Application Range
This method is suitable for the determination of 15 kinds of aldehydes in the soil and sediments (Take the the soil as substrate )
Reference standard: HJ 997-2018 Determination of soil, sediments, aldehydes and ketone compounds— HPLC
Extraction and Derivation Steps
Remove impurities in the sample(stones, leaves, etc.). Accurately weigh 10.0 soil sample (accurate to 0.01g) in 50mL centrifugal tube and add 25mL acetonitrile. Mix with vortex, and centrifuge at 4000r/min for 5min after ultrasound for 10 min. Take the upper clear layer of acetonitrile; Add 15mL acetonitrile to extract again. Then add 10mL acetonitrile to extract for the third time, and merge acetonitrile layers. Accurately take 25mL of it with 6mL DNPH derivative and 20% phosphate solution, then refrigerate it with derivation of 6h. Add 100mL water to dilute and purify.
Purification Steps
SPE column: Welchrom ® C18E column, specification: 1000mg/6mL.
Activation: 10mL acetonitrile, 10mL 20% acetonitrile water, discard;
Sample loading: load all the samples, discard;
Washing: 10mL 20% acetonitrile water, discard;
Elution: elute with acetonitrile in 10mL volumetric flask to be measured.
Chromatographic Conditions
Column: Ultisil ® XB-C18, 4.6*250mm, 5μm.
Mobile phase: acetonitrile: water =65: 35;
Flow rate: 1.0mL/min;
Column temperature: 30 ℃;
Wavelength: 360nm;
Injection volume: 20 μL.
Chromatography or Spike Recovery Rate
Fig. 1. Chromatography of 0.1ppm DNPH standard substance
Fig 2. Chromatography of extracted acetonitrile
Fig 3. Chromatography of soil sample added at 0.2mg/kg
| Substance | Average Recovery Rate | RSD（n=2） | Spike Level |
| Formaldehyde-DNPH | 72% | 1.69% | 0.2 mg/kg |
| Acetaldehyde-DNPH | 112% | 4.06% | 0.2 mg/kg |
| Acrolein-DNPH | 99% | 5.00% | 0.2 mg/kg |
| Acetone-DNPH | 104% | 1.23% | 0.2 mg/kg |
| Propanal-DNPH | 105% | 3.53% | 0.2 mg/kg |
| Crotonaldehyde-DNPH | 107% | 1.45% | 0.2 mg/kg |
| Butanal-DNPH | 100% | 3.52% | 0.2 mg/kg |
| Benzaldehyde-DNPH | 106% | 3.86% | 0.2 mg/kg |
| 3-Methyl butanal-DNPH | 107% | 4.26% | 0.2 mg/kg |
| Valeraldehyde-DNPH | 105% | 1.85% | 0.2 mg/kg |
| o-Tolualdehyde-DNPH | 87% | 0.59% | 0.2 mg/kg |
| m-Tolualdehyde-DNPH | 85% | 2.79% | 0.2 mg/kg |
| p-methyl benzaldehyde-DNPH | 91% | 5.10% | 0.2 mg/kg |
| N-hexanal-DNPH | 104% | 2.93% | 0.2 mg/kg |
| 2,5-Dimethylbenzaldehyde-DNPH | 97% | 1.97% | 0.2 mg/kg |
Spike Recovery Rate Table
| P/N | Name | Specification |
| 00559-11007 | SPE column | Welchrom® C18E，1000mg/6mL，30pk |
| 00837-05006 | 50mL centrifuge tube with screw mouth and apical bottom | Disposable centrifuge tube, flat cap,conical bottom, RCF12000xg, 15 mL, 50/ pk without sterilization |
| 00824-31001 | Welch SPE instrument | 12 ports square cylinder |
| 00821-32291 | Caps and septa | Pre-slit red PTFE/white Silicone septa, 9mm blue short screw-thread polypropylene cap, 6mm centre hole, 100/pk |
| 00821-40927 | Vials | 2ml wide opening short screw-thread vial with write-on spot, clear, 11.6*32mm , 100/pk |
| 00201-31043 | HPLC column | Ultisil® XB-C18，4.6*250mm，5μm |
If you have any problem or require further information, please contact info@welchmat.com.
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