... purchased from supermarket (Changsha, China) All of these products examined are natural dietary supplements for male sexual health, not for therapy of ED The drugs are forbidden to be added in ... containing 20 mmol/l ammonium acetate and 0.2% formic acid (v/v) The gradient elution was programmed as follows: A was maintained at 35% within the first 10 min, then linearly increased to 80% during ... often been added into fluid products such as wine, beverage, and oral liquid formulation, etc Hence, eight liquid products for examination (five oral liquid formulation, two wines, and one beverage,...