An accurate, precise, and affordable light emitting diode spectrophotometer for drinking water and other testing with limited resources

Michael W. Prairie; Seth H. Frisbie; K. Kesava Rao; Anyamanee H. Saksri; Shreyas Parbat; Erika J. Mitchell

doi:10.1371/journal.pone.0226761

Peer Review History

Original SubmissionJune 25, 2019
16 Oct 2019 Decision Letter - Talib Al-Ameri, Editor PONE-D-19-17629 An accurate, precise, and affordable light emitting diode spectrophotometer for drinking water and other testing with limited resources PLOS ONE Dear Frisbie, Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process. We would appreciate receiving your revised manuscript by Nov 30 2019 11:59PM. When you are ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file. If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. To enhance the reproducibility of your results, we recommend that if applicable you deposit your laboratory protocols in protocols.io, where a protocol can be assigned its own identifier (DOI) such that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols Please include the following items when submitting your revised manuscript: A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). This letter should be uploaded as separate file and labeled 'Response to Reviewers'. A marked-up copy of your manuscript that highlights changes made to the original version. This file should be uploaded as separate file and labeled 'Revised Manuscript with Track Changes'. An unmarked version of your revised paper without tracked changes. This file should be uploaded as separate file and labeled 'Manuscript'. Please note while forming your response, if your article is accepted, you may have the opportunity to make the peer review history publicly available. The record will include editor decision letters (with reviews) and your responses to reviewer comments. If eligible, we will contact you to opt in or out. We look forward to receiving your revised manuscript. Kind regards, Talib Al-Ameri, Ph.D Academic Editor PLOS ONE Journal Requirements: 1. When submitting your revision, we need you to address these additional requirements. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at http://www.journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and http://www.journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf 2. Thank you for stating the following in the Acknowledgments Section of your manuscript: This study was supported by Norwich University, and the Indian Institute of Science. We note that you have provided funding information that is not currently declared in your Funding Statement. However, funding information should not appear in the Acknowledgments section or other areas of your manuscript. We will only publish funding information present in the Funding Statement section of the online submission form. Please remove any funding-related text from the manuscript and let us know how you would like to update your Funding Statement. Currently, your Funding Statement reads as follows: The authors received no specific funding for this work. [Note: HTML markup is below. Please do not edit.] Reviewers' comments: Reviewer's Responses to Questions Comments to the Author 1. Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented. Reviewer #1: Yes Reviewer #2: No ******** 2. Has the statistical analysis been performed appropriately and rigorously? Reviewer #1: Yes Reviewer #2: No ****** 3. Have the authors made all data underlying the findings in their manuscript fully available? The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified. Reviewer #1: Yes Reviewer #2: No ****** 4. Is the manuscript presented in an intelligible fashion and written in standard English? PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here. Reviewer #1: Yes Reviewer #2: No ****** 5. Review Comments to the Author Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters) Reviewer #1: This manuscript describes the design and performance of an accurate and precise light emitting diode (LED) Spectrophotometer that costs approximately 63 U.S. dollars for parts, less than 2.6% of the cost of several commercial Spectrophotometers. The paper is well organized and clearly written. The technical quality of the manuscript is satisfactory but the length is too long in relation to technical impact. Although reducing of equipment’s cost is not novel in most cases, this study considered as a valuable longitudinal study since the LED Spectrophotometer was continuously designed, tested, and improved over a three-year period. I would recommend publish this this manuscript after minor corrections. Most regions of limited resources suffer from lack of availability of most components and that may affect the prices. I would recommend authors to consider this point in the motivation (in my knowledge these components are cheap in the industrial countries while the cost may be higher in regions of limited resources). Secondly, I would suggest authors to involve statistical variability in the analysis (optional or in the future work). Reviewer #2: In this paper, a light emitting diode spectrophotometer was designed and implemented for drinking water and other testing with limited resources. However, I recommend rejecting the paper for the following reasons. 1. The novelty of the paper is not well presented. 2. The contributions in the fields of study wholly missing. 3. The paper is not well structured and organized. 4. More unnecessarily information and details were presented in the paper. 5. The introduction section is very poor and did not highlight the problem statement in the field of study. In addition, the previous solutions in this field were not discussed or investigated in the study. 6. The related works section is missing. 7. The study presents well-known information, not new for specialists. 8. The “power unit and Light-emitting diode source circuit” they have been explained in detail though it is a simple electronic circuit. 9. Equation (11), this equation is well known for the standard deviation. Why the authors named it "precision standard". 10. Table 1 is not necessary to present the price of the components, instead, the authors can present the specifications of the proposed design. 11. Statistical analyses were not presented in a good manner. 12. The linear regression (R2) must be presented as a figure to allow the reader to seen the improvement in correlation between proposed LED spectrophotometer and commercial spectrophotometer. 13. The limits of agreement, better if it is measured under the Bland-Altman test. Where, the Bland-Altman test shows the upper and lower of agreement, difference of mean, standard deviation of difference. The difference here refers to the difference in measurement between proposed LED spectrophotometer and commercial spectrophotometer. 14. The resolution of Figs. 7-13. 15. The journal references are out of date. 16. Overall evolution, the paper is not well presented and organized, the contribution is missing, and the novelty is not clear. So, I recommend rejecting the paper for publication in a PLOS ONE Journal. ****** 6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files. If you choose “no”, your identity will remain anonymous but your review may still be made public. Do you want your identity to be public for this peer review?** For information about this choice, including consent withdrawal, please see our Privacy Policy. Reviewer #1: No Reviewer #2: No [NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files to be viewed.] While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email us at figures@plos.org. Please note that Supporting Information files do not need this step. https://doi.org/10.1371/journal.pone.0226761.r001
