Table 2. Commercial Manuka Samples Purchased from Singapore.

		compound concentrationa (mg/kg)								classificationb
sample	lepteridine fluorescence (RFU)	lepteridine	4-HPA	3-PA	2-MB	2′-MAP	leptosperin	DHA	MGO	lepteridine (RFU)	lepteridine (LC/MS)	MPI
1	933	8.5	8.2	793	3.5	10.4	497	594	375	√	√	√
2	1046	8.8	4.5	910	3.0	7.8	377	711	542	√	√	√
3	1066	10.6	3.7	1164	3.1	6.2	394	1650	435	√	√	√
4	550	3.5	7.9	445	5.3	5.4	255	192	110	√	√	√
5	816	6.7	3.9	635	7.3	9.0	477	264	515	√	√	√
6	1212	14.6	4.1	1604	9.0	10.1	554	933	1110	√	√	√
7	1171	9.9	4.1	1195	7.1	16.7	411	419	915	√	√	√
8	1270	15.0	3.4	1012	6.2	13.5	615	660	688	√	√	√
9	814	6.8	5.6	509	4.4	6.1	383	262	224	√	√	√
10	1047	6.3	4.0	707	2.5	6.7	347	911	372	√	√	√
11	1390	13.6	2.9	1105	10.5	15.0	733	907	939	√	√	√
12	936	5.4	2.7	1090	18.9	10.0	234	133	682	√	√	√
13	849	5.7	5.5	989	7.9	5.3	318	712	585	√	√	√
14	1500	17.8	9.0	908	3.7	9.7	504	349	777	√	√	√
15	902	5.7	4.4	857	3.0	7.2	360	647	402	√	√	√
16	1199	7.3	6.6	932	2.3	9.5	458	1070	715	√	√	√
17	1334	18.2	6.9	969	3.2	8.6	607	855	888	√	√	√
18	754	8.6	3.3	629	2.7	4.3	278	976	313	√	√	×
19	574	3.5	2.6	338	2.1	2.2	168	160	121	√	√	×
20	539	3.4	3.8	195	3.5	2.7	152	231	103	√	√	×
21	921	3.9	6.3	379	4.5	14.6	123	36	70	√	√	×
22	355	3.0	0.9	730	3.5	3.2	157	85	128	×	√	×
23	481	3.6	2.7	1079	nd	6.4	173	295	140	×	√	×
24	469	1.5	2.2	584	5.0	6.0	168	221	241	×	×	√
25	511	1.2	3.8	402	2.8	4.6	231	165	94	×	×	×
26	458	2.4	5.7	717	1.6	2.9	156	94	117	×	×	×
27	491	1.8	3.6	411	5.1	3.4	276	354	149	×	×	×
28	438	2.5	1.9	296	3.1	3.2	157	157	124	×	×	×
29	422	2.2	2.7	257	2.9	3.4	138	50	69	×	×	×
30	359	1.1	n.d.	103	3.7	3.0	73	57	59	×	×	×
31	314	1.2	n.d.	142	1.0	2.6	75	52	59	×	×	×
32	375	<LOQ	10.4	1330	nd	3.4	63	<10	46	×	×	×
33	342	1.5	4.6	1645	nd	2.6	51	<10	33	×	×	×

^aLepteridine concentrations were quantified using the LC–MS/MS isotope dilution method; 4-HPA, 3-PA, 2-MB, 2′-MAP, and leptosperin concentrations were quantified by HPLC-UV; DHA and MGO concentrations were quantified and supplied by the UMF Honey Association (UMFHA).

^bClassification as monofloral manuka honey (√) or not monofloral manuka honey (×).