Education And Language

Development Of Laboratory Work Instruction For Junior High School: Borax Content Identification Using Natural Indicators

Nanang Rahman, Agus Abhi Purwoko, Muntari,
Article Date Published : 3 May 2019 | Page No.: EL-2019-999-1005 | Google Scholar

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Abstract

The main goal of this study is to develop a laboratory work instruction for junior high school, in particular in identification of non food additives, such as borax, in daily foodstuff. The method of development is referred to a four-step procedure by Borg and Galls. There are 94 samples of extract of leafs and flowers of various tropical plants that have been examined for identification of borax. Of these samples it is found that there are 4 flower extracts that indicate sensitivity to the borax content, namely Ruellia Simplex, Curcuma Longa, Plumeria Ruba, and Portulaca Grandiflora. In later stage of development the laboratory instruction were validated by academic experts and school teachers. The results of validation indicate that the guideline is suitable to be implement in laboratory works at junior high school.

Keywords: laboratory work, borax test, natural indicator

Introduction

Indonesia is currently still using borax for food. Borax is often used as an additional snack ingredient. One report shows that the borax concentration up to 136 g/kg of wet noodle, a foodstuff that is commonly sold in traditional market, is found in Manado city Indonesia (Payu, 2016). Consuming foodstuff that contains a small amount of borax is not considered fatal, but the accumulation in body due to prolong consumption of contaminated foods will cause poisoning2 .

Doses of 200-640 mg boric acid / kg have been reported to be lethal, but the number has not been fully verified 3 . Another report states that the lowest deadly dose after accidental swallowing of boric acid by humans ranges from about 98 to 650 mg boron/kg body weight4 . Death has been reported when boron is administered intravenously at 0.5 mg boron / kg body weight 5

There are several methods that have been used to test the presence of borax. 6 developed a method for testing boric acid with glycerine, then titrated with potassium hydroxide. There are three methods known for determining detailed boric acid in food, namely the titrimetric method using mannitol, and two colorimetric procedures using carminic acid or curcumin. Colorimetric procedures with the curcumin method is found to be the most reliable and therefore will be the method of choice for the determination of boric acid in food7 . Another method is fast quantitative analysis of boric acid by gas chromatography - mass spectrometry coupled with a simple and selective derivatization reaction using triethanolamine 8 .

The methods for testing borax described above are expensive and they are less feasible for classroom instruction, in particular to be implemented for junior high school. Alternative methods should be developed using simple, low cost, and accessible procedures (Nanang, 2018). In science learning it is suggested that direct reflective methods should be used rather than indirectly for students to understand the true nature of science 10 . Direct reflective methods can be done through laboratory activities. This study aims to develop a laboratory work instruction for borax tests that is simple and easy to use in classroom instruction for junior high school students. The mentioned method uses natural indicators extracted from plants that are found locally. The procedure can be carried out in a simple and fast way for the purpose of qualitative testing

Method

The procedure used in this kind of research is procedural development where the steps are explained in a concrete and detailed manner. The development procedure carried out refers to the one developed by Borg & Galls (1996). Borg and Gall found that the development research procedure basically consisted of two main objectives, namely developing products and validating the products so produced. The description of this development model is explained in Figure 1.

Figure 1:

Details of the research procedures that have been carried out are as follows:

          The step of the borax test practicum with natural indicators is then compiled in practical instructions that can be used by junior high school students.

              The instrument used in this study is a questionnaire on the feasibility of products that have been developed. Preliminary Field testing is given a questionnaire to chemists and science education experts. Main field testing was given a questionnaire to 8 teachers in several schools in the province of West Nusa Tenggara. The questionnaire used contains 3 aspects of assessment: disability, graphics and practicality of use. Readability aspect: the instructions for using the borax test practicum book with natural indicators are easy to understand, the statements and sentences in the borax test instruction with natural indicators are easy to understand, the size and model of the letters used in the borax test instruction are clearly visible and easy to use. Graphical aspect: the drawings on the borax test instruction with natural indicators look attractive and clear, the cover in the borax instruction with natural indicators looks attractive. Practical aspects of use: the use of borax test practicum instructions with natural indicators is easy to use, the use of time is more effective when practicum with practical instructions borax test with natural indicators, the information provided in the borax practicum instructions with natural indicators makes practicum more active, creative, and fun, the procedures and work steps are presented in a clear and easy to use.