Revision 1
29 Nov 2019 Author Response Dear Dr. Al-Ameri, Thank you for reviewing our manuscript: PONE-D-19-17629 An accurate, precise, and affordable light emitting diode spectrophotometer for drinking water and other testing with limited resources We greatly appreciate the comments that you and the anonymous reviewers have made. These suggestions have proved very helpful in our revisions to the manuscript. We have addressed each of the reviewers’ comments, either through revisions to the manuscript, or provided further explanations in our rebuttal, as detailed below. As we revised this paper, we enlisted the assistance of an additional author, Dr. Erika J. Mitchell of Better Life Laboratories. Dr. Mitchell assisted us with updating the statistical analyses, the Bland-Altman plots, expanding the literature review, drafting portions of the revised introduction, and editing the paper. Accordingly, we would like to add her as an author to this manuscript. Thank you again for your consideration of this manuscript, Seth H. Frisbie, Ph.D. Associate Professor of Chemistry Department of Chemistry and Biochemistry 201 Juckett Hall Norwich University Northfield, VT 05663 Telephone: 1-802-485-2614 Fax: 1-802-485-2333 E-mail: sfrisbie@norwich.edu PLOS ONE Decision: Revision required [PONE-D-19-17629] - [EMID:beb0e08c96cd9025] em.pone.0.66a152.ac1b58a4@editorialmanager.com on behalf of PLOS ONE <em@editorialmanager.com> Wed 10/16/2019 4:59 AM PONE-D-19-17629 An accurate, precise, and affordable light emitting diode spectrophotometer for drinking water and other testing with limited resources PLOS ONE Dear Frisbie, Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process. We would appreciate receiving your revised manuscript by Nov 30 2019 11:59PM. When you are ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file. If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. To enhance the reproducibility of your results, we recommend that if applicable you deposit your laboratory protocols in protocols.io, where a protocol can be assigned its own identifier (DOI) such that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols Please include the following items when submitting your revised manuscript: • A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). This letter should be uploaded as separate file and labeled 'Response to Reviewers'. • A marked-up copy of your manuscript that highlights changes made to the original version. This file should be uploaded as separate file and labeled 'Revised Manuscript with Track Changes'. • An unmarked version of your revised paper without tracked changes. This file should be uploaded as separate file and labeled 'Manuscript'. Please note while forming your response, if your article is accepted, you may have the opportunity to make the peer review history publicly available. The record will include editor decision letters (with reviews) and your responses to reviewer comments. If eligible, we will contact you to opt in or out. We look forward to receiving your revised manuscript. Kind regards, Talib Al-Ameri, Ph.D Academic Editor PLOS ONE Journal Requirements: 1. When submitting your revision, we need you to address these additional requirements. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at http://www.journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and http://www.journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf 2. Thank you for stating the following in the Acknowledgments Section of your manuscript: This study was supported by Norwich University, and the Indian Institute of Science. We note that you have provided funding information that is not currently declared in your Funding Statement. However, funding information should not appear in the Acknowledgments section or other areas of your manuscript. We will only publish funding information present in the Funding Statement section of the online submission form. Please remove any funding-related text from the manuscript and let us know how you would like to update your Funding Statement. REVISION MADE: We have removed the funding-related text from the Acknowledgments section. Please revise the Funding Statement for us since we cannot revise it from the document submission system. Please update the Funding Statement to read: The authors received no specific funding for this work. Non-specific support was provided by Norwich University and the Ministry of Human Resource Development, Government of India. EJM’s affiliation is with Better Life Laboratories, a nonprofit organization that conducts scientific research and provides technical expertise, equipment, and training to help needy people around the world. Better Life Laboratories received no specific funding for this project from any donors. Donors to Better Life Laboratories provided no input in choosing the subject matter of this project, the materials selected to build the device, the brands or models of equipment selected for comparison, the method of analysis, the research findings, or the manner of disseminating the results. This does not alter our adherence to PLOS ONE policies on sharing data and materials. [Note: HTML markup is below. Please do not edit.] Reviewers' comments: Reviewer's Responses to Questions Comments to the Author 1. Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented. Reviewer #1: Yes Reviewer #2: No ________________________________________ 2. Has the statistical analysis been performed appropriately and rigorously? Reviewer #1: Yes Reviewer #2: No ________________________________________ 3. Have the authors made all data underlying the findings in their manuscript fully available? The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified. Reviewer #1: Yes Reviewer #2: No ________________________________________ 4. Is the manuscript presented in an intelligible fashion and written in standard English? PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here. Reviewer #1: Yes Reviewer #2: No ________________________________________ 5. Review Comments to the Author Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters) Reviewer #1: This manuscript describes the design and performance of an accurate and precise light emitting diode (LED) Spectrophotometer that costs approximately 63 U.S. dollars for parts, less than 2.6% of the cost of several commercial Spectrophotometers. The paper is well organized and clearly written. The technical quality of the manuscript is satisfactory but the length is too long in relation to technical impact. Although reducing of equipment’s cost is not novel in most cases, this study considered as a valuable longitudinal study since the LED Spectrophotometer was continuously designed, tested, and improved over a three-year period. I would recommend publish this this manuscript after minor corrections. Most regions of limited resources suffer from lack of availability of most components and that may affect the prices. I would recommend authors to consider this point in the motivation (in my knowledge these components are cheap in the industrial countries while the cost may be higher in regions of limited resources). REVISION MADE: We have added additional text to the Materials and Methods section to explain this point. Secondly, I would suggest authors to involve statistical variability in the analysis (optional or in the future work). REVISION MADE: We have expanded our section explaining our statistical analysis to make the analysis more clear. Reviewer #2: In this paper, a light emitting