1. Atomic emission spectrometry .
Atomic emission spectrometry
with inductively coupled plasma (ICP-AES) analysis
of trace elements in Camellia sinensis tea
Dragica Doneva1, Trajče Stafilov2, Zorica Arsova-Sarafinovska1,
Katerina Starkoska1, Maja Shishovska1
1Institute for Public Health of the Republic of Macedonia, Medicines Quality Control Department,
50 Divizija, No. 6, 1000 Skopje, Republic of Macedonia 2Institute of Chemistry, Faculty of Natural Sciences and Mathematics, Ss. Cyril and Methodius University, Skopje, Republic of Macedonia
Introduction
Sample preparation and analysis
Camellia sinensis is an evergreen shrub or small tree that is usually cultivated for its leaves. Two major varieties are grown: sinensis for Chinese teas, and assamica for Indian Assam teas. White tea, yellow tea, green tea, oolong, pu-erh tea, and black tea are all harvested from one or the other, but are processed differently to attain varying levels of oxidation. The atomic emission spectrometry with inductively coupled plasma (ICP-AES) tehnique was used for determination of trace elements presence and their contents in Camellia sinensis teas and its tea mixtures. Samples were collected from macedonian market originating from Macedonia, Serbia and Poland. For sample preparation microwave digestion system using HNO3 and H2O2 was applied. The following trace elements: Al, Ba, Ca, Cd, Cr, Cu, Mn, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, Sr, V and Zn were determined in several types of tea products.
Microwave digestion system using HNO3 and H2O2 was applied for sample preparation while the contents of elements were determined by atomic emission spectrometry with inductively coupled plasma, ICP-AES (Varian, 715ES).
Results
Table 1. Results obtained by testing Camellia sinensis teas
sampled from macedonian market
Trace
element
Origin/ tea sample number/ (mg/kg)
Macedonia
Serbia
Poland 1 2 3 4 5 6 Al
843
774
544
346
665
692
781
742
838
869
775
1066 As
<1 Ba
17.3
14.8
10.2
9.3
17.7
18.3
18.9
26.5
24.6
31.7
12.2
14.0 Ca
4608
5152
4111
3406
2507
2919
4337
2882
6059
6072
3363
3779 Cd
<0.05
0.09
0.06 Cr
0.50
0.52
0.27
0.66
0.23
0.60
0.30
0.34
0.45
0.26
0.32 Cu
12.1
11.5
9.0
7.8
11.2
11.1
12.9
12.0
15.6
7.1
8.4 Fe
289
194 83
282 75 87
141
163
108
247
103
137 K
10013
8664
6698
7105
5719
9046
10287
8389
7708
9476
6514
7291 Li
0.08
0.36
0.12
0.07
0.17
0.90
0.31 Mg
2273
2678
2013
3072
1387
1866
2312
1767
2400
2559
1935
2080 Mn
581
349
294
205
617
540
597
511
503
286
357 Mo
0.05
0.10
0.01
0.03 Na 14 47
215 56 16 11
184
114
122 90 64 Ni
2.51
1.71
1.39
1.57
1.56
3.2
3.54
2.72
2.42
1.21
1.55 P
1632
1098
7822
789
679
1176
1549
1120
1076
1351
776
881 Pb
0.9
0.7
0.4
0.6
2.0
1.6
1.0
1.5
1.1
0.2 Sr
16.5
17.0
38.5
21.0
7.00
9.6
8.8
11.3
15.9
26.2
17.1 V
0.76
0.14
0.21
0.13 Zn
18.6
14.5
11.0
15.3
12.3
16.6
19.6
22.1
20.2
10.9
Figure 1. Pb contents at Camellia sinensis teas and tea mixtures
Figure 2. Cu contents at Camellia sinensis teas and tea mixtures
Figure 4. Cu contents at Camellia sinensis teas homemade and imported
Figure 3. Pb contents at Camellia sinensis teas homemade and imported
Conclusion
The result for the content of all analyzed elements showed differences between sampled teas depending on manufacturer. The content of elements in these tea samples generally followed the usual pattern: К>Ca>Mg>P. That means that K, Ca and Mg were the most abundant elements (10287 mg/kg, 6072 mg/kg, 3072 mg/kg, respectively). Mo and V were not detected, and the elements: Na and Li were detected at the widest ranges. Obtained assay data for As, Pb and Cd are compared with the limits of the toxic metals allowed by the World Health Organization (WHO) (0.3, 10.0 and 1.0 mg kg-1 for Cd, Pb and As, respectively) and the British Pharmacopeia (BP) (1.0 and 5.0 mg/ kg for Cd and Pb, respectively). These elements were detected at allowed quantities. The results for the content of all analyzed elements showed the expected variation among sampled teas and therefore these tea products may not produce any health risks for human consumption as sources of toxic metals.
INTERNATIONAL SYMPOSIUM AT FACULTY OF MEDICAL SCIENCES
24 November, 2015, Shtip