Method for preparing colloidal gold and detection test paper for detecting lead ions

The invention relates to a method for preparing colloidal gold. The method comprises the steps of placing chloroauric acid solution with a concentration of 0.3 g/L in a conical flask, using a thermostatic electromagnetic stirrer to heat the chloroauric acid solution to boil the solution and maintaining the boiling for 5 min, adding 5ml of 1% sodium citrate water solution, to enable the solution to be bright wine red; cooling the solution at room temperature, storing the solution in a refrigerator for reservation, and obtaining a large-particle-diameter colloidal gold solution with a diameter of about 50 nm for marking goat anti mouse IgG. According to the method for preparing colloidal gold, the technical shortcomings of an existing instrument in detecting lead ions can be effectively overcome, heavy metal lead ions are quickly detected, and the colloidal gold has the advantages of being high in sensitivity, short in operation time and high in detection accuracy. 本发明涉及种胶体金的制备方法，所述方法包括如下步骤：将浓度为0.3g/L的氯金酸溶液放入锥形