                Feasibility questionnaire for device products borax test is provided to experts and teachers. The data obtained from the questionnaire were changed to interval data. The questionnaire provided contains five choices to provide feedback about the practicum instruction products that have been developed, namely: very good (5), good (4), good enough (3), not good (2) and very poor (1). If the respondent gives a "very good" response then the statement item is given the number "5" and so does the other. The score obtained is then converted to a value on a scale of 5 with a table reference quoted from Saifuddin Azwar (2010), as follows:

                Score Interval Value Categori
                X > x i + 1,5 SB i A Very good
                x i + 0,5 SB i < X x i + 1,5 SB i B Good
                x i - 0,5 SB i < X x i + 0,5 SB i C Good enough
                x i - 1,5 SB i < X x i – 0,5 SB i D Not good
                X x i - 1,5 SB i E Very poor

                Conversion of Actual Scores to Five-Scale Values

                Information:

                xi = Average ideal score = 1/2 (ideal maximum score + ideal minimum score) SBi = Ideal standard deviation = 1/6 (ideal maximum score - ideal minimum score) X = Actual score (score achieved) Ideal maximum score = Σ item criterion x highest score Ideal lowest score = Σ item criterion x lowest score

                Result and Discussion

                Early identification of plants that are used as a natural indicator to test borax is those that have a bright color, because the color of the borax solution is colorless (transparent). There are two parts of the plant that are used as the test material, namely leaves and flower crowns. Based on the field observations that had been carried out on plants in the West Nusa Tenggara Province, 94 leaf and flower crown samples were taken which were believed to have potential use as natural indicators for borax test.

                Based on the results of the trial of 0.1 M borax solution using various plant extracts that have been identified, 4 samples of extracts give positive reaction, namely: Ruella Simplex, Curcuma Longa, Plumeria Rubca, and Portulaca Grandiflora. The following are the results of the 0, 1 M borax trial with these 4 types of indicators.

                After finding natural indicators that can be used for borax testing, a practical guide will be developed that be used by junior high school students. Cover and contents of the practicum instructions that have been developed as follows.

                The laboratory work instruction that have been developed are validated by experts and by request responses from teachers with questionnaire instruments. The following are the results of the expert validation questionnaire and teacher respons

                Assesment aspect Average rating
                Expert Teacher Average
                Readability 12.50 13.20 12.85
                Graphics 7.50 7.60 7.55
                Practicality of use 23.00 23.50 23.25

                Average results of expert validation and assessment of 8 teachers

                Based on the results of questionnaires that have been given to experts and teachers there are several inputs related to the practicum instructions that have been produced: (1)The image of the flower for the indicator is made clearer in color. Impatia balsamia flower images used in practicum manuals have low image resolution so that they are not clearly visible, (2) Larger image size to make it clear. The image displayed in the practicum manual is too small so that the type of flower is not clear enough to be used to test borax, (3) Filter paper as an indicator made smaller in size to make it easier to use. Initially the indicator paper from filter paper made was 1 x 7 cm in size, but based on expert input suggested that the indicator paper size be reduced to 0.5 x 5 cm.

                3.2 Discussion

                In general, the color of flowers is caused by flavonoid and carotenoid pigments which can attract attention to help pollination. Flavonoids are the most common flower color pigment, and the dominant flavonoid pigments are anthocyanins. Anthocyanins are composed of anthocyanidin and sugar groups. They are the basis for most of the colors orange, pink, red, magenta, purple, blue, and blue-black. Common anthocyanidins are pelargonidin, cyanidin, peonidin, delphinidin, petunidin, and malvinidin, named after the genera from which they were first isolated. Most anthocyanins come from only the following three basic anthocyanidins: pelargonidin, cyanidin, and delphinidin (Davies, 2009).

                The first natural indicator that is used as extract to identify borax is the ruellia simplex. The dyestuffs contained in ruellia simplex with purple color are anthocyanins 14 . Anthocyanins are a bioactive component of the flavonoid group found in flowers, leaves, yams, fruits and vegetables clinging to the pH of the environment in which they are located 15 16 . The structure of anthocyanins changes at pH 1, pH 4.5 and pH 717 . Changes in pH cause changes in the structure of the quinonoidalanidrobase pH 6.5-8 to cis-chalcone pH > 9 (Marco et al. 2011). Borax solution which has a pH of around 9.5 when added drop wise to the extract of Ruellia simplex that shows purple color will experience a blue-green color change due to structural changes. Structural changes cause complement color changes that can be observed as an indicator to determine the presence of borax in a sample.

