Influence of mixing parameters in STAR automatic sample processing instruments on the detection results of internal controls / 中国输血杂志

【Objective】 To explore the significance of blending internal controls by automatic sample processing instruments in the enzyme linked immunosorbent assay (ELISA). 【Methods】 The internal controls were vortexed and mixed before the test, and then were added to the same ELISA plate by the STAR automatic sample processing instruments under the same detection conditions. The difference of S/CO value of internal controls with and without sufficient blending via the sampling needle and their frequency distribution were compared. Internal controls that were greatly affected by mixing parameters were submitted to the same test with different batches of reagents from the same manufacturer, and the results were analyzed for consistency. 【Results】 The S/CO value of anti-HCV internal controls without blending using adding sample needle was significantly lower than that of quality control samples with sufficient blending (P<0.000 1). The S/CO values of unmixed internal controls concerning anti-TP and anti-HIV detection given by some detection systems were also different from the values of mixed internal controls (P<0.05). Some of the S/CO values of the anti-HCV internal controls without mixing were distributed within the interval of less than 2. Different batches of reagents from the same manufacturer were used to detect anti-HCV internal controls, and there were differences in the partial detection values between the mixed and unmixed internal controls (P<0.05). 【Conclusion】 Although the internal controls were mixed by vortex shock before the test, the detection results of some internal controls will still be affected when the STAR automatic sample processing instruments does not set the mixing parameters for internal controls.

Incertidumbre drrante el procesamiento de fruta y hortalizas en el análisis dee residuos de plaguiciaas / Uncertaity durinng sample processing of fruits and vegetbles in pesticiide residue analysis

En este estudio se determinó la incertidumbre durante el procesamiento de la muestra u homogeneización de diferentes matrices (tomate, lechuga y naranja), a temperatura ambiente y con hielo seco. El método se basó en la estimación de las constantes de muestreo y en la utilización de un compuesto de referencia (14C-clorpirifos). Para ello fue necesario desarrollar 5 experimentos por cada matriz y tipo de homogeneización. Realizada la homogeneización, se tomaron 5 réplicas de (porciones analíticas) por experimento. Para cada una de las porciones analíticas se calculó su varianza y se evaluó estadísticamente si no existía diferencia significativa entre ellas. Cuando no existió diferencia significativa entre las dos varianzas se calculó el coeficiente de variación para la porción de mayor tamaño. A partir de este CV y el peso de la porción analítica de 150 g, se calculó la constante de muestreo. Obtenida la constante de muestreo, se pudo determinar la incertidumbre para cualquier porción analítica. La incertidumbre en la homogeneización con hielo seco de todas las muestras no fue significativamente diferente entre sí, porque fue reproducible sin importar la matriz, mientras que la homogeneización a temperatura ambiente demostró diferencias significativas en el procesamiento cuando se cambia el tipo de muestra. En cada matriz se demostró que no existe diferencia significativa entre la homogeneización a temperatura ambiente y la realizada con hielo seco. Se determinó que la incertidumbre de la extracción, comparada con la incertidumbre durante el procesamiento de la muestra, fue despreciable para todas las matrices; por tanto, la incertidumbre durante la homogeneización pudo determinarse directamente de los experimentos.

In this study, the uncertainty during sample processing or homogenization of several different matrices (tomato, lettuce and orange) was determined at ambient temperature and with dry ice. The method was based on surface treatment of the matrix with a reference compound (14C-chlorpyrifos) and estimation of the sampling constants. The uncertainty determination was carried out developing 5 experiments for each of the different homogenizations and matrices. After homogenization, 5 replicate analytical portions of 15 g and 150 g were withdrawn for each experiment. The variance was calculated for each analytical portion. The significant difference between the variance of smaller analytical portion and the variance of larger analytical portion was evaluated. Then the coefficient of variation (CV) was calculated for the larger portion. This coefficient was used to calculate the sampling constant. Then, the uncertainty could be determined for any analytical portion size. The sample processing uncertainty obtained with dry ice for all samples was not significantly different. There was no any significant difference between homogenization at ambient temperature and homogenization with dry ice for each matrix. The extraction uncertainty was negligible for all matrices compared to the sample processing component. It allows one to quantify the sample processing uncertainty directly.

Signifioant Influence of Sample Processing on the Assay of Adenine Nucleotides, Lactate and Pyruvate in Rat Muscle / 昆明医科大学学报

An ideal assay of adenine nucleotides, lactate and pyruvate in the extract of rat freeze-clamped muscle was achieved. Electromicroscopy showed that the cell membrane was destroyed by powdering the muscle in liquid N_2 and then homogenizing for 1 min. An additien of ultrasonic treatment for 1 min could thoroughly break the subcellular structures and lead to a remarkable increase in ATP and total adenine nucleotides with a little change of lactate and pyruvate. The prolongation of the treatment for two more minutes, however, could result in the breakdown of ATP.