Table 1. Comparison of the Developed Method for the Determination of Vitamin D₃ with Similar Methods.

no.	extraction technique	detection method	LOD (μg L–1)	linear range (μg L–1)	recovery (%)	RSD (%)	concentration in the real sample (μg L–1)	ref
1	SPE on C18 column	SFCa and reverse phase liquid chromatography/mass spectrometry	10	20–200	84.3–109.6	<7.1	Baby Ddrops (10.35–10.77 μg), vitamin AD drops (11.34–11.76 μg)	(13)
2	DLLMEb	liquid chromatography with DAD-APMSc	10–500	1–100	88–103	<6.8	Spinach (NDf), Iceberg lettuce (ND), Cos lettuce (ND), Lamb’s lettuce (ND), infant formula (0.082 μg g–1), infant cereals (0.071 μg g–1)	(19)
3	liquid–liquid extraction	spectrophotometry	0.004	12–315	100.6–101.1	<0.14	milk (10–13), carrot (ND), egg yolk (14–16 ng g–1), poultry feed (ND, 0.10–0.12 ng g–1), mushrooms (61–65 ng g–1), algae (ND), pharmaceutical 200 IU (4920–4950 ng/tablet), serum (19–23 ng mL–1), Tuna fish (52–59 ng g–1)	(20)
4		HPLC-UVd	NMe	100–132,000	99.6–105.5	ND	pharmaceutical (35.04 μg g–1)	(21)
5	glassy carbon electrode and separation by polyethylene glycol	voltammetry	NM	0.005–1 mM	98.9–102.8	NM	0.45–0.99 mM	(22)
6	hDES–SBSE	spectrophotometry	0.08	1–1000	96.8–99.0	<4.3	soft gelatine caps (48.6), milk (without vitamin D3) (ND), Baby Ddrop (49.0)	this research

^aSFC, supercritical fluid chromatography.

^bDLLME, dispersive liquid–liquid microextraction.

^cDAD-APMS, liquid chromatography with diode array and atmospheric pressure chemical ionization-mass spectrophotometry.

^dHPLC-UV, high-performance liquid chromatography with an ultraviolet detector.

^eNM, not mentioned.

^fND, not detected.