ANALISIS KUALITATIF DAN KUANTITATIF KANDUNGAN FORMALIN PADA PRODUK TERASI (Shrimp Paste) YANG DIPERDAGANGKAN DI PASAR SENTRAL KOTA DAN PASAR SENTRAL WUA-WUA

ABSTRACTThis study aimed to determine the formalin content of shrimp paste traded in the City Central Market and Wua-Wua Central Market. The analytical method used was the Phenylhydrazine method and quantitative test (Titration Method). The qualitative test was done to determine the presence or absence of formalin in the shrimp paste, while the quantitative test was done to determine the amount of formalin contained in the shrimp paste traded in the City Central Market and the Wua-Wua Central Market. This was a descriptive qualitative-quantitative study. The results of this study show that from 6 samples taken at the City Central Market and the Wua-Wua Central Market, five samples were positive for formalin. The average amount of formalin contents at the City Central Market were 77 mg/kg (A2) and 54.6 mg/kg (A3). Meanwhile, the average amount of formalin contents at the Wua-Wua Central Market were 60 mg/kg (B1), 66.7 mg/kg (B2), and 107.2 mg/kg (B3).Keywords: Shrimp paste, Formalin, Traditional marketABSTRAKPenelitian ini bertujuan untuk mengetahui kandungan formalin pada terasi yang diperdagangkan di Pasar Sentral Kota dan Pasar Sentral Wua-Wua. Metode analisis yang digunakan yaitu metode Fenilhidrazin dan uji kuantitatif (Metode Titrasi). Uji kualitatif bertujuan untuk mengetahui ada tidaknya formalin pada terasi, sedangkan uji kuantitatif bertujuan untuk mengetahui berapa kadar formalin yang terkandung pada terasi yang diperdagangkan di Pasar Sentral Kota dan Pasar Sentral Wua-Wua. Jenis penelitian ini yaitu deskriptif kualitatif dan kuantitatif. Hasil penelitian ini memberikan informasi bahwa sampel yang diambil dari 6 sampel Pasar Sentral Kota dan Pasar Sentral Wua-Wua 5 sampel positif mengandung formalin. Rata-rata persentase kadar formalin di lokasi Pasar Sentral Kota (A2) sebesar 77 mg/kg dan 54,6 mg/kg (A3). Pasar Sentral Wua-Wua (B1) 60 mg/kg, (B2) 66,7 mg/kg dan (B3) 107,2 mg/kg. Hasil penelitian menghasilkan simpulan terdeteksinya penggunaan formalin pada 5 sampel produk terasi yang beredar di lokasi Pasar Sentral Kota dan Pasar Sentral Wua-Wua kota Kendari.Kata kunci: Terasi, Formalin, Pasar tradisional.

Analysis of vitamin C in probiotic yoghurt with the addition of podang urang mango (Mangifera indica L.)

Yoghurt is a functional drink that is beneficial to health. However, nutritional losses, e.g. vitamin C, occurs during the thermal process. Therefore, vitamin C supplementation is needed to replace the lost amount during processing by adding the extract of podang urang mango (Mangifera indica L.). The yoghurt was made by adding 3% (v/v) of starter culture (Lactobacillus delbrueckii subsp bulgaricus RRAM-01 and Streptococcus salivarus subsp thermophillus RRAM-01) and mango extract at 0%, 2%, 4%, 6%, 8% and 10% (v/v) in four replications. The determination of vitamin C content was performed using titration method. The results showed that heating process at 85-90 °C in 35 minutes lowered the amount of vitamin C in the final product. However, the addition of podang urang mango extract at 6%, 8% and 10% could increase the amount of vitamin C.

Accurate Estimation of Bicarbonate and Acetic Acid Concentrations with Wider Ranges in Anaerobic Media Using Classical FOS/TAC Titration Method

The determination of a volatile fatty acid content (FOS) and total alkalinity (TAC) can be carried out using Nordmann’s FOS/TAC titration method developed in the 1970s. This two-point titration (pH = 5 and 4.4) can be simply implemented and is widely employed by both the academic and industrial worlds. However, the present study proves that Nordmann’s method is only valid in limited ranges, since the titration of one FOS and TAC has an impact on the determination of the other, especially in extreme conditions. The present work develops a numerical tool with Scilab simulating the acid–base equilibria of titration. The program is efficient in predicting the experimental equivalent volumes obtained from Nordmann’s method with different combinations of sodium acetate and sodium bicarbonate contents. The mean absolute percentage errors (MAPE) between the simulation and experiment are below 7%. Two new formulas are developed, considering both equivalent volumes at pH = 5 and 4.4 to calibrate FOS and TAC values. The proposed formulas show their good performance in predicting various combinations of FOS and TAC contents in an anaerobic digestate at TAC ranging from 0 to 20,000 mg CaCO3·L−1 and FOS ranging from 0 to 31,000 mg HAc·L−1.

Removal of rhodamine B from aqueous solution by adsorption on corn cobs activated carbon

<p>In the present study, adsorption experiments were carried out to investigate the removal of rhodamine B from an aqueous solution using chemically activated carbon from corn cobs, a cheaper adsorbent. The characteristics of carbon were determined using X-ray diffraction, SEM, iodine number, pHpzc, and the Boehm titration method. The results show that the prepared activated carbon is amorphous, microporous, and generally acidic on the surface. The kinetic study of the adsorption of rhodamine B on this carbon was carried out, and the rate of sorption was found to conform to pseudo-second-order kinetics with 80 min as equilibrium time. The equilibrium adsorption revealed that the experimental data fitted better to the Langmuir isotherm model for removing rhodamine B. The interaction rhodamine B-activated carbon is mainly chemisorption type. The optimal conditions of rhodamine B removal onto the carbon of this study are mass of carbon = 0.3 g and pH = 3.15. The maximum monolayer adsorption capacity for rhodamine B removal was found to be 5.92 mg.g^-1. This study has shown that the prepared activated carbon makes it possible to effectively clean up wastewater contaminated by rhodamine B with a removal efficiency of up to 99.60% for 300 mg of AC in 25 mL of the rhodamine B solution (5 mg.L^-1).</p>

Enhanced formaldehyde-removal over modified cryptomelane catalysts

M-OMS-2 materials (M = K+, Cu2+, Co2+) were prepared by an uncomplicated reflux method, and the cryptomelane crystalline structure was confirmed by X-ray diffraction patterns. Element analysis recorded ~56 - ~59 wt.% of Mn in the three synthesized samples and ~2.8 wt.% loadings of dopants over Co-OMS-2 and Cu-OMS-2 materials. A titration method valued the average oxidation states of manganese at 3.60, 3.71 and 3.77 for K-OMS-2, Co-OMS-2 and Cu-OMS-2, respectively. In comparison with K-OMS-2, Co and Cu dopants depicted a significant enhancement catalytic activity in removal of formaldehyde at low (5%) and high (65 %) relative humidity (RH). Cu-OMS-2 showed the highest catalyst performance with ~90 % of formaldehyde conversion at 150 °C, 65% RH, whereas only ~40 % (for Co-OMS-2) and ~26 % (for K-OMS-2) of that were observed. The finding results promised a potential Cu-OMS-2 material for designed low-costly catalyst in formaldehyde removal at a wide range of RH.

Comparative Quality Analysis between Tap Water and Bottled Water

Recently, bottled water consumption has been increasing significantly, even when the quality of tap water is considered excellent, which contributes to plastic pollution. Besides, reducing the use of plastic generally is recommended world widely, as its consumption is in an alarming rate. Therefore, this study aims to compare the tap and bottled water and manifest the reasons behind choosing the bottled water, which is less comfortable and often more expensive over the tap water. In this study, samples have been taken from both bottled and tap water in Koya city from November 2020 to May 2021 to test their quality using PH, DO, EC, and TDS meter, hardness was determined by complexometric titration method at 21°C, and XRF spectrometers. According to the quality standards, most of the variables were in a permissible range, except for dissolved oxygen and Aluminum content in both types of water and TDS for two types of bottled water. However, the quality of tap water was much safer to be used, as compared with the bottled water.

Measurement of Solubility of CO2 in NaCl, CaCl2, MgCl2 and MgCl2 + CaCl2 Brines at Temperatures from 298 to 373 K and Pressures up to 20 MPa Using the Potentiometric Titration Method

Understanding the carbon dioxide (CO2) solubility in formation brines is of great importance to several industrial applications, including CO2 sequestration and some CO2 capture technologies, as well as CO2-based enhanced hydrocarbon recovery methods. Despite years of study, there are few literature data on CO2 solubility for the low salinity range. Thus, in this study, the solubility of CO2 in distilled water and aqueous ionic solutions of NaCl, MgCl2, CaCl2 and MgCl2 + CaCl2 were obtained in a low salinity range (0–15,000 ppm) at temperatures from 298–373 K and pressures up to 20 MPa using an accurate and unconventional method called potentiometric titration. An experimental data set of 553 data points was collected using this method. The results of the experiments demonstrate that increasing pressure increases the solubility of CO2 in various brines, whereas increasing temperature and salinity reduces the solubility. The role of different ions in changing the solubility is elaborated through a detailed discussion on the salting-out effect of different ionic solutions. To verify the experimental results of this research, the solubility points obtained by the potentiometric titration method were compared to some of the well-established experimental and analytical data from the literature and a very good agreement with those was obtained.