01 Solution Summary
Drinking water samples are placed in sealed headspace vials to establish gas-liquid or gas-solid equilibrium; the gas phase in the vial is taken into the GC to determine trichloromethane, carbon tetrachloride, and volatile halogenated hydrocarbons covered by the method. This page serves as a topic entry point for volatile halogenated hydrocarbons in drinking water, focusing on the target analyte scope, headspace sampling boundaries, ECD response, and the selection relationship among different sub-solutions. Quantitation and quality control use the following arrangement: calibration relationships are established around trichloromethane, carbon tetrachloride, and volatile halogenated hydrocarbons covered by the method using reference materials matched to the detection channel; the qualitative basis, quantitation mode, and result units are subject to the applicable method; blanks, calibration checks, parallel samples, and QC samples form batch quality control. Analytical batches also include blanks, calibration checks, and applicable QC samples.
02 Standards and Method Basis
Chinese standard: English standard titles on this page are descriptive translations. The cited Chinese text is authoritative.
Method basis: application method. The laboratory may enter the name and version of the adopted formal method into the project file.
03 Samples and Analytes
The specific samples areDrinking water samples, and the analytes areChloroform, carbon tetrachloride, and the volatile halogenated hydrocarbons covered by the method. Pretreatment, injection, and detection configurations are determined according to the sample state, target concentration, and the formal method adopted.
04 Method Principle
Volatile components in a sealed headspace vial reach reproducible partitioning between the sample phase and the gas phase; the automatic headspace system samples from the gas phase and transfers it to the GC.
This route is centered on the equilibrium and gas-phase transfer of volatile components, with ECD as the detection unit.
05 Sample Collection and Pretreatment
Weigh or measure a drinking water sample into a clean headspace vial, add matrix adjustment components according to the official method used, and seal immediately. Sample vials, blank vials, and standard vials use a consistent equilibration and injection procedure.
After sampling, drinking water samples should remain sealed and headspace and transfer should be minimized; the laboratory then selects headspace vial conditions, matrix adjustment, and calibration approach based on the target halogenated hydrocarbon range.
06 Separation and Detection
The headspace gas phase enters the GC through the transfer path, the chromatographic column separates trichloromethane, carbon tetrachloride, and volatile halogenated hydrocarbons covered by the method, and the ECD acquires the response.
ECD has a selective response to halogenated compounds, but whether specific target analytes can be separated and quantified simultaneously still needs to be jointly confirmed by the chromatographic column, headspace program, and official method.
07 Instrument System Configuration
| Module | Configuration | Role in This Solution |
|---|---|---|
| Sample container | Sealed headspace vial and sealing components | Establish a closed equilibrium system |
| Headspace sampler | Thermostatting, shaking, and gas-phase sampling | Transfer volatile components |
| GC system | GC | Complete the separation of volatile components |
| Detection Unit | ECD | Acquire target analyte responses |
08 Huishi Instruments Compatible Products
GC-460 gas chromatograph
- Product name
- GC-460 gas chromatograph
- Model
- GC-460
- Brand
- Huishi Instruments
- Manufacturer
- Shanghai Huishi Instrument Equipment Co., Ltd.
- Product category
- Gas chromatograph
- Role of the solution
- It undertakes the tasks of sample injection, separation, detection, and data acquisition in GC analysis.
- Reason for suitability
- GC-460 can be configured with ECD and quantitative headspace gas injection, and is used for the separation and detection of trichloromethane, carbon tetrachloride, and volatile halogenated hydrocarbons covered by the method in drinking water samples.
09 Analysis workflow
10 Qualitative, Quantitative, and Quality Control
Calibration relationships are established around trichloromethane, carbon tetrachloride, and volatile halogenated hydrocarbons covered by the method using reference materials matched to the detection channel; the qualitative basis, quantitation mode, and result units are subject to the applicable method; blanks, calibration checks, parallel samples, and QC samples form batch quality control. Blank headspace vials, parallel vials, calibration checks, and vial-to-vial repeatability are used to monitor the headspace process.
At the topic level, QC focuses on the target analyte list, blank water, headspace vial background, calibration checks, and the sequence arrangement of high- and low-concentration samples.
11 Method and Configuration Selection
- The sample must be suitable for achieving reproducible gas-phase partitioning in a sealed vial.
- The equilibration procedure, vial volume, and sampling mode are kept consistent between calibration and samples.
- First select the specific sub-solution according to the target analyte scope.
- The topic page does not replace the experimental conditions in the specific standard.
- Focus on halogenated target analytes, ECD response characteristics, and the corresponding water sample method, and do not mix it with the GC-MS route of HJ 639-2012.
12 Frequently Asked Questions
Why is headspace-GC used for trichloromethane, carbon tetrachloride, and volatile halogenated hydrocarbons covered by the method?
Headspace-GC matches the physicochemical properties, sample inlet, and detection targets of trichloromethane, carbon tetrachloride, and volatile halogenated hydrocarbons covered by the method; the complete route also covers the treatment, separation, detection, and data quality control of drinking water samples.
What samples is this solution applicable to?
The applicable samples are drinking water samples. When the sample source or matrix changes, the influence of co-existing components on pretreatment, separation, and detection response should be re-evaluated.
What components or indicators are included in the detection targets?
The analytes are chloroform, carbon tetrachloride, and the volatile halogenated hydrocarbons covered by the method; the main text and configuration are both bounded by this analyte scope.
How is quality controlled for an analytical batch?
For each batch of samples, set up method blanks, calibration verification, duplicate samples, or applicable QC samples, and retain records of sample processing, instrument conditions, calibration, and calculations.
How are the sample introduction and detection modules matched in this solution?
Quantitative headspace gas injection is responsible for introducing the treated drinking water sample into the analytical system, and the detection unit is configured according to the response characteristics of trichloromethane, carbon tetrachloride, and volatile halogenated hydrocarbons covered by the method; both must remain consistent with the method used.
Why is headspace vial sealing important?
The sealing state directly affects the partitioning of volatile components between the sample phase and the gas phase and the injection repeatability.
What problems is the topic entry page suitable for solving?
Used to first confirm the sample, target halogenated hydrocarbons, headspace route, and detector boundaries, then proceed to more specific system configuration or target analyte protocols.
13 Related Solutions and Knowledge
Get Configuration and Technical Consultation
Please provide the sample information for the drinking water sample, the concentration ranges of trichloromethane, carbon tetrachloride, and the volatile halogenated hydrocarbons covered by the method, the testing batch size, the method basis, and the existing equipment. Huishi Instruments will use this to prepare a configuration list.
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