Carboxylated Multiwalled Carbon Nanotubes as Dispersive Solid-Phase Extraction Sorbent to Determine Eighteen Polychlorinated Biphenyls in Vegetable Samples by Gas Chromatography-Mass Spectrometry

Table 1

Retention times, characteristic ions, and their relative abundance of the 18 PCBs analyzed in the present study.

No	IUPAC number	IUPAC name	Formula	Retention time (min)	Time window (min)	Characteristic ions (m/z)	Relative abundances (%)
1	PCB28	2,4,4′-trichlorobiphenyl	C12H7Cl3	12.373	5.00–13.00	256/186/150	100/68/18
2	PCB52	2,2′,5,5′-tetrachlorobiphenyl	C12H6Cl4	13.597	13.00–16.00	292/220/110	100/82/20
3	PCB101	2,2′,4,5,5′-pentachlorobiphenyl	C12H5Cl5	17.233	16.00–18.00	326/254/127	100/59/18
4	PCB81	3,4,4′,5-tetrachlorobiphenyl	C12H6Cl4	18.448	18.00–19.50	292/220/110	100/40/15
5	PCB77	3,3′,4,4′-tetrachlorobiphenyl	C12H6Cl4	18.913		292/220/110	100/43/13
6	PCB123	2′,3,4,4′,5-pentachlorobiphenyl	C12H5Cl5	20.068	19.50–22.00	326/254/127	100/40/11
7	PCB118	2,3′,4,4′,5-pentachlorobiphenyl	C12H5Cl5	20.184		326/254/127	100/35/10
8	PCB114	2,3,4,4′,5-pentachlorobiphenyl	C12H5Cl5	20.710		326/254/127	100/46/12
9	PCB153	2,2′,4,4′,5,5′-hexachlorobiphenyl	C12H4Cl6	21.329		360/290/145	100/65/24
10	PCB105	2,3,3′,4,4′-pentachlorobiphenyl	C12H5Cl5	21.469		326/254/127	100/36/14
11	PCB138	2,2′,3,4,4′,5′-hexachlorobiphenyl	C12H4Cl6	22.689	22.00–24.00	360/290/145	100/62/20
12	PCB126	3,3′,3,4,4′,5-pentachlorobiphenyl	C12H5Cl5	23.136		326/254/127	100/30/13
13	PCB167	2,3′,4,4′,5,5′-hexachlorobiphenyl	C12H4Cl6	24.174	24.00–25.00	360/290/145	100/38/16
14	PCB156	2,3,3′,4,4′,5-hexachlorobiphenyl	C12H4Cl6	25.328	25.00–26.00	360/290/145	100/34/15
15	PCB157	2,3,3′,4,4′,5′-hexachlorobiphenyl	C12H4Cl6	25.622		360/290/145	100/45/17
16	PCB180	2,2′,3,4,4′,5,5′-heptachlorobiphenyl	C12H3Cl7	26.250	26.00–27.00	394/324/162	100/72/36
17	PCB169	3,3′,4,4′,5,5′-hexachlorobiphenyl	C12H4Cl6	27.470	27.00–29.00	360/290/145	100/40/17
18	PCB189	2,3,3′,4,4′,5,5′-hexachlorobiphenyl	C12H3Cl7	29.425	29.00–31.00	394/324/162	100/50/23

Quantitative ion.