Specialized chromatograph for residual acetaldehyde in PET slices of pharmaceutical packaging preforms

The national standard for bottle grade PET slices specifies acetaldehyde content as the only mandatory indicator, requiring acetaldehyde mass fraction to be less than 1.0 × 10-8. Therefore, acetaldehyde content is the most important control indicator for bottle manufacturers and also the most important quality control indicator for downstream injection molding and blow molding manufacturers.
Huipu Analytical Instrument Manufacturing Hebei Co., Ltd. uses headspace gas chromatography to determine and analyze the acetaldehyde content in bottle grade PET slices. The results showed that the method had good linear relationship, reproducibility, and stability, with a linear correlation coefficient of 0.9995, a detection limit of 0.2 μ g, an average recovery rate of 98.3%, and a relative standard deviation of 2.5%.
In recent years, the demand for PET chips for containers in the world has been increasing at a rate of over 10% per year. China is currently in the high-speed development stage of PET beverage bottles, and the demand for PET bottles for packaging is growing at a double-digit rate every year. Bottle grade PET chips have gradually become the preferred packaging material for people, with the application proportion of PET bottles accounting for 57.4%. In the PET materials used for food packaging, PET slices for beverage bottles account for the largest share, with a share of over 60%. With the increasing attention to food hygiene and safety, there are strict regulations in the national standards for the aldehyde content of bottle grade PET slices. The quality fraction of aldehyde is less than 1 × 10-8 to meet international requirements, which requires enterprises to strictly comply with and exceed the national standards.

Instrument:
1. GC-8890 gas chromatograph, equipped with FID detector and capillary column injection system
2. AHS-20A Fully Automatic Headspace Sampler
3. Specialized quartz capillary chromatography column
4. BF-300E Hydrogen Generator
5. BF-2L air generator

GC-8890 gas chromatograph
GC-8890 gas chromatograph adopts 10/100M adaptive Internet communication technology, which can form a LAN with high communication efficiency; Realized long-distance data transmission; One chromatograph can connect to three computers; One chromatograph can connect multiple chromatographs (up to 5000) simultaneously and perform operational control.
Reliable and comprehensive anti control technology, all instrument parameters can be remotely set through a computer and spectral processing can be performed.
Supporting multiple injection methods such as automatic sampler, automatic headspace sampler, fragmentation sampler, etc., true unmanned online analysis is achieved through network transmission and control.
Adopting new automatic flow/pressure control EPC and EFC technologies, all gas path parameters (flow and pressure) are digitally controlled, and the working modes are divided into three types: cross flow, constant pressure, and split flow. It can perform a 4-stage program to increase pressure, with a pressure accuracy of 0.01KPa and a flow rate of 0.01sccm.
Quick temperature rise and fall structure, capable of achieving an interrogation rate of 80 ℃/min; Realize operation at room temperature environment; Under liquid nitrogen conditions, it supports a wide range of temperature control from -80 ℃ to 450 ℃.
Adopting intelligent hydrogen and air automatic control technology, the solenoid valve automatically switches on and off the gas, thereby achieving true automatic ignition function.
It has 4 external event functions, supports multi valve switching, and realizes the application of multidimensional chromatography system.
Advanced gas path process enables the simultaneous application of hydrogen flame detector and thermal conductivity detector. Dual thermal conductivity detectors can also be used simultaneously.
By adopting the latest digital integrated circuit devices and technologies, the instrument control accuracy (temperature control can reach 0.1 ℃) and the stability and reliability of its performance are comparable to those of imported instruments.
Advanced dual automatic rear door opening function, which can automatically adjust the opening and closing angle according to temperature changes.
The instrument adopts a 5.7-inch color screen display, which displays two spectra simultaneously, and can be equipped with a touch screen.

GC-8890 gas chromatograph temperature control indicators:
Temperature controlled area: 6 channels
Temperature control range: 4 ℃ -450 ℃ above room temperature, increment: 1 ℃, accuracy: ± 0.1 ℃
Program heating order: 16 orders
Cheng speed: 0.1-39 ℃/min (ordinary type), 0.1-80 ℃/min (high-speed type)

Pressure and flow control indicators:
Pressure and flow measurement: pointer pressure gauge method, electronic pressure and flow method
Full electronic gas pressure and flow measurement system: maximum measurement channels per module: 16 channels
EPC and EFC working modes: 3 types (constant current mode, constant voltage mode, and split current mode)
EPC and EFC working gases: 4 types (nitrogen, hydrogen, air, helium)
EPC, EFC lift: 4th order
EPC and EFC control range: pressure: 0-0.6Kpa, flow rate: 0-100sccm or 0-500sccm (air)
EPC and EFC control accuracy: pressure 0.01kpa, flow 0.01sccm
Pressure sensor:
Accuracy: Full scale<± 2 ℃ Reproducibility:<± 0.05kpa
Temperature coefficient: ＜ ± 0.01kpa/℃ Range: 0-0.3kpa or 0-0.6kpa
Flow sensor:
Accuracy:<± 5% of full scale Reproducibility:<± 0.5% (full scale) Range: 0-500sccm

Technical specifications of detector:
Hydrogen Flame Ionization Detector (FID) Thermal Conductivity Detector (TCD)
Detection limit: Mt ≤ 3 × 10-12 g/s (n-hexadecane) Sensitivity: S ≥ 4000mV. ml/mg (C6H6) (can be amplified by 1, 2, 4, 8 times)
Noise: ≤ 5 × 10-14A Noise: ≤ 10uV
Drift: ≤ 1 × 10-13 A/30min Baseline drift: ≤ 30UV/30min
Linear range: ≥ 106 Linear range: ≥ 104
Maximum operating temperature: ≤ 450 ℃

Electron Capture Detector (ECD) Flame Photodetector (FPD)
Detection limit: ≤ 1 × 10-14g/s (r-666) Detection limit: Mt ≤ 2 × 10-11 g/s (sulfur in methyl parathion)
Noise: ≤ 15uV Noise: Rn ≤ 50uV
Baseline drift: ≤ 20UV/30min Baseline drift: Rd ≤ 20UV/30min
Linear range: 104 Linear range: ≥ 105
Radiation source: Ni63

Nitrogen phosphorus detector (NPD)
Mt ≤ 8 × 10-13 g/s (azobenzene); ≤ 5 × 10-13 g/s (malathion)
Noise: Rn ≤ 2 × 10-12A
Baseline drift: Rd ≤ 2 × 10-13 A/30min
Linear: ≥ 105