+86 199 6547 6623 info@wayealtech.com facebook

Multifunctional Ion Chromatograph for Boric Acid Detection

This article mainly introduces how to use ion chromatography to detect borate in cosmetics

Boric acid is used as a preservative in cosmetics and also as a pH adjuster to increase product viscosity and stabilize formulations. External use of boric acid is generally not very toxic, but its oral toxicity is strong. It can be quickly absorbed from the gastrointestinal tract and damaged skin. The lethal dose is 15-20g for adults and 3-6g for children. Boric acid and borate are slowly excreted in the human body, and long-term intake can cause accumulation and cause chronic poisoning.

1 Ion chromatography experiment

Ion Chromatograph: IC6600
Chromatography pump: P6600
Detector: DC6600, equipped with conductivity detector

IC6600

2,Chromatographic conditions

Column Chromatographic column for borate 9x250mm
Mobile phase 3 mmol/L methanesulfonic acid+60 mmol/L mannitol
Regenerated liquid 25mmol/L Tetramethylammonium Hydroxide+15mmol/L Mannitol
Mobile phase flow rate 1.0mL/min Regenerated liquid flow rate 1.0mL/min
Column temperature 30℃ Conductivity cell temperature 35℃
Current 0mA Injection volume 25μl

3 Pre-treatment

▶ Determination of soluble borate

(1) Weigh 1.0 g of sample (accurate to 0.0001 g) into a 10 mL plastic colorimetric tube with stopper,
(2) Add 7 mL methanol solution and vortex for 1 min,
(3) Dilute the volume to 10 mL with methanol solution, shake well, and centrifuge at 10000 rpm for 5 min.
(4) Take 1 mL of the supernatant, put it in a 10 mL plastic volumetric flask, dilute to the mark with water, shake well,
(5) Pass the RP column, discard the first 3 mL effluent, and collect the subsequent effluent as the solution to be tested.

▶ Total boric acid and borate
(1) Weigh 1.0 g of the sample (accurate to 0.0001 g) in a 30 mL porcelain evaporating dish,
(2) Add 10 mL of sodium carbonate solution (3.9) and evaporate to dryness on a water bath.
(3) Transfer to the electric furnace for carbonization,
(4) Move into a high-temperature furnace and ash at 500 ℃ for 5 hours,
(5) After cooling, add 20 mL of hydrochloric acid solution to the ash to dissolve,
(6) Transfer to a 100 mL plastic volumetric flask, dilute to the mark with water, shake well,
(7) Pass through the Ag column and H column in sequence, discard the first 3 mL effluent, and collect the subsequent effluent as the solution to be tested.

4 Standard curve test

Standard curve series concentration gradient table(mg/L)
Name 1 2 3 4 5 6
Boric acid 2.00 5.00 20.00 50.00 100.00 200.00
Standard curve overlay chromatogram

5 Sample test

Sample blank test chromatogram

Note: There is no borate interference in the sample blank.

Overlapping chromatograms of parallel samples 1 and 2 of sample 1
Name Number Weighing amount (g) Constant volume (mL) Dilution times Determine the concentration (mg/L) content(%) Average content (%)
Boric acid Sample 1-Parallel Sample 1 1.0248 10 10 40.556 0.396 0.402
Sample 1-Parallel Sample 2 1.0392 42.443 0.408

Note: The absolute difference of the parallel determination results of the parallel samples does not exceed 10% deviation of the arithmetic mean, which meets the standard requirements.

6,Sample addition test

Overlapping chromatograms of sample 1 addition compared to the original sample
Name Number Weighing amount (g) Constant volume (mL) Dilution times Standard addition (mg) Concentration after standard addition (mg/L) Recovery rate(%)
Boric acid Sample 1-Parallel Sample 1 10 10 4.0 80.248 96.9
Sample 1-Parallel Sample 2 80.62 97.5

Note: The recovery rates of standard addition in this test are 96.9% and 97.5%, which meet the standard requirements.

7,Summarize

Using ion chromatography to detect borate in cosmetics, the pre-treatment is simple, and the target peak is peaked within ten minutes without other interference.

Category

News

View All