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Rapid on-site detection of nitrite （Instructions
for use of nitrite rapid measuring tube） 1. Scope of application: this rapid measuring tube is suitable for rapid identification
of nitrite and rapid determination of nitrite content in food or water.
Detection limit: 0.05mg/l. Linear range: 0.05 ~ 5.0 mg / L. 2. Rapid detection of nitrite in table
salt and rapid identification of table salt and nitrite: Take 1 flat spoon of table salt with a small spoon attached to
the bag, add it to the detection tube, add distilled water or purified water
to the 1ml scale, cover the cover, shake the solid part, and compare it with
the standard color plate after 10 minutes. The value on the color plate
multiplied by 10 is the content of nitrite in table salt, mg / kg. When the
sample appears blood red and precipitates or quickly fades to yellow, it can
be determined that the nitrite content is quite high, or the sample itself is
nitrite. 3. Liquid sample detection: directly add 1ml of clarified liquid sample into the detection
tube, cover the cover, shake and dissolve the reagent, compare it with the
standard color plate after 10 minutes, and find out the color scale that is
the same as the color of the solution in the detection tube. The value on the
color scale is the content of nitrite (calculated as NaNO2) in the
sample, mg / L. If the content of nitrite is calculated in nitrogen (n) (such
as drinking water or source water), read the value on the color scale and
divide it by 5. If the content of nitrite is calculated by nitrite (NO2
-) (such as mineral water, bottled purified drinking water, etc.), read the
value on the color scale and divide it by 3.28. 4. Detection of turbid sample: 1ml of milk and bean paddle can be directly added to the
detection tube, cover it, shake and dissolve the reagent, compare it with the
standard color plate after 10 minutes, and find out the color scale that is
the same as the color of the solution in the detection tube. The value on the
color scale multiplied by 2 is the approximate content of nitrite in the
sample, mg / L. 5. Detection of solid or semi-solid
samples: take 1.0g or 1.0ml to 10ml of uniformly crushed sample into the
colorimetric tube, add distilled water or deionized
water (purified water) to the scale, shake it sufficiently and place it. Take
1.0ml of supernatant (or supernatant obtained by filtration or centrifugation)
and add it into the detection tube, cover it, shake and dissolve the reagent,
and compare it with the standard color plate after 10 minutes. The value on
the color plate multiplied by 10 is the content of nitrite in the sample, mg
/ kg, L (calculated as NaNO2). If the test result exceeds the
maximum value on the color plate, it can be measured after quantitative
dilution and multiplied by the dilution multiple when calculating the result
(for example, take 1.0ml from 10ml colorimetric tube and transfer it to
another 10ml colorimetric tube, add water to the scale, and add 1.0ml from it
to the detection tube for determination. The test result multiplied by 100
(dilution multiple) is the content of nitrite in the sample. 6 precautions 6.1 when the nitrite
content is high, the reagent will turn yellow soon after it turns red. Dilute
the yellow solution and put it into another new rapid test tube, it will turn
red again, so as to distinguish between nitrite and edible salt. 6.2 when the color of
the sample after reaction is greater than the 2.00mg/l color scale of the standard
color plate, the sample shall be diluted and then measured, and the dilution
multiple shall be multiplied when calculating the result. 6.3 nitrite often exists
in domestic drinking water and should not be used as diluent
for determination. 6.4 the reagent shall be stored at room temperature and away
from light, and the validity period is 24 months. 亚硝酸盐的现场快速检测 方法编号：CDC-1061 1. 适用范围：本速测管适用于亚硝酸盐的快速辨别及食物或水中亚硝酸盐含量的快速测定。检出限：0.05mg/L。线性范围：0.05～5.0 mg/L。 2. 食盐中亚硝酸盐的快速检测及食盐与亚硝酸盐的快速鉴别：用袋内附带小勺取食盐1平勺，加入到检测管中，加入蒸馏水或纯净水至1ml刻度处，盖上盖，将固体部分摇溶，10分钟后与标准色板对比，该色板上的数值乘上10即为食盐中亚硝酸盐的含量mg/ kg，（国标规定食盐（精盐）中亚硝酸盐的限量卫生标准应≤2 mg/kg）。当样品出现血红色且有沉淀产生或很快退色变成黄色时，可判定亚硝酸盐含量相当高，或样品本身就是亚硝酸盐。 3. 液体样品检测：直接取澄清液体样品1ml加入到检测管中，盖上盖，将试剂摇溶，10分钟后与标准色板对比，找出与检测管中溶液颜色相同的色阶，该色阶上的数值即为样品中亚硝酸盐（以NaNO2计）的含量mg/L。如果亚硝酸盐的含量是以氮（N）为计算单位（如饮用水或水源水等），读取色阶上的数值后除以5即可。如果亚硝酸盐的含量是以亚硝酸根（NO2-）为计算单位（如矿泉水、瓶装饮用纯净水等），读取色阶上的数值后除以3.28即可。 4. 乳浊样品检测：牛乳及豆桨可直接取1ml加入到检测管中，盖上盖，将试剂摇溶，10分钟后与标准色板对比，找出与检测管中溶液颜色相同的色阶，该色阶上的数值乘以2即为样品中亚硝酸盐的近似含量mg/L。 5. 固体或半固体样品检测：取粉碎均匀的样品 部分食品、饮用水中亚硝酸盐的限量标准参考值（以NaNO2计）
以N-计： 生活饮用水
≤1mg/L（约为≤5mg/L NaNO2 ） 以NO2-计： 矿泉水≤0.1 mg/L （约为≤0.15mg/L NaNO2 ）；
包装饮用水以≤0.005 mg/L（约为≤0.008mg/L NaNO2 ） 6 注意事项 6.1亚硝酸盐含量较高时，试剂显红色后不久会变为黄色，将黄色溶液再稀释放入另一新的速测管中又会显出红色，由此区分是亚硝酸盐还是食用盐。 6.2当样品反应后的颜色大于标准色板2.00mg/L色阶时，应将样品稀释后再测，计算结果时乘上稀释倍数。 6.3生活饮用水中常有亚硝酸盐存在，不宜作为测定用稀释液。 6.4 试剂常温避光保存，有效期24个月。
图像1. 水中的亚硝酸盐
图像2.牛乳中的亚硝酸盐 |