                The second natural indicator used to identify borax is turmeric. Turmeric contains the main ingredient of yellow color known as curcumin (Anderson et al. 2005). Curcumin (1,7-Bis- (4-hydroxy-3methoxyphenyl) -hepta-1,6-diene-3,5-dione) is an oil-soluble pigment, practically insoluble in water at acidic and neutral pH, soluble in alkali and very vulnerable form of pH change20 . However, in an aqueous system such as water, it can be understood that at alkaline pH, the phenol group acid in curcumin donates hydrogen, forming phenolic ions which allow curcumin to dissolve in water. This form is not stable at neutral and alkaline pH for a longer period of time and easily degrades into compounds such as vanillin, ferulic acid, etc. This form is stable at a pH below 7.0 but with a decrease in pH value, shifting the dissociation equilibrium to a neutral form with very low water solubility21 . The curcumin obtained from turmeric can be used to decompose the borax bond into boric acid and bind it into a rosa color complex or commonly called the complex boron cyanocurcumin compound which is a red colored substance. The color change from yellow to reddish on turmeric can be used as a natural indicator material to detect the presence of borax in laboratory activities.

                The third flower that can be used as a natural indicator material is the Plumeriarubra flower. Anthocyanins cause red to blue color in plants (Andersen & Jordheim, 2005). The color changes that occur in plumeriarubra extract after being mixed with borax solution caused by changes in the structure of anthocyanins at pH 9.5 as in the ruellia simplex flower.

                The fourth indicator that can be used to identify borax is the flower of Portulaca Grandiflora which is an ordo of Caryophyllales plants. Betalain is a pigment that replaces anthocyanins in most families of the Caryophyllales plant ordo22 . In food processing, betalain is less commonly used than anthocyanins and carotenoids, although this water-soluble pigment, stable between pH 3 and 7, is suitable for coloring low-acid foods23 24 25 . If Portulaca Grandiflora is mixed with borax solution which has a pH of 9.5, it will change the structure of the betalain so that the color will change from pink to red purple. This color change justifies the use of Portulaca Grandiflora to be a natural indicator to identify the presence of borax.

                Using Table 1 as reference then the validation results and the teacher's response to the practicum instructions are then converted to a five scale. Following are the results of conversion scores for readability, graphs and practicality of use.

                Aspect Interval Value Category
                Readability X > 12.0 A Very good
                10.0 < X ≤ 12.0 B Good
                8.0 < X ≤ 10.0 C Fair
                6.0 < X ≤ 8.0 D Poor
                X ≤ 6.0 E Very poor
                Graphics X > 8.0 A Very good
                6.6 < X ≤ 8.0 B Good
                5.4 < X ≤ 6.6 C Fair
                4.0 < X ≤ 5.4 D Poor
                X ≤ 4.0 E Very poor
                Practicality of use X >20.0 A Very good
                16.6< X ≤ 20.0 B Good
                13.3< X ≤ 16.6 C Fair
                10.0< X ≤ 13.3 D Poor
                X ≤ 10.0 E Very poor

                The results of the conversion of scores to a scale of five

                The results of expert validation and teacher assessment in table 3 compared with table 4, about the quality of borax test practice guidelines using indicators of Ruellia Simplex, Curcuma Longa, Plumeria Rubra, and Portulaca Grandiflora. Conclusion of the results of the assessment of practicum instructions as follows.

                Assesment aspect Average rating
                Average value Interval Category
                Readability 12.85 X > 12.0 Very good
                Graphics 7.55 6.6 < X ≤ 8.0 Good
                Practicality of use 23.25 X > 20.0 Very good

                Conclusions on the results of assessment of practicum instructions

                Based on the results of expert validation and teacher's assessment of the borax test practicum instructions using the Ruellia Simplex, Curcuma Longa, Plumeria Rubra, and Portulaca Grandiflora in table 5, it was concluded that the readability value of X > 12 was in the very good category, graphical aspects value 6.6 < X ≤ 8.0 in good category and practicality of use aspects X > 20.0 in very good categories.

                Conclusion

                The results of this study indicate that the laboratory work instruction of determining borax’s content qualitatively for junior high school students could make use of natural indicator drops test of flower the Ruellia simplex, Curcuma longa, Plumeria rubra, and Portulaca grandiflora. Identification using filter paper that has contained natural indicator plant extracts can also be used for borax testing. Based on expert judgment and the teacher’s response show that practicum instructions that have been developed is suitable for use

                Acknowledgements

                This research is a collaborative research between University of Muhammadiyah Mataram and University of Mataram. This research is fully funded by the Ministry of Research, Technology and Higher Education Republic of Indonesia.

                References

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                International Journal of Scientific Research and Management, 2019.
                Creative Commons License

                This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.

                Article Details


                Issue: Vol 7 No 05 (2019)
                Page No.: EL-2019-999-1005
                Section: Education And Language
                DOI: https://doi.org/10.18535/ijsrm/v7i5.el01

                How to Cite

                Rahman, N., Abhi Purwoko, A., & Muntari. (2019). Development Of Laboratory Work Instruction For Junior High School: Borax Content Identification Using Natural Indicators. International Journal of Scientific Research and Management, 7(05), EL-2019. https://doi.org/10.18535/ijsrm/v7i5.el01

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