- 背景資料
亞硫酸鉀(Potassium Sulfite)、亞硫酸鈉(Sodium Sulfite)、亞硫酸鈉(無水)Sodium Sulfite (Anhydrous)、亞硫酸氫鈉(Sodium Bisulfite)、低亞硫酸鈉(Sodium Hydrosulfite)、偏亞硫酸氫鉀(Potassium Metabisulfite)、亞硫酸氫鉀(Potassium Bisulfite)、偏亞硫酸氫鈉(Sodium Metabisulfite)被歸類為「亞硫酸鹽類」之食品添加物,其類別為: (四) 漂白劑,亞硫酸鹽類具有殺菌的功效以及極強的還原力,故可將食品的著色物還原漂白,並可抑制氧化作用,防止酵素與非酵素褐變反應,因而具有漂白的作用。此外,亞硫酸鹽之限量標準,以產品中SO2殘留量為判斷依據。
依據衛生福利部於 2018 年 8 月 21 日正式發佈「食品過敏原標示規定」(衛授食字第1071302165號),使用亞硫酸鹽類或二氧化硫等,其終產品以二氧化硫殘留量計每公斤十毫克以上之製品,必須要有過敏原醒語標示方式。
- A. MANUAL ASSAY PROCEDURE:
- B. AUTO-ANALYSER ASSAY PROCEDURE:
- C. MICROPLATE ASSAY PROCEDURE:
- SAMPLE PREPARATION:
NOTE: Due to the characteristic instability of sulphite solutions, samples should be analysed as soon as possible after sample preparation.
1. Sample dilution.
The amount of sulphite present in the cuvette (i.e. in the 0.1 mL of sample being analysed) should range between 1 and 50 µg. The sample solution must therefore be diluted sufficiently to yield a concentration of sulphite between 10 and 500 mg/L.
2. General considerations.
(a) Liquid samples: clear, slightly coloured and approximately neutral, liquid samples can be used directly in the assay.
(b) Acidic samples: if > 0.1 mL of an acidic sample is to be used undiluted, the pH of the solution should be increased to approx. 8.0 using 2 M NaOH and the solution incubated at room temperature for 30 min.
(c) Carbon dioxide: samples containing carbon dioxide should be degassed by increasing the pH to approx. 8.0 with 2 M NaOH and gentle stirring, or by stirring with a glass rod.
(d) Strongly coloured samples: if used undiluted, strongly coloured samples should be treated by the addition of 0.2 g of polyvinylpolypyrollidone (PVPP)/10 mL of sample. Shake the tube vigorously for 5 min and then filter through Whatman No. 1 filter paper or centrifuge at 4,000 x g for 10 min.
(e) Solid samples: homogenise or crush solid samples in distilled water and filter if necessary.
(f) Samples containing fat: extract such samples with hot water at a temperature above the melting point of the fat, e.g. in a 100 mL volumetric flask at 60°C. Adjust to room temperature and fill the volumetric flask to the mark with distilled water. Store on ice or in a refrigerator for 15-30 min and then filter. Discard the first few mL of filtrate and use the clear supernatant (which may be slightly opalescent) for the assay.
(g) Samples containing protein: deproteinise samples containing protein by adding an equal volume of ice-cold 1 M perchloric acid with mixing. Filter or centrifuge at 1,500 g for 10 min and adjust the pH of the supernatant to approx. 8.0 with 1 M KOH. Use the supernatant in the assay after appropriate dilution.
商品特色
商品規格
- 商品規格
50 assays (manual) / 500 assays (microplate) / 588 assays (auto-analyser)
Bottle 1:
Buffer (28 mL; pH 8.0) plus sodium azide (0.02% w/v) as a preservative.
Stable for > 2 years at 4°C.
Bottle 2:
NADH. Freeze dried powder.
Stable for > 2 years below -10°C.
Bottle 3:
NADH peroxidase solution (1.1 mL).
Stable for > 2 years below -10°C.
Bottle 4:
Sulfite oxidase suspension (1.1 mL).
Stable for > 2 years at 4°C.
Bottle 5:
Sodium sulphite standard powder (~ 5 g).
Stable for > 5 years; store sealed at room temperature.