When purchasing fresh food, the appearance and luster of the food significantly impact our buying choices. Consequently, lighting and color additives are extensively employed. Relevant legal regulations expressly stipulate that the sale of fresh consumable agricultural products must not employ illumination or other facilities that conspicuously alter the authentic color and sensory attributes of the consumable agricultural products, in order to prevent misleading consumers’ perceptual cognition of the merchandise.
Regarding color additives, during the pre-treatment process of samples, due to the substantial incorporation of synthetic color additives in certain food products, the utilization of conventional Solid Phase Extraction (SPE) columns may result in sample overload, leading to incomplete recovery of pigments. Addressing this issue, Welch has specially developed dedicated SPE columns for synthetic color additives. Through the innovation of novel packing materials, the column capacity of SPE has been significantly enhanced, augmenting the retention capability for pigments. As a result, even when dealing with higher sample concentrations during the loading phase, the columns can effectively match the sample concentration, ensuring that synthetic color additives are not lost in the process.
Following testing, in accordance with the National Food Safety Standard—Standard for Uses of Food Additives, utilizing High Performance Liquid Chromatography (HPLC) as the analytical method, the employment of Moonshine Corporation’s dedicated SPE columns for synthetic color additives yielded consistent results across a variety of food products such as beverages, jellies, bread, and preserved fruits. The spike recovery experiments demonstrated recovery rates surpassing 80%, with Relative Standard Deviation (RSD) values lower than 5%. This method effectively fulfills the testing requirements of the majority of our clientele.
Product Features:
- Enhanced Column Capacity: Facilitating optimal compatibility with high-concentration sample loading.
- Effective Interference Removal: Capable of efficiently eliminating interfering substances in artificial colorant detection experiments.
- Consistent Recovery Rate: Demonstrates stable recovery rates with Relative Standard Deviation (RSD) below 5%, satisfying national standard requirements.
Extraction Procedure:
- Sample Pre-treatment
For preserved fruits: Weigh 5g of the sample and add 10mL of anhydrous ethanol-2% ammonia solution-water mixture (7+2+1). Heat using ultrasound, followed by low-temperature centrifugation for 5 minutes (4800r/min). Transfer the supernatant to a round-bottom flask and repeat the process until the extracted solution is colorless. Collect the supernatants in the round-bottom flask and rotary evaporate them at 40°C-60°C until no liquid droplets remain (removing anhydrous ethanol and ammonia). Adjust the pH to (3-4) using citric acid and proceed to purification.
- Purification Steps
SPE Column: Welch Welchrom® Dedicated Column for Synthetic Color Additives, Specification: 500mg/6mL.
Activation: Pass 5mL of methanol, 5mL of water, and 5mL of pH 6 water through the column, and discard the eluates.
Sample Loading: Load the entire volume of the solution to be purified onto the column, while ensuring controlled flow rate to prevent excessive speed.
Wash: Wash with 10mL of pH 4 water, followed by 20mL of methanol-formic acid (6+4) solution (adjust as needed based on the sample), and then 10mL of pH 7 water until neutral.
Elution: Initially elute with 5mL of 2% ammoniated methanol, followed by subsequent elution with 15% ammoniated methanol until colorless. Collect the eluates in an evaporating dish and evaporate at 80°C.
Sample Preparation: Dissolve the dried residue in 5mL of water, filter through a 0.45μm filter membrane, and retrieve the filtrate for analysis.
Chromatographic Conditions:
Column: Welch Ultisil®XB-C18, 4.6 × 250mm, 5μm.
Mobile Phase: A – 0.02 mol/L Acetic Acid Solution, B – Methanol (gradient as specified in Table 1).
Flow Rate: 1.0 mL/min.
Column Temperature: 30°C.
Injection Volume: 20μL.
Detection Wavelength: 245nm
Table 1: Gradient Elution Conditions
| Time (min) | 0.02 mM Acetic Acid Solution (%) | Methanol (%) |
| 0 | 95 | 5 |
| 10 | 80 | 20 |
| 18 | 20 | 80 |
| 25 | 20 | 80 |
| 25.1 | 95 | 5 |
Chromatographic Chart and Actual Sample Measurement Results
| Target Compound | Recovery 1 | Recovery 2 | Recovery 3 | Recovery 4 | Average Recovery | RSD |
| Lemon Yellow | 94.37% | 93.53% | 97.12% | 97.33% | 95.59% | 2.01% |
| New Red | 92.02% | 93.62% | 95.98% | 96.51% | 94.53% | 2.21% |
| Amaranth | 95.04% | 93.75% | 96.46% | 96.76% | 95.50% | 1.45% |
| Carmine | 95.53% | 93.56% | 96.69% | 96.99% | 95.69% | 1.62% |
| Sunset Yellow | 95.42% | 93.74% | 96.62% | 97.00% | 95.70% | 1.53% |
| Bright Blue | 93.22% | 92.83% | 96.13% | 97.04% | 94.81% | 2.21% |
Table 2: Fortified Preserved Fruit Sample Spike Recovery Data
Storage Conditions and Shelf Life
Store at room temperature. Under these conditions, the shelf life is 3 years.
Product Information
| Item Number | Name | Specification |
| 005PM-195-30 | Dedicated Column for Synthetic Color Additives | Welchrom® Dedicated Column for Synthetic Color Additives, 500mg/6mL, Pack of 30 |
| 005PM-196-30 | Dedicated Column for Synthetic Color Additives | Welchrom® Dedicated Column for Synthetic Color Additives, 1g/6mL, Pack of 30 |
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