Table 4.

Accuracy of the method: mean values from five repetitions (n = 5).

Primary concentration [mmol/L]	Enrichment [%]	Citric acid		Trisodium citrate
		Recovery (%, mean ± SD)	RSD (%)	Recovery (%, mean ± SD)	RSD (%)
2.0	80	99.73 ± 0.75	0.76	100.23 ± 0.64	0.64
	100	100.10 ± 0.81	0.80	99.80 ± 0.68	0.69
	120	100.08 ± 0.55	0.55	100.13 ± 0.63	0.63