Determination of chloramphenicol in milk

• Published in: Хранение и переработка сельхозсырья (Российская Федерация) no. 5; pp. 31 - 34
• Main Authors: Shulyak, T.L, Korotchienko, N.F, Gerasimova, N.P., Mogilev State Univ. of Food (Belarus)
• Format: Publication
• Language: Russian
• Published: 2008
• Subjects: ANALISIS; ANALYSE; ANALYSIS; CHLORAMPHENICOL; CLORAMFENICOL; CONTAMINACION; CONTAMINATION; DRUGS; FEDERACION DE RUSIA; FEDERATION DE RUSSIE; http://www.fao.org/aos/agrovoc#c_2395; http://www.fao.org/aos/agrovoc#c_28317; http://www.fao.org/aos/agrovoc#c_33240; http://www.fao.org/aos/agrovoc#c_4826; http://www.fao.org/aos/agrovoc#c_49928; http://www.fao.org/aos/agrovoc#c_9817; LAIT; LECHE; MEDICAMENT; MEDICAMENTOS; MILK; RUSSIAN FEDERATION

An express method has been developed to determine chloramphenicol in milk using concentrated chlorohydric acid (CCA), zinc dust, sodium nitrite and alkaline solution of beta-naphthol. There is given proceeding chemical reaction and a schedule for determining microquantities of chloramphenicol in a milk sample. To increase the sensitivity of the developed method, a milk sample with a volume of 2 ml is added with zinc dust and 10 drops of CCA to recover chloramphenicol up to amino derivative, as well as casein coagulation. CCA is used to twice: at the recovery stage of chloramphenicol diazotization. Results reproducibility increases by using for diazotization amino derivative of chloramphenicol of a mixture of 10% solution of sodium nitrite and CCA in the ratio: 100:1 in a volume of 5 drops. A recovery reaction of microquantity of chloramphenicol contained in 2 ml milk takes 10 min: first 5 min – at room temperature, then at t +55-60 deg C – in a water bath. Holding the milk sample after adding 10% solution of sodium nitrite and CCA fir 2 min allows to obtain well-producible results. Filtration of the sample through a two-layered cheesecloth filter is necessary to determine protein precipitate and increase the brightne4ss of the staining resulted. The brightest staining the sample is observed when using 2% solution of alkaline naphthol in 40% solution of sodium hydroxide in an amount of 1 drop increasing the sensitivity of the method, as the sample is practically undiluted. Staining the milk sample is estimated after 30-60 s. this holding is sufficient for complete running the reaction of formation of nitrogen dye and stable red staining. With the concentration of chloramphenicol in milk 2.0, 5.0 and 7.5 microgram/ml samples are stained red or cherry red; 1.5 microgram/ml – red; 1.0 microgram/ml – yellow or creamy orange. The express method for determining the quantity of chloramphenicol in milk is easy to use, high sensitive well-reproducible