Soil cyanide determination apparatus based on gas chromatography

Abstract

The utility model belongs to soil detection technical field especially for soil cyanide determination device based on gas chromatography, including including preprocessing unit, gas chromatography detection unit and automation control unit, preprocessing unit includes ultrasonic extraction module, automatic distillation module and derivatization module, gas chromatography detection unit includes headspace sampler, chromatographic column and detector, automation control unit includes microprocessor and data processing module, still include the derivatization device for derivatization module in preprocessing unit, the utility model, adopt ultrasonic extraction and automatic distillation combination, shorten the pretreatment time, shake the reactor ware in the derivatization process simultaneously, make the reactant fast mixing reaction, promote the reaction speed and efficiency, and the detection sensitivity is promoted to chloramine T derivatization technology, and the sample processing is from data output and all is by microprocessor control, reduces the human error, promotes the accuracy of detection, and the speed is fast, the efficiency is high, and the convenient use.

Description

Technical Field

[0001] This utility model relates to the field of soil testing technology, specifically to a soil cyanide determination device based on gas chromatography. Background Technology

[0002] Cyanide is a highly toxic substance widely found in industrially contaminated soils. Currently, methods for determining cyanide in soil mainly include spectrophotometry, ion chromatography, and gas chromatography. Among these, gas chromatography has become one of the mainstream methods due to its high sensitivity and selectivity. However, existing gas chromatography devices for determining soil cyanide have the following shortcomings: low pretreatment efficiency: traditional distillation or extraction methods are time-consuming and easily affected by impurities; insufficient automation: numerous manual operation steps lead to significant errors; limited detection sensitivity: the detection effect for trace amounts of cyanide is not ideal.

[0003] For example, Chinese patent CN202022897634.5 discloses a device for detecting cyanide and fluoride in soil, but its pretreatment unit does not integrate efficient distillation and derivatization functions and lacks an automated control module. At the same time, the cyanide derivatization reaction rate is slow during soil extraction, which affects the detection efficiency. Utility Model Content

[0004] (a) Technical problems to be solved

[0005] To address the shortcomings of existing technologies, this invention provides a soil cyanide determination device based on gas chromatography. By optimizing the pretreatment process, integrating an automated control module, and improving detection technology, it enhances detection efficiency and accuracy. This solves the problems of the pretreatment unit lacking efficient distillation and derivatization functions and an automated control module, as well as the slow cyanide derivatization reaction rate during soil extraction, which affects detection efficiency.

[0006] (II) Technical Solution

[0007] To achieve the above objectives, this utility model specifically adopts the following technical solution:

[0008] A soil cyanide determination device based on gas chromatography includes a pretreatment unit, a gas chromatography detection unit, and an automated control unit.

[0009] The preprocessing unit includes:

[0010] Ultrasonic extraction module: It uses an ultrasonic generator with an ultrasonic frequency of 20-80kHz and an extraction time of 10-20min to break up and extract soil samples, thereby accelerating the release of cyanide.

[0011] Automatic distillation module: integrates a gradient temperature control heating device with a heating temperature of 50-150℃ and an anti-backflow condensation system to convert cyanide into hydrogen cyanide gas;

[0012] Derivatization module: Hydrogen cyanide is derivatized to cyanogen chloride using chloramine T solution at a concentration of 0.1-0.5 g / L and a reaction temperature of 45±0.2℃, thereby improving detection sensitivity;

[0013] The gas chromatography detection unit:

[0014] Headspace sampler: Equilibrium temperature 55-60℃, equilibrium time 20-30min, using DB-624 capillary column with dimensions of 30m×0.25mm×0.25μm, and programmed temperature ramp rate of 10-30℃ / min for separation;

[0015] Detector: One of an electron capture detector or a flame ionization detector, with a detection limit as low as 0.05 μg / g;

[0016] The automated control unit:

[0017] Microprocessor: Integrates temperature and pressure sensors to monitor distillation temperature and gas flow rate in real time, with a control accuracy of ±0.2℃;

[0018] Data processing module: Based on a reverse control chromatography workstation, it automatically generates standard curves and calculates cyanide content; the data can be integrated with a LIMS system.

[0019] It also includes a diffractor for the derivatization module in the pretreatment unit, the diffractor being rotatably connected to the support frame and driven by a servo motor, and a reagent adder being provided directly above the diffractor;

[0020] It also includes an exhaust gas treatment unit, which uses activated carbon adsorption devices to treat waste gas.

[0021] Furthermore, the derivatizer includes a shell and a reactor dish, a constant temperature heater is arranged between the shell and the reactor dish, and a connecting shaft provided on the side wall of the shell is rotatably connected to the support frame through a bearing, one of the connecting shafts being drivenly connected to the output shaft of a servo motor, and the servo motor being fixedly connected to the support frame by bolts;

[0022] The reagent dispenser includes an infusion tube connected to a reagent delivery device. The infusion tube is connected to a drip head via a branch tube. The branch tube and the drip head are arranged in a one-to-one correspondence and are distributed at equal intervals on the infusion tube.

[0023] (III) Beneficial Effects

[0024] Compared with the prior art, this utility model provides a soil cyanide determination device based on gas chromatography, which has the following beneficial effects:

[0025] This invention combines ultrasonic extraction with automated distillation, shortening the pretreatment time. Simultaneously, the reactor vessel is shaken during derivatization to rapidly mix the reactants, improving reaction speed and efficiency. The chloramine-T derivatization technology enhances detection sensitivity. From sample processing to data output, everything is controlled by a microprocessor, reducing human error and improving detection accuracy. It is fast, efficient, and easy to use. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of this utility model;

[0027] Figure 2 This is a schematic diagram of the diffractor in this utility model;

[0028] Figure 3 This is a schematic diagram of the reagent adder in this utility model.

[0029] In the diagram: 1. Derivatizer; 101. Outer shell; 102. Connecting shaft; 103. Reactor dish; 104. Constant temperature heater; 2. Support frame; 3. Servo motor; 4. Reagent adder; 401. Infusion tube; 402. Branch tube; 403. Dropper. Detailed Implementation

[0030] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0031] Example

[0032] like Figure 1 , Figure 2 and Figure 3 As shown, one embodiment of this utility model includes a pretreatment unit, a gas chromatography detection unit, and an automated control unit;

[0033] The preprocessing unit includes:

[0034] Ultrasonic extraction module: It uses an ultrasonic generator with an ultrasonic frequency of 20-80kHz and an extraction time of 10-20min to break up and extract soil samples, thereby accelerating the release of cyanide.

[0035] Automatic distillation module: integrates a gradient temperature control heating device with a heating temperature of 50-150℃ and an anti-backflow condensation system to convert cyanide into hydrogen cyanide gas;

[0036] Among them, the combination of ultrasonic extraction and automatic distillation shortens the pretreatment time and greatly improves efficiency.

[0037] Derivatization module: Hydrogen cyanide is derivatized to cyanogen chloride using chloramine T solution at a concentration of 0.1-0.5 g / L and a reaction temperature of 45±0.2℃, thereby improving detection sensitivity;

[0038] Among them, the chloramine T derivatization technology improves detection sensitivity and has a high recovery rate;

[0039] Gas chromatography detection unit:

[0040] Headspace sampler: Equilibrium temperature 55-60℃, equilibrium time 20-30min, using DB-624 capillary column with dimensions of 30m×0.25mm×0.25μm, and programmed temperature ramp rate of 10-30℃ / min for separation;

[0041] Detector: One of an electron capture detector or a flame ionization detector, with a detection limit as low as 0.05 μg / g;

[0042] Automation control unit:

[0043] Microprocessor: Integrates temperature and pressure sensors to monitor distillation temperature and gas flow rate in real time, with a control accuracy of ±0.2℃;

[0044] Data processing module: Based on a reverse control chromatography workstation, it automatically generates standard curves and calculates cyanide content; the data can be integrated with a LIMS system.

[0045] The entire process, from sample processing to data output, is controlled by a microprocessor, reducing human error.

[0046] It also includes an exhaust gas treatment unit, which uses activated carbon adsorption devices to treat waste gas and prevent cyanide leakage;

[0047] It also includes a diffractor 1 for the derivatization module in the pretreatment unit. The diffractor 1 is rotatably connected to the support frame 2 and driven by the servo motor 3. A reagent adder 4 is set directly above the diffractor 1 to facilitate the conversion of cyanide into hydrogen cyanide gas during soil sample processing in the detection process. After the gas is condensed into liquid, it is added to the diffractor 1. Then, chloramine T solution is added to derivatize hydrogen cyanide into cyanogen chloride, thereby improving the sensitivity of subsequent detection. At the same time, during the addition of chloramine T solution, the servo motor 3 drives the diffractor 1 to reciprocate on the support frame 2, so that the hydrogen cyanide gas condensate in the diffractor 1 is quickly mixed with the chloramine T solution, thereby improving the reaction speed and efficiency.

[0048] Furthermore, the diffractor 1 includes a shell 101 and a reactor dish 103. A constant temperature heater 104 is arranged between the shell 101 and the reactor dish 103 to heat the reactants in the reactor dish 103 during the reaction process, thereby promoting the rapid reaction. A connecting shaft 102 provided on the side wall of the shell 101 is rotatably connected to the support frame 2 through a bearing. One of the connecting shafts 102 is connected to the output shaft of the servo motor 3. The servo motor 3 is fixedly connected to the support frame 2 by bolts, which facilitates the stable installation of the diffractor 1 on the support frame 2. At the same time, the servo motor 3 drives the diffractor 1 to smoothly reciprocate on the support frame 2.

[0049] The reagent adder 4 includes an infusion tube 401 connected to the reagent delivery equipment. The infusion tube 401 is connected to the dropper 403 through a branch tube 402. The branch tube 402 and the dropper 403 are arranged one-to-one and distributed at equal intervals on the infusion tube 401, which facilitates the rapid distribution of chloramine T solution to each dropper 403, and then adds it to the reaction vessel 103 to ensure smooth derivatization.

[0050] The specific process of derivation is as follows:

[0051] Reagent preparation:

[0052] Chloramine T solution: Weigh 0.1-0.5g chloramine T, dissolve it in 100mL of pure water, and prepare a 0.1-0.5% (m / v) solution;

[0053] Isonicotinic acid-pyrazolone solution: Dissolve 1.5g of isonicotinic acid and 0.25g of pyrazolone in 100mL of sodium hydroxide solution with a concentration of 0.5mol / L, and store in the dark.

[0054] Reaction process:

[0055] Step 1: The distilled hydrogen cyanide gas is introduced into the derivatization module, and 1-2 mL of chloramine T solution with a concentration of 0.1-0.5% is added. The solution is adjusted with phosphate buffer at pH 6.8-7.5 and reacted at 45±0.2℃ for 5-10 minutes to generate cyanide chloride.

[0056] Add 2-3 mL of isonicotinic acid-pyrazolone solution and continue the reaction at 40-45℃ for 15-20 minutes to generate a blue dye with a maximum absorption wavelength of 638 nm.

[0057] The specific conditions for controlling the reaction process are as follows:

[0058] Temperature control: A constant temperature heater is used to maintain the reaction temperature, with a temperature control accuracy of ±0.2℃, to ensure stable derivatization efficiency;

[0059] Time control: Precise timing via microprocessor, with a reaction time error of ≤ ±0.5 minutes;

[0060] pH adjustment: Use an automatic dispensing system to add phosphate buffer solution with a pH of 7.0 to ensure the reaction is carried out under weakly alkaline conditions.

[0061] In order to eliminate interference, adding an appropriate amount of sodium arsenite can eliminate sulfide interference, and adding EDTA can mask metal ions such as Cu²⁺ and Fe³⁺.

[0062] By controlling temperature and pH in steps, efficient derivatization of cyanide is achieved, which is more sensitive than traditional methods. The derivatization module is seamlessly integrated with the distillation system, avoiding losses in intermediate transfer steps and achieving a high recovery rate. Temperature sensors and timers ensure the consistency of reaction conditions and reduce human error.

[0063] The specific testing steps are as follows:

[0064] Sample processing:

[0065] Weigh 5g of soil sample, add 10mL of phosphoric acid solution (pH<8), and treat in an ultrasonic extraction module for 10-20min.

[0066] The extract was transferred to an automatic distillation module and distilled at 100°C for 30 minutes. The hydrogen cyanide gas was condensed and then entered the derivatization module.

[0067] Derivatization reaction:

[0068] Add 0.1 mL of chloramine T solution (concentration 20 g / L) to the derivatization module and react at 45℃±0.2℃ for 10 min to generate cyanogen chloride.

[0069] Gas chromatography analysis:

[0070] Headspace sampler parameters: equilibrium temperature 60℃, equilibrium time 30min;

[0071] Column temperature program: initial temperature 40℃, hold for 1 min, increase to 100℃ at 10℃ / min, then increase to 200℃ at 30℃ / min, hold for 0.1 min;

[0072] The detector temperature was 300℃, and the cyanide content was calculated using the external standard method to obtain specific data on the cyanide content in the soil.

[0073] Finally, it should be noted that the above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A soil cyanide determination device based on gas chromatography, comprising a pretreatment unit, a gas chromatography detection unit, and an automated control unit, characterized in that: The pretreatment unit includes an ultrasonic extraction module, an automatic distillation module, and a derivatization module; The gas chromatography detection unit includes a headspace sampler, a chromatographic column, and a detector; The automated control unit includes a microprocessor and a data processing module; It also includes a diffractor (1) for the derivatization module in the pretreatment unit, the diffractor (1) being rotatably connected to the support frame (2) and driven by the servo motor (3), and a reagent adder (4) is provided directly above the diffractor (1).

2. The soil cyanide determination device based on gas chromatography according to claim 1, characterized in that: The derivatizer (1) includes a shell (101) and a reactor dish (103). A constant temperature heater (104) is arranged between the shell (101) and the reactor dish (103). A connecting shaft (102) provided on the side wall of the shell (101) is rotatably connected to the support frame (2) through a bearing. One of the connecting shafts (102) is connected to the output shaft of a servo motor (3). The servo motor (3) is fixedly connected to the support frame (2) by bolts.

3. The soil cyanide determination device based on gas chromatography according to claim 1, characterized in that: The reagent adder (4) includes an infusion tube (401) connected to the reagent delivery equipment. The infusion tube (401) is connected to the drip head (403) through a branch tube (402). The branch tube (402) and the drip head (403) are arranged one-to-one and distributed at equal intervals on the infusion tube (401).

4. The soil cyanide determination device based on gas chromatography according to claim 1, characterized in that: The ultrasonic extraction module has an ultrasonic frequency of 20-80kHz and an extraction time of 10-20min. The automatic distillation module has a gradient temperature control range of 50-150℃, and the condensation system adopts an anti-backflow design; The derivatization module uses chloramine T solution as the derivatizing reagent at a concentration of 0.1-0.5 g / L and a reaction temperature of 45 ± 0.2℃. The headspace sampler has an equilibrium temperature of 55-60℃ and an equilibrium time of 20-30 min.

5. The soil cyanide determination device based on gas chromatography according to claim 1, characterized in that: The chromatographic column is a DB-624 capillary column, and the programmed temperature rise rate is 10-30℃ / min; The detector is either an electron capture detector or a flame ionization detector.

6. The soil cyanide determination device based on gas chromatography according to claim 1, characterized in that: The microprocessor integrates a temperature sensor and a pressure sensor, with a temperature control accuracy of ±0.2℃; The data processing module supports standard curve generation and LIMS system integration.

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