Non-targeted workflow for identification of antimicrobial compounds in animal feed using bioassay-directed screening in combination with liquid chromatography-high resolution mass spectrometry

Figures & data

Figure 1. Flowchart presenting the different steps in the unknown identification procedure.

Figure 2. Flowchart of data reduction after baseline correction for both MetAlign® approaches. The different symbols represent different compounds, the triangle is the compound of interest.

Table 1. Tentative candidate list for sample III; the numbers correspond to the figures in the supporting information.

No.	Mass [m/z]	Formula [M]	Species	Intensity (×10^8)	Tentative identity (based on MS/MS fragmentation)
1	298.3468	C20H43N1	+H	9.9	Octyldecyldimethylammonium
2	284.3312	C19H41N1	+H	9.9	Heptyldecyldimethylammonium
3	270.3155	C18H39N1	+H	4.9	Hexyldecyldimethylammonium and Dioctyldimethylammonium
4	326.3781	C22H47N1	+H	4.4	Didecyldimethylammonium*
5	324.3625	C22H45N1	+H	1.1	Decyldecylenedimethylammonium
6	312.3625	C21H45N1	+H	0.9	Nonyldecyldimethylammonium
7	340.3574	C22H45N1O1	+H	9.9	Dodecyldecanamide
8	342.3730	C22H47N1O1	+H	9.8	Hydroxydidecyldimethylammonium
9	356.3523	C22H45N1O2	+H	3.8	Decylhydroxydecanamide
10	384.3836	C24H49N1O2	+H	1.9	Didecyldimethylammonium methylester

*Confirmed according to CD 2002/657/EC (Commission Decision 2002/657/EC. 2002)

Figure 3. Result of the targeted MS/MS analysis of m/z 326.3781 in (a) the bioactive fraction of sample III and (b) a DDAC reference standard solution (2 mg L⁻¹).

Figure 4. Structure of DDAC (m/z 326.378) and tentative product ion.