automatic headspace samplerThere was an abnormal noise during the sampling process. What may have gone wrong?

This is a convenient and quick sample pretreatment method for gas chromatography. The principle is to put the sample to be tested in a sealed container, and by heating and heating the sample matrix, volatile components are volatilized, so as to achieve gas-liquid (or gas-solid) two-phase equilibrium.

In GC and GC/MS applications, a sample processing platform that integrates a variety of innovative technologies can further improve the productivity, performance and diversity of automatic headspace samplers. In particular, the system's high-precision automatic sampling processing function saves manual operation and downtime, such as traditional operations such as dilution of the winning or reserve solution or addition of derivatives to the internal standard require manual operation and downtime.

Automatic headspace sampler operation steps.

1. Set parameter lofting, set sample, valve box, pipe temperature, 50 degree sample, 130 degree valve box, 140 degree pipe, lofting after the temperature is stable, the following operations are carried out after 30 minutes of balance.

2. Blow and wash before injection. Set the purge pressure of 0.2-0.3Mpa. Press the purge button and turn it off after about 30 seconds.

3. Prepare the sample. First insert the sampling tube into the corresponding bottle, and then tie the injection tube to the chromatography injection port. Observe the number of pressure displays, from small to large. When stable, adjust the carrier gas adjustment knob and add a grid to the pressure display (0.02MPa).

4. Inject samples. Start sampling. When the chromatograph starts sampling, start sampling the chromatograph. Hear a click. Take out the sampling tube after 2s-3s.

5. Pull out the injection tube. When a bang is heard, the injection lamp goes out and the injection tube is pulled out. Adjust the charge gas to zero.

6. Complete this injection after 30 seconds of purging.

Precautions for the use of automatic headspace sampler:

1. The gas used in the headspace is also purified, because the carrier gas entering the headspace enters the GC at the same time.

2. Heating temperature of the top empty bottle. Dosing tube temperature. The transmission line temperature should be from small to large, and the transmission line temperature should be less than or equal to the injection port temperature.

3. When in use, the total flow rate of GC gas should be the top gas flow plus the GC gas flow rate, and attention should be paid when calculating the split ratio. Can be measured with a flow meter.

4. The sample filling time of the quantitative tube should be sufficient, the balance time of the quantitative tube should not be too long, and the injection time should be long enough.

5. If the pressure regulation is manual, after the construction method is completed, the sample pressure and air pressure value should be recorded to avoid pressure changes caused by valve state changes.

Common faults of automatic headspace sampler and their solutions.

1. When the display screen shows 555 or 000, the manufacturer can replace the temperature measuring resistor when all temperature control components are not heated, the sampling program does not work, and the blowing button does not respond;

2. The air conditioner temperature is adjusted to 15 ℃ or the manufacturer, without heating, the heater of the corresponding parts is burnt out or the ambient temperature is too low;

3. After headspace sampling, the chromatograph has no peak value (the chromatograph works normally), and four faults can occur: a. the headspace sampling needle is blocked; B. the injection needle is blocked; C. the outlet pressure of the headspace sampling needle is less than the pressure of the column head of the chromatograph; D. the headspace sampling valve is directly replaced with the needle in the spare part, or the needle is burned by pressing the purge key with a lighter.