Maeda J, Dudrick S J
Third Department of Surgery, University of Tokyo, Japan.
JPEN J Parenter Enteral Nutr. 1990 Sep-Oct;14(5):527-32. doi: 10.1177/0148607190014005527.
A spectrophotometric enzymatic assay for plasma carnitine concentrations has been automated on the Monarch 2000. Prior to the assay, each plasma sample was divided into three fractions, ie, free carnitine, acid-soluble carnitine and total carnitine, in order to determine the concentration of both free and esterified carnitine. Using the method developed by Tachikawa et al (Seikagaku 56:998, 1984), each of the samples was then chromatographed on an anion exchange resin to eliminate those compounds which could adversely impact the accuracy of the enzymatic assay for carnitine. After the completion of these preparatory steps, 32 specimens were assayed in less than 16 min on the Monarch 2000 with a high degree of both accuracy and precision. The assay was linear over a wide concentration range (5.0-80 mumol/liter), with the lower limit of sensitivity being 5.0 mumol/liter. The coefficient of variation (CV%) of the within run precision was 2.1%, 2.8%, and 6.7% for the determinations of free carnitine, acid-soluble carnitine, and total carnitine, and 17.4% and 27.8% for the calculated values of short-chain and long-chain acylcarnitines, respectively. The CV% of the between run precision for the same fractions was 6.5%, 2.7%, 3.8%, 14.2%, and 14.3%, respectively. When authentic L-carnitine was added to the plasma, the mean recovery rate was 94.7 +/- 11.0%. Reference values were determined using plasma obtained from 40 healthy adult volunteers.
一种用于测定血浆肉碱浓度的分光光度酶法已在Monarch 2000上实现自动化。在测定之前，将每个血浆样本分为三个部分，即游离肉碱、酸溶性肉碱和总肉碱，以确定游离和酯化肉碱的浓度。然后使用Tachikawa等人开发的方法（《生物化学》56:998，1984），将每个样本在阴离子交换树脂上进行色谱分离，以去除那些可能对肉碱酶法测定准确性产生不利影响的化合物。完成这些准备步骤后，在Monarch 2000上用不到16分钟的时间对32个样本进行了测定，准确性和精密度都很高。该测定在很宽的浓度范围内（5.0 - 80 μmol/升）呈线性，灵敏度下限为5.0 μmol/升。游离肉碱、酸溶性肉碱和总肉碱测定的批内精密度变异系数（CV%）分别为2.1%、2.8%和6.7%，短链和长链酰基肉碱计算值的CV%分别为17.4%和27.8%。相同部分的批间精密度CV%分别为6.5%、2.7%、3.8%、14.2%和14.3%。当向血浆中添加纯L-肉碱时，平均回收率为94.7 +/- 11.0%。参考值是使用从40名健康成年志愿者获得的血浆确定的。
