How to detect the purity of sodium gluconate? What test materials are needed？ What are the methods to detect the purity of sodium gluconate?
The salt taste of sodium gluconate is close to that of table salt, and the threshold value is five times that of table salt. It can be used instead of salt to improve characteristics, adjust fermentation, and endow food with functions such as preservation and dehydration; It can be used in water treatment, electroplating, metal and non-metal surface cleaning, cement production, pharmaceutical industry and other fields
1. Materials and equipment required for sodium gluconate purity test
Reagents: sodium gluconate (analytical purity), methanol (chromatographic purity), phosphoric acid (analytical purity), ultrapure water, sodium hydroxide, copper sulfate, glacial acetic acid, quinaldine red, perchloric acid
Instrument and equipment:
Dionex high performance liquid chromatography system: P680 HPLC pump, asi-100 automated sampleinjector, thermostatted column compartmenttcc-100, PDA-100 photodiode array detector; Reversed phase chromatographic C18 column, Apollo C18 (250mm * 4.6mm); Ll – QOR millipore ultra pure water: kq520de numerical control ultrasonic cleaner, dhg-9145a blast drying oven, unicouv-2102pc ultraviolet visible spectrophotometer; Tim840 traction Manager (working electrode: phg311-9; Reference electrode: ref921); Wzz-2a automatic digital display polarimeter
2. Test method for purity of sodium gluconate
Purity test of sodium gluconate:
Accurately weigh 1.5040g sodium gluconate, dry it at 105 ℃ to constant weight, dissolve it with ultrapure water, fix the volume to 50ml, and dilute the solution to 15ml.. After 0.45um filter membrane and ultrasonic treatment, the sample can be analyzed on HPLC instrument. Six of them are standard curves. The mobile phase of HPLC was methanol ∶ water ∶ 1% phosphoric acid (2:48:50), the flow rate was 1.0ml/min, the column temperature was 25 ℃, the injection volume was 15ul, and the detection wavelength was 210nm.
Accurately weigh 13.4779g sodium gluconate, dry it at 105 ℃ to constant weight, fix the volume to 50ml with distilled water and 25ml solution. Take 1ml of solution, add NaOH and CuSO4 solution, and fully stir until the precipitation does not disappear.Dilute the collected filtrate to 50ml with distilled water to obtain a series of concentration standard solutions.
Nonaqueous titrationIndicator color development method:
Accurately weigh 1.0288g sodium gluconate, bake at 105 ℃ to constant weight, dissolve with glacial acetic acid and cool to 300ml. Dilute sodium gluconate glacial acetic acid solution to 100ml, add a few drops of quinine red solution, and titrate until colorless.
Application agreement law：
Accurately weigh 1.9400g sodium gluconate, bake at 105 ℃ to constant weight, dissolve with glacial acetic acid and cool to 500ml. Dilute sodium gluconate glacial acetic acid solution to 50ml, and titrate sodium gluconate glacial acetic acid solution with standard solution.
Accurately weigh 13.4070g sodium gluconate, dry it at 105 ℃ to constant weight, and fix the volume to 50ml and 20ml with distilled water. Take water as blank, measure the rotation 5 times according to the law, take the average value and draw the standard curve.