以不同加熱方式的檢測方法評估食品中二氧化硫含量

Using Different Heating Methods to Evaluate SO_2 Content in Foods

林照琦(Chao-Chi Lin) ； 林展立(Chan-Li Lin) ； 楊富婷(Fu-Ting Yang) ； 黃聖婷(Sheng-Ting Huang) ； 張勝祺(Shenq-Chyi Chang) ； 蔡岳廷(Yueh-Ting Tsai)

《檢驗及品保雜誌》 4卷1期 (2015/02) Pp. 34-41

https://doi.org/10.6573/JTQA.201502_4(1).04

摘要

食品中二氧化硫檢測的公告方法步驟中加熱方式是使用本生燈火焰，本質上具有危險性，因此有些實驗室利用加熱包取代本生燈的方式進行加熱，為了瞭解此兩種加熱方式對二氧化硫的檢出是否有所差異，本研究以標準品（200 ppm亞硫酸納溶液）及添加200 ppm亞硫酸納溶液的查核樣品（無值蝦皮）檢測其回收率，結果顯示兩種加熱方法在標準品的回收為96.2~99.6%，而查核樣品（無值蝦皮）加熱包加熱10分鐘時回收率僅79.0%，比本生燈的回收率的86.9%相遠，加熱包加熱20分鐘後回收率為85.6%和本生燈加熱方式的回收率88.6%相近，因此加熱包可以替代本生燈進行加熱，但建議加熱時間需要延長至20分鐘。另外、利用標準品、查核樣品（無值蝦皮）和添加樣品（金針）測試在含有高及低濃度（200 ppm 和50 ppm）亞硫酸鈉溶液以本生燈火焰加熱檢測其回收率，結果發現均甚穩定及準確。又法規上並無規定本生燈火焰尖端與圓底燒瓶的距離，以標準品及查核樣品（無值蝦皮）測試0 cm、1～2 cm和5 cm距離對回收率的影響，數據顯示標準品在1～2 cm回收率為97.9~98.7%，0 cm和5 cm回收率均為89.4～95.0%，而查核樣品（無值蝦皮）1～2 cm回收率為86.9～88.6%，0 cm和5 cm回收率為79.6～85.3%。綜合上述，吾等認為：（i）二氧化硫檢測方法中的加熱方式可利用加熱包替代本生指進行加熱，但加熱時間需要延長至20分鐘；（ii）本生燈火焰尖端與圓底燒瓶的距離在1～2 cm時，不論是在標準品或查核樣品，其回收率都是最佳的。（iii）圓底燒瓶的受熱面積大小及檢體基質不同可影響二氧化硫回收率，導致檢出數據的誤差，檢驗人員須加以警覺。

關鍵字

加熱法 ； 食品中二氧化硫檢測

並列摘要

The heating method identified by the Bureau of Food and Drug Management, Ministry of Health and Welfare, Taiwan, in published materials as the official method for food SO_2 quantification consists of using a Bunsen burner. However, because the use of Bunsen burners can create a substantial danger, some laboratory workers use heating pads instead of Bunsen burners for heating during such tests. To determine whether these two heating methods will make any difference in SO_2 quantification, we used 200 ppm Na_2SO_4 solution as a tested standard material and added 200 ppm Na_2SO_4 solution to SO_2-free dried small shrimps as spiked checking specimens to determine their recovery rates. The results showed that the recovery rates achieved for standard material using these two methods ranged from 96.2~99.6%. However, the recovery rate of SO_2-free dried small shrimps was 79% when using a heating pad to treat the specimens for 10 minutes. This indicates a big difference when compared to the rate obtain ed by using a Bunsen burner (86.9%). However, when the treating time was extended to 20 minutes, the recovery rate for SO_2 in the checking specimen was 85.6%, which comes closer to the 88.6% obtained by using a Bunsen burner. Additionally, we tested the standard material, the aforementioned checking specimens (SO_2- free dried small shrimps) and another spiked specimen (tulip flowers) with both high (200 ppm) and low (50 ppm) concentration Na_2SO_4 solutions using a Bunsen burner with 20 minutes of heating time to determine their recovery rates. The results revealed that the recovery rates obtained for those three types of specimens were quite stable and accurate. It should also be noted that the published official method does not specify the distance to be maintained between the tip of the Bunsen burner flame and the round bottom of the flask. We therefore used standard material and checking specimens to determine any differences in recovery rates with distances of 0 cm, 1~2 cm, and 5 cm. The results indicated that the recovery rates for standard material ranged from 97.9~98.7% when distances of 1-2 cm were used, and from 89.4~95.0% for distances of 0 cm and 5 cm. For SO_2-free dried small shrimps, the recovery rate ranged from 86.9~88.6% when a distance of 1-2 cm was used, and from 79.6~85.3% for distances of 0 cm and 5 cm. Based on the above findings, we can reach the following conclusions: (i) SO_2 content can be detected by using a heating pad in the testing process, but the treating time should be extended to 20 minutes; and (ii) the recovery rate for either standard material or checking specimens will be optimal when the distance between the tip of the flame and the round bottom of the flask is 1~2 cm.

並列關鍵字

Heating method ； Food SO_2 quantification