GB/T 35104-2017 in English

1. Background and significance of the standard

GB/T 35104-2017 specifies the determination method of phthalate plasticizers in fertilizers, using gas chromatography-mass spectrometry (GC-MS). This method is applicable to the detection of six phthalate compounds in compound fertilizers, organic fertilizers, slow-release fertilizers and other nitrogen, phosphorus and potassium fertilizers: DMP, DEP, DBP, BBP, DEHP, DNOP and DINP, DIDP, with a detection limit range of $0.1~\mathrm{mg/kg}$ to $0.5~\mathrm{mg/kg}$.

2. Comparison of standard frameworks

3. Method Summary and Technical Key Points

Method Summary:The phthalate plasticizers in the sample were extracted with a mixture of n-hexane and dichloromethane as solvent, and then subjected to gas chromatography-mass spectrometry for determination. Selected ion monitoring mode (SIM) scanning and external standard method for quantification were used.

Technical Key Points:

• Electron impact ionization (EI) source and quadrupole detector were used;
• The chromatographic column was 30m × 0.25mm, and the stationary phase was diphenyl-dimethylarylene siloxane copolymer;
• Column temperature program: initially 40℃ for 2 minutes, then increased to 325℃ at 15℃/min and maintained for 10 minutes.

4. Implementation suggestions and precautions

Implementation suggestions:

1. Prepare samples strictly according to the standards to ensure sample representativeness;
2. Reagents and instruments must meet purity and performance requirements;
3. Calibrate equipment regularly to ensure the accuracy of the measurement results;
4. Add internal standards to blank tests to optimize method sensitivity.

Precautions:

• Pay attention to the solvent ratio and ultrasonic time control during extraction;
• Avoid matrix interference during chromatographic analysis, and perform solid phase extraction purification when necessary;
• Qualitative judgment requires comprehensive retention time and relative ion abundance deviation.

5. Analysis of the evolution of standard technology

GB/T 35104-2017 is the first standard for the detection of phthalate plasticizers in fertilizers, filling the gap in this field in China. With the growth of environmental monitoring needs and the advancement of instrument technology, the standard may be optimized in the following aspects in the future:

• Expand the detection range to more phthalate compounds;
• Introduce more sensitive analytical methods such as gas chromatography-mass spectrometry tandem technology;
• Add sample pretreatment methods to improve detection efficiency.