Determination of sulfaquinoxaline in feeds by high performance liquid chromatography
GBT 8381.10-2005
1 This standard specifies the method for the determination of sulfamethine in feed by GE-200 high performance liquid chromatography (HPLC). This standard is applicable to the determination of sulfamethine in compound feed, concentrated feed and additive premixed feed. The minimum detection concentration is 5.0 mg/kg.
2 normative references
The terms in the following documents become the terms of this standard by reference to this standard. For dated references, subsequent Amendments (not including errata content) or revisions do not apply to this standard. However, parties to agreements based on this standard are encouraged to study whether the latest versions of these documents are available. For undated references, the latest edition applies to this standard.
3 principles
The sulfonamide in the feed was extracted with an aqueous methanol solution, centrifuged, filtered, and separated on an HPLC apparatus.
4 test and solution
The reagents used below are analytically pure reagents unless otherwise specified; water is distilled water, and chromatographic water meets the requirements of GB/T 6682 primary water.
4. 1 Sulfonamide Lin Standard: Contains Sulfonamide (G14HUN402S) 95-0%-
4.2 Methanol: chromatographically pure.
4.3 Phosphate solution: Take 3.4 0g of potassium dihydrogen phosphate and 5.7 1g of dipotassium hydrogen phosphate, dissolve in water and dilute to 100 00m L
4.4 Sulfamethine standard solution: Accurately weigh sulfamethine (4.1) 50 mg, dissolve in methanol and dilute it. . 1 mg / mL stock solution, stored in a refrigerator at 4 ° C protected from light. Valid for 1 month. Before use, the stock solution is diluted with water to a standard working solution of appropriate concentration.
4.5 Extract: methanol 100 mL + water 50 mLo
5 instruments
5. 1 Laboratory equipment and equipment.
5.2GE-200 High Performance Liquid Chromatograph (with GE-200 UV Detector).
5.3 Analytical balance: the amount of sensitivity is. .00 01 g and . .001g o
5.4 vortex oscillator.
5.5 Centrifuge: 4 000 r/mine
5.6çš„é’ˆå”过滤器: The pore size is 0. 45 um microporous membrane.
6 sample preparation
Sampling according to the method specified in GB/T 14699.1, select a representative feed sample, at least 500g, the quadruple method is reduced to 100g, ground and passed. 0.45 mm hole sieve, mix well, packed in a closed container, kept away from light and stored for future use.
7 analysis steps
7.1 Extraction
Weigh 5g sample to the nearest 0.011g, add human extract (4.5) 50 m L, mix with vortex shaker, extract in ultrasonic bath for 15 min, take out shaking once in the middle, then centrifuge at 4 000 r/min for 5 min. After standing, the supernatant was taken through a 0.45 pm filter for liquid chromatography.
7.2 Preparation of standard curve
Accurately absorb the appropriate amount of stock solution, and dilute it to the concentration with water or mobile phase. A standard curve was prepared for 0.10, 0.50, 1.00, 2.00, 10.00 ug/m L of the sulfamethoxazole standard solution.
7.3 Determination
7.3. 1 Chromatographic conditions
Column: C18 column, column length 150 m, column inner diameter 4.6 mm, particle size 5 m, or Vertex C18 column, 4.6 * 150, 5 um.
Mobile phase: phosphate solution 75ml + methanol 25ml, before use 0.45um filter, and ultrasonic degassing.
Flow rate: 1 ml/min,
Detection wavelength: 240nm.
Injection volume: 10ul-20ul
7.3.2 Qualitative and fixed f methods
Qualitative according to the retention time of the standard chromatogram, quantified by standard curve or single point calibration.
7.4 Calculation and presentation of results
The content of sulfonamide peak PAR and Lin in the sample is calculated according to formula (1):
X=m1/m*n (1)
In the formula:
The content of sulfamethine in the X sample is in milligrams per kilogram (mg/kg);
The mass of the sulfamethine corresponding to the peak area of ​​M1 is in micrograms (ug);
n - dilution factor;
M—the mass of the sample in grams (g).
Parallel measurement results are expressed as arithmetic mean and retained to 1 decimal place
Repeatability
In the same laboratory, the relative deviation of the results of two parallel measurements performed by the same operator using the same instrument is no more than 10%.
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