Table 11.

Results of stability studies.

Studies	Average retention time (minutes)		Average peak area (mAu·s)		Average asymmetry of peak		Average number of theoretical plate		RSD (%) of peak area		Recovery (%)
	Peak 1	Peak 2	Peak 1	Peak 2	Peak 1	Peak 2	Peak 1	Peak 2	Peak 1	Peak 2	Peak 1	Peak 2
Potassium guaiacolsulfonate
Standard solution
0 h	5.633	6.734	1607838	588052	0.92	0.91	2030	2902	0.03	0.04	—	—
24 h at refrigerator	5.636	6.734	1607531	587210	0.92	0.90	2032	2902	0.03	0.05	100.0	99.9
24 h at 25°C	5.629	6.731	1606491	585247	0.92	0.91	2028	2899	0.02	0.02	99.9	99.5
Sample solution
0 h	5.630	6.736	1605436	585067	0.93	0.90	2028	2903	0.01	0.01	—	—
24 h at refrigerator	5.631	6.730	1604722	584850	0.93	0.91	2029	2898	0.02	0.01	100.0	100.0
24 h at 25°C	5.629	7.735	1603874	583290	0.92	0.91	2027	2902	0.05	0.05	99.9	99.7
Sodium benzoate
Standard solution
0 h	12.380		1906212		0.99		27250		0.06		—
24 h at refrigerator	12.372		1905065		0.98		27214		0.02		99.9
24 h at 25°C	12.366		1903771		0.99		27186		0.01		99.9
Sample solution
0 h	12.375		1904980		0.99		27226		0.01		—
24 h at refrigerator	12.381		1904544		0.99		27249		0.02		100.0
24 h at 25°C	12.367		1903276		0.99		27192		0.01		99.9