Penentuan Komposisi Bahan Bakar Nabati Dalam Bahan Bakar Minyak Campuran Menggunakan Metode Direct Counting C-14

ABSTRAK. Telah dilakukan penentuan komposisi bahan bakar nabati (BBN) dalam bahan bakar minyak campuran (BBMC) dengan metode direct counting C-14. Penentuan komposisi BBN dalam BBMC dilakukan dengan cara memipet 10 mL BBMC ke dalam vial gelas kemudian ditambahkan 10 mL larutan sintilator Ultima Gold F (UGF) ke dalamnya. Vial tersebut dikocok agar campuran menjadi homogen kemudian dicacah menggunakan LSC (Liquid Scintillation Counter) Elmer Perkin 2900TR selama 20 menit sebanyak 30 siklus. Hasil pencacahan ditampilkan dalam bentuk tSIE (transformed external standard spectrum) dan cpm (cacahan permenit). Hasil analisis memperlihatkan nilai cpm yang meningkat seiring kenaikan persentase BBN dalam BBMC. Nilai cpm terendah dan tertinggi untuk sampel bensin, avtur, dan solar berturut-turut adalah 14,2363 dan 62,0343, 10,664 dan 44,535, serta 9,410 dan 61,789. Terdapat korelasi kuat antara nilai tSIE dan nilai cpm pada bensin dan solar tapi tidak pada avtur. Hasil analisis terhadap sampel uji menunjukkan bahwa sampel tersebut berada di luar grafik deret sampel. Metode direct counting ini diharapkan dapat menjadi referensi dalam uji mutu BBMC.ABSTRACT. The composition of biofuel (BF) in mixed oil fuel (MOF) has been determined using the C-14 direct counting method. Determination of the composition of BF in MOF was carried out by pipetting 10 mL of BBMC into a glass vial and then adding 10 mL of Ultima Gold F (UGF) scintillator solution into it. The vial was shaken so that the mixture became homogeneous and then counted using the Elmer Perkin 2900TR LSC (Liquid Scintillation Counter) for 20 minutes for 30 cycles. The results of the counting are displayed in the form of tSIE (transformed external standard spectrum) and cpm (counts per minute). The results of the analysis show that the value of cpm increases with the increase in the percentage of BF in MOF. The lowest and highest cpm values for gasoline, avtur, and diesel samples were 14.2363 and 62.0343, 10.664 and 44.535, and 9.410 and 61.789, respectively. There is a strong correlation between tSIE and cpm values for gasoline and diesel but not for avtur. The results of the analysis of the test sample indicate that the sample is outside the sample series graph. This direct counting method is expected to be a reference in the BBMC quality test.

Analysis of NGS-Ministr as A New Detection Strategy Chromosomal Trisomy 16 of Fetal Materials in Miscarriages

Background: Although many technologies can identify chromosomal abnormalities, they can’t completely replace the advantages of short tandem repeat (STR) genotyping technology. The miniSTR typing based on next generation sequencing (NGS-miniSTR) with high throughput, accuracy and sensitivity has the potential to determine the trisomy and overcome the limitations of conventional STR techniques, which never be tried. The study aimed to explore the value of the NGS-miniSTR in trisomy testing, which is an extension and improvement of the methodology of chromosomal detection technology.Methods: A total of 140 fetal materials in miscarriages (70 trisomy 16 and 70 normal karyotypes) screened by copy-number variation sequencing (CNV-seq) were genotyped using the customed panel containing 11 miniSTRs based on NGS. Direct counting method, chi-square (χ2) test, k-means clustering analysis and Mahalanobis distance were operated to compare the difference of miniSTR between trisomy 16 and normal group, and then analyze whether trisomy 16 could be identified.Results: All miniSTR results based on NGS were successfully obtained, except for D16S771 in 21 samples. There were significant differences in the average depth of coverage at each locus in each sample. Direct counting method and chi-square (χ2) test showed significant differences in allelic pattern and read ratio between trisomy and normal group, respectively. Almost all samples correctly divided into 2 clusters based on diallelic STR reads ratios according to k-means clustering analysis. In addition, the Mahalanobis distance showed that D16S771 had multiple outliers. Conclusion: A new strategy of miniSTR-NGS was firstly introduced to successfully detect all samples of trisomy 16 in the fetal material in miscarriages, which revealed that the allelic pattern and allelic read ratio could be effective indexes to identify the number of chromosomes.