GC6100 Gas Chromatography Case Study: Propanol and Octanol Determination in Workplace Air (GBZ/T 300.84-2017)
2026-11-04
Customer Background: Occupational Hygiene Monitoring
Toxic substances in workplace air are chemical agents in the breathing zone that can harm workers' health. Their management, testing and evaluation follow occupational health standards such as GBZ/T 300.1-2026 and the exposure limit standard GBZ 2.1. Propanol irritates the upper respiratory tract and eyes, depresses the central nervous system at high concentrations and causes headache, nausea, fatigue, drowsiness and ataxia; extremely high levels may lead to confusion and coma. Octanol irritates the respiratory tract, causes coughing and sore throat, defats the skin on repeated contact and carries a risk of chemical pneumonia if aspirated. Reliable trace-level monitoring is therefore essential.
The Analytical Challenge
Workplace air samples are collected on activated carbon tubes, and the target alcohols must be recovered completely before analysis. Laboratories need sharp, well-resolved peaks for isopropanol, n-propanol and isooctanol, detection limits low enough to support occupational exposure limits, and repeatable response from 0.50 to 100 mg/L.
The Solution: GC6100 with FID and ALS6100 Autosampler
Wanyi Technology applied its GC6100 gas chromatograph with an FID detector and an ALS6100 liquid autosampler, following GBZ/T 300.84-2017 (Methanol, Propanol and Octanol). Samples are desorbed with an isobutanol-carbon disulfide desorption solution and injected directly.
System Configuration
| No. | Item | Qty |
|---|---|---|
| 1 | GC6100 gas chromatograph | 1 unit |
| 2 | FID detector | 1 unit |
| 3 | ALS6100 liquid autosampler | 1 unit |
| 4 | SmartLab CDS 2.0 chromatography workstation | 1 set |
| 5 | Quartz capillary column, 30 m x 0.32 mm x 1.0 um | 1 pc |
Reagents and Standards
| Reagent / Standard | Purity |
|---|---|
| Carbon disulfide | GC >= 99.9% |
| n-Propanol | GC >= 99.8% |
| Isopropanol | GC >= 99.9% |
| Isooctanol | GC >= 99.5% |
| Isobutanol | GC >= 99.5% |
Sampling, Preparation and Conditions
- Sampling: activated carbon tube (100 mg / 50 mg, solvent desorption type) on an air sampler at 20-500 mL/min; an unexposed sealed tube serves as field blank.
- Desorption: carbon from blank and sample tubes desorbed for 30 min, solution taken for analysis.
- Desorption solution: 1.0 mL isobutanol to 100 mL with carbon disulfide.
- Standards: 0.050 g each of n-propanol, isopropanol and isooctanol to 5.0 mL gives 10,000 mg/L stock; working solution 1,000 mg/L.
- Conditions: quartz capillary column 30 m x 0.32 mm x 1.0 um; nitrogen carrier at 3.0 mL/min; FID with hydrogen and air generators; ALS6100 autosampler.
Results
Peak Identification and System Suitability (100 mg/L)
| Compound | Retention time (min) | Peak area (pA*s) | Resolution | Plates |
|---|---|---|---|---|
| Isopropanol | 2.495 | 31.687 | 15.106 | 14,581 |
| n-Propanol | 3.795 | 38.096 | 8.031 | 28,777 |
| Isobutanol | 4.546 | 6552.008 | 65.871 | 34,685 |
| Isooctanol | 11.160 | 53.216 | n.a. | 187,148 |
All peaks are sharp and well separated, with resolution above 1.5.
Linearity, 0.50 - 100 mg/L
| Compound | Calibration equation | R |
|---|---|---|
| Isopropanol | Y = 0.64142X + 0.03663 | 0.99995 |
| n-Propanol | Y = 0.77564X + 0.10372 | 0.99995 |
| Isooctanol | Y = 1.09856X - 0.19400 | 0.99990 |
Seven levels from 0.50 to 100 mg/L give R above 0.9999 for all three compounds.
Detection and Quantification Limits (n = 8, 1.0 mg/L)
| Item | Isopropanol | n-Propanol | Isooctanol |
|---|---|---|---|
| Mean area (pA*s) | 0.661 | 0.718 | 1.168 |
| Standard deviation | 0.035 | 0.033 | 0.043 |
| RSD (%) | 5.279 | 4.646 | 3.693 |
| MDL (ug/mL) | 0.16 | 0.14 | 0.11 |
| MQL (ug/mL) | 0.54 | 0.49 | 0.35 |
| Minimum detectable air level (mg/m3) | 0.11 | 0.09 | 0.07 |
| Minimum quantifiable air level (mg/m3) | 0.36 | 0.32 | 0.24 |
Desorption Efficiency
| Spike level | Isopropanol (%) | n-Propanol (%) | Isooctanol (%) |
|---|---|---|---|
| 1.0 mg/L | 110 - 112 | 110 - 112 | 113 - 119 |
| 10 mg/L | 91.2 - 95.9 | 86.6 - 91.4 | 98.9 - 104 |
| 50 mg/L | 90.8 - 96.7 | 87.0 - 92.2 | 98.6 - 102 |
| 100 mg/L | 89.9 - 93.9 | 85.8 - 89.6 | 96.9 - 99.8 |
| Average (%) | 97.6 | 94.3 | 104 |
Repeatability, Six Parallel Runs
| Level | Isopropanol RSD (%) | n-Propanol RSD (%) | Isooctanol RSD (%) |
|---|---|---|---|
| 10 mg/L | 2.674 | 2.584 | 2.876 |
| 50 mg/L | 2.857 | 2.966 | 2.770 |
| 100 mg/L | 2.074 | 2.065 | 2.219 |
Peak area RSD stays within 2.1 - 3.0%, far below the 10% limit required by the standard.
Real Sample Results and Recovery
| Item | Isopropanol | n-Propanol | Isooctanol |
|---|---|---|---|
| Blank / Sample (mg/L) | ND | ND | ND |
| Spiked mean (mg/L) | 9.673 | 9.460 | 10.169 |
| Average recovery (%) | 96.7 | 94.6 | 102 |
ND means not detected: no target compound was found in the collected samples. Sampling volume 1.5 L, desorption volume 1.0 mL, spike 10.0 ug; recovery of 94.6 - 102% meets the required 90 - 105%.
Conclusion
The Wanyi Technology GC6100 with FID and ALS6100 autosampler, operated to GBZ/T 300.84-2017, resolves propanol and octanol in workplace air with peaks sharp and well separated at resolution above 1.5. Linearity from 0.50 to 100 mg/L exceeds R = 0.9999, six-fold repeatability keeps peak area RSD at 3.0% or below, detection limits are 0.11 - 0.16 ug/mL with quantification limits of 0.35 - 0.54 ug/mL, and spike recovery on real samples reaches 94.6 - 102%. The system is a dependable platform for routine occupational hygiene testing.
Safety Note
Standards and solvents here are volatile and toxic; prepare solutions and pre-treat samples in a fume hood with protective equipment.
