, taking another blank new membrane, sucking the filtered filtrate by a dropper, dropping 3-5 drops on the blank new membrane to moisten the membrane surface, wrapping the filter membrane with tinfoil paper, and storing at-20 ℃ for later use;

c. pretreatment of the sample: taking a membrane sample, acidifying for 30 minutes, taking out the sample, drying in a drying oven at 60 ℃ for 24 hours, and storing in a dryer;

d. coating of the sample: coating the film sample, and preparing the coated sample for measuring the sample on a machine;

e. and (3) determination of a sample: cleaning and debugging the element analyzer according to the operation rules of the instrument to enable the element analyzer to reach a sample testing state; modifying the conventional setting of an instrument, setting the oxygen adding amount to be 80s, setting the temperature of the combustion tube to be 700 ℃, and then starting to test samples;

f. the machine loading sequence of the samples: adding 6-8 acetanilide or sulfanilamide C, N standard substances with stable percentage content, then adding samples, inserting one standard substance into each 10 samples, and starting to operate an instrument for detection after all the samples are placed;

g. data processing of the sample: firstly, observing whether the result of a standard substance is stable, if the standard deviation is lower than 0.2, then the instrument is stable, selecting 6-8 standard substances, carrying out instrument correction, if the correction coefficient range is between 0.9-1.1, then the standard substance can be completely combusted and converted, namely the experimental data is true and credible; then, if sampling is performed according to the method b1, the test data are directly available; if sampling is carried out according to the b2 method, the C, N peak area value measured by each blank film in the software is input into the corresponding sample film C, Nblank column, the instrument can carry out automatic integral calculation, and the obtained new result is the final result; and comparing the measured value of the standard substance inserted into the sample with the true value after the measured value is corrected according to the correction factor, and determining that the data is stable and credible if the error is less than one thousandth.

Technical Field

The invention belongs to the technical field of seawater analysis and test, and particularly relates to an analysis method for analyzing granular organic carbon and granular nitrogen in seawater by using EA (extractive EA).

Technical Field

The element analyzer (Elementar, germany) is the most widely used element analyzer at present, and is a large-scale instrument widely accepted by users, and the percentage content of elements such as C, N and the like can be accurately analyzed by utilizing the principles of dynamic combustion and adsorption analysis, so that the efficiency and the accuracy of analysis work are improved. The element analyzer can also be used as a pretreatment device to be used with a stable isotope mass spectrometer, thereby improving the application range of the element analyzer.

At present, the country is vigorously developing ocean blue economy, emerging fields such as carbon sink fishery and the like are gradually rising, the country pays more and more attention to ocean research, and how to deeply research ocean is particularly important. Granular organic carbon (POC) and granular nitrogen (PN) in the water body reflect the water environment indexes of sea areas, food sources of cultured organisms and the like, and are important parameters for researching the ocean field. However, due to the lack of scientific, complete and normative determination methods, the quality of detected data is low, the cost is high, and the reliability of scientific research results is influenced.

At present, the method for analyzing and testing the element percentage content of granular organic carbon and granular nitrogen in seawater is specified in the 9 th part of GB/T12763.9-2007 ocean investigation code, namely, a glass fiber filter membrane with the diameter of 25mm (pre-burned for 5 hours at 450 ℃) is used for seawater filtration and acidification, and then an element analyzer is used for measurement. However, with the development of science and technology and the development of research fields, the data requirements and the analysis amount of the granular organic carbon and the granular nitrogen are increasing. The detection method standards made in the beginning of this century have been developed in the last decade, and the defects and problems are increasing.

It is mainly shown that, firstly, the pretreatment method is not specified in detail, and corresponding special experimental devices such as an acidification device and a sample coating device are lacked, the deviation of the steps can bring immeasurable influence on the final result of the sample, and the specifications and the use of the pretreatment steps are not elaborated in detail in the national standard.

Secondly, the phenomenon that the internal combustion tube of the element analyzer cracks or explodes can occur at a probability of more than 90% in the analysis process of the sample at present, the main reason is caused by the glass fiber material of the filter membrane, the phenomenon not only increases the use cost of the instrument but also influences the service life of the instrument, and meanwhile, the detection precision of the sample can also be reduced, so that more harm and workload are brought to detection personnel. Because the instrument manufacturer thinks that the lower temperature can cause incomplete combustion of the sample, the working temperature of the instrument is required to be 950 ℃, the explosion of the combustion tube usually occurs in the temperature rise process of the instrument or the sample detection process, and the scraps are cleaned in time after the explosion, so that the experimenter usually needs to operate under the high-temperature condition of 950 ℃, and is extremely dangerous due to carelessness, and toxic chemicals such as lead chromate and the like are filled in the combustion tube, and the combustion tube is completely exposed in the air after the explosion, so that the experimenter is more easily contacted with the experimenter due to more harm to the human body at high temperature. At present, no good solution exists in various maritime colleges and scientific research institutes in China, including foreign instrument company manufacturers, and a relatively universal analysis method for the samples is to use a domestic combustion tube, collect a certain amount of samples and then perform centralized measurement, and use the domestic combustion tube once. Avoid appearing crackle or exploding the phenomenon behind the reuse burner tube and cause bigger influence, this can save about 60% of cost than using former factory's consumptive material, but still more the extravagant cost of conventional sample about 30%, and the domestic consumptive material has impurity to influence the problem of analysis result than imported consumptive material appears quartzy impure more easily.

Finally, the sample collection process is performed. In the ocean carbon library, the content of dissolved organic carbon can reach 4-10 times of that of granular organic carbon, and the influence on the sample is obvious, but the influence on the sample result caused by the attachment of the soluble organic carbon on a filter membrane is not considered in the analysis method of the granular organic carbon and the granular nitrogen specified by the national standard. In the past analysis practice of the content of organic carbon and nitrogen elements in particles, scientific researchers also find that after sampling is carried out according to an international universal blank value sampling method, the blank value of nearly 8% of samples is higher than the sample value, so that the data cannot be used.

Disclosure of Invention

The invention provides an analysis method for analyzing granular organic carbon and granular nitrogen in seawater by EA (atomic emission spectrometry), which aims at solving the problems encountered and existing in the process of analyzing and detecting granular organic carbon and granular nitrogen in seawater by using an element analyzer at present, starts from the whole flow of sample collection, storage, treatment and detection, realizes that the detection cost is reduced by 30% by changing the setting and parameters of an instrument, stabilizes blank value data by a new sampling method, improves the data accuracy by 8%, and improves the working efficiency.

The task of the invention is accomplished in the following way:

an analysis method for analyzing granular organic carbon and granular nitrogen in seawater by using EA comprises the following steps:

a. preparation of materials: taking a GF/F glass fiber filter membrane with the diameter of 25mm, and burning the GF/F glass fiber filter membrane for 5 hours at 450 ℃ in advance for later use;

b. collecting a sample: taking water samples of required stations and layers, filtering the water samples on a ship or after being transported back to a laboratory, filtering the seawater with the volume of 200ml,

after filtering, wrapping a sample filter membrane with tinfoil paper, taking another blank new membrane, sucking the filtered filtrate by a dropper, dropping 3-5 drops on the blank new membrane to moisten the membrane surface, wrapping the filter membrane with tinfoil paper, and storing at-20 ℃ for later use;

c. pretreatment of the sample: taking a membrane sample, acidifying for 30 minutes, taking out the sample, drying in a drying oven at 60 ℃ for 24 hours, and storing in a dryer;

d. coating of the sample: coating the film sample, and preparing the coated sample for measuring the sample on a machine;

e. and (3) determination of a sample: cleaning and debugging the element analyzer according to the operation rules of the instrument to enable the element analyzer to reach a sample testing state; modifying the conventional setting of an instrument, setting the oxygen adding amount to be 80s, setting the temperature of a combustion tube to be 700 ℃, and then starting to test samples;

f. the machine loading sequence of the samples: adding 6-8 acetanilide or sulfanilamide C, N standard substances with stable percentage content, then adding samples, inserting one standard substance into each 10 samples, and starting to operate an instrument for detection after all the samples are placed;

g. data processing of the sample: firstly, observing whether the result of a standard substance is stable, if the standard deviation is lower than 0.2, then the instrument is stable, selecting 6-8 standard substances, carrying out instrument correction, if the correction coefficient range is between 0.9-1.1, then the standard substance can be completely combusted and converted, namely the experimental data is true and credible; inputting the C, N peak area value measured by each blank film in the software into the corresponding sample film C, Nblank column, and automatically integrating and calculating by an instrument to obtain a new result, namely a final result; and comparing the measured value of the standard substance inserted into the sample with the true value after the measured value is corrected according to the correction factor, and determining that the data is stable and credible if the error is less than one thousandth.

Compared with the prior art, the invention has the beneficial effects that:

1. according to the invention, through the blank value calibration method research in the element analysis process, the difference of different sampling methods is verified, and a proper blank value sampling method is determined, so that the accuracy of an analysis result is improved, and influence factors not considered in the national standard of the element analysis method are perfected.

2. The invention provides a concept of subversive changing the temperature setting of the instrument, and experiments confirm that the optimal instrument setting temperature of the sample is-700 ℃, and the temperature can ensure the complete combustion of the sample and can realize the reutilization of the combustion tube. In the experimental verification process, the breakage rate is almost reduced to 0, the service life of the instrument is prolonged, and the detection cost of each sample can be reduced by 30%; the quality of the sample is strictly controlled by the standard substance, so that the reliability of data after the temperature of the instrument is changed is ensured, and the incredible question of manufacturer engineers about changing the temperature data is refuted; meanwhile, the working strength and requirements of similar samples on detection personnel are reduced.

3. The invention combines the device invention related to the apparatus in the past of the applicant, starts from the whole process from sample sampling to analysis, establishes a set of complete seawater particle organic carbon and particle nitrogen element percentage content analysis and detection steps, improves the working efficiency and the data reliability, perfects the problem which is not considered in the national standard and solves the difficulty in the current sample detection process.

Detailed Description

The technical solution of the present invention is further explained by the following examples, but the scope of the present invention is not limited in any way by the examples.