hplc chromatography in determination of Aldehydes and Ketones

The principle of hplc chromatography in stationary pollution source waste gas - Determination of aldehydes and ketones

The aldehydes and ketones in the waste gas from the fixed pollution sources react with the 2,4-dinitrophenylhydrazine (DNPH) in the absorption liquid in an acidic medium to generate stable 2,4-dinitrophenylhydrazone derivatives thing. After extracting and concentrating with dichloromethane, it is separated by high performance liquid chromatography and detected by ultraviolet or diode array detector. Qualitative by retention time, quantitative by external standard method.The chemical reaction is as follows

Instruments and Equipment

Instruments name	Model
High performance liquid chromatography(HPLC)	LC3100
Quaternary low pressure gradient pump	P3200Q
Autosampler	AS3200
Column oven	CT3200
Diode array detector	DAD3200

Chromatographic conditions

Column：C18 column, 4.6×250mm, 5μm, pH range: 2-11, double-terminated reversed-phase column or equivalent column with octadecylsilane-bonded silica gel (ODS) as packing material
Mobile phase：A: Acetonitrile B: Water C: Methanol
Flow rate：1.0 mL/min
Injection volume：10 μl
Column temperature：35℃
Detector：DAD
Detection wavelength：360 nm

Gradient elution procedure

Time（min）	Acetonitrile（%）	Water（%）	Methanol（%）
0	20	35	45
6	0	30	70
20	0	20	80
30	35	20	45
33	20	35	45
43	20	35	45

Chromatogram of 12 kinds of aldehydes and ketones-DNPH derivatives mixed standard

1-formaldehyde-DNPH; 2-acetaldehyde-DNPH; 3-acrolein-DNPH; 4-acetone-DNPH; 5-propionaldehyde-DNPH; 6-butenal-DNPH; 7-2-butanone-DNPH; 8-butyraldehyde-DNPH; 9-benzaldehyde-DNPH; 10-isovaleraldehyde-DNPH; 11-n-pentanal-DNPH; 12-n-hexanal-DNPH.

12 kinds of aldehyde and ketone compounds DNPH peak situation table

Peak No.	Compound name	Retention time	Peak height	Peak area	Resolution
1	Formaldehyde DNPH	7.417	180	1891	9.029
2	acetaldehyde DNPH	10.000	107	1248	10.512
3	Acrolein DNPH	13.384	89	1187	1.249
4	Acetone DNPH	13.817	70	963	2.490
5	propionaldehyde DNPH	14.684	72	979	9.478
6	crotonaldehyde DNPH	18.167	55	857	4.158
7	2-Butanone DNPH	19.967	52	822	0.664
8	n-Butyraldehyde DNPH	20.284	48	764	6.990
9	Benzaldehyde DNPH	23.350	40	643	3.658
10	Isovaleraldehyde DNPH	24.800	45	697	3.052
11	n-valeraldehyde DNPH	26.017	43	680	13.588
12	n-hexanal DNPH	31.500	37	576	--

Chromatograms of 12 aldehydes and ketones after derivatization

1-Formaldehyde DNPH, 2-acetaldehyde DNPH, 3-propanal DNPH, 4-propanal DNPH, 5-propanal DNPH, 3'-propanal DNPH polymer, 6-butenal DNPH, 7-2-butanone DNPH, 8-n-butyraldehyde DNPH, 9-benzaldehyde DNPH, 10-isovaleraldehyde DNPH, 11-n-valeraldehyde DNPH, 12-n-hexanal DNPH

Summary

Wayeal instrument hplc chromatography can realize the separation and detection of 12 kinds of aldehydes and ketones;
In order to ensure that the blank is not disturbed by the environment, the brown reagent bottle storing the DNPH saturated absorption solution should be washed with hot water and ultrapure water in advance, and then dried at 130 °C for 3 hours;
The derivatization reaction produces water. When drying with anhydrous sodium sulfate, the particles should flow freely. At this time, the system reaches an anhydrous state, thus entering the concentration step.

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