[Retracted] Chemical Speciation and Potential Mobility of Heavy Metals in the Soil of Former Tin Mining Catchment

Table 5

Results of analysis of standard reference materials (SRM) in comparison with certified values.

Standard reference material	Analysed SRM value	Certified SRM value	Recovery%
Sequential extraction
SRM-027-050-Soil (𝑛=3)
Step 1
As	4.19±0.40	4.98.0±0.38	88
Cr	3.13±0.10	2.87±0.13	85
Zn	4.08±0.79	3.94±0.39	100
Cu	34.24±1.6	46.73±1.8	69
Pb	73.11±2.00	64.20±2.00	101
Sn	178±5.00	195±2.00	103
Step 2
As	3.08±0.30	3.12±0.34	90
Cr	2.89±0.14	2.98±0.19	85
Zn	100.18±4.00	88.84±3.00	92
Cu	102.38±2.0	129.0±2.5	101
Pb	62.30±3.00	65.28±3.00	99
Sn	112±4.00	136±5.00	100
Step3
As	1.18±0.23	1.02±0.32	95
Cr	100.12±4.00	105.00±5.00	106
Zn	52.28±2.00	65.74±3.00	103
Cu	29.28±2.0	36.32±2.5	100
Pb	10.10±2.00	8.80±3.00	102
Sn	70±2.00	72±3.00	100
Step 4
As	0.18±0.03	0.20±0.52	120
Cr	73.33±5.00	60.56±4.00	128
Zn	98.00±5.00	87.34±4.00	120
Cu	20.98±0.88	19.93±2.00	115
Pb	14.23±0.90	10.53±1.00	104
Sn	40±4.00	35±2.00	111
Total digestion
CRM-027-050-Soil (𝑛=3)
As	9.86±1.00	10.78±1.00	97
Cr	157.95±4.00	180.45±4.00	108
Zn	251.16±4.00	250.06±5.00	99
Cu	198.18±4.00	235.75±3.00	112
Pb	143.91±2.00	155.31±2.00	94
Sn	390±5.00	381±4.00	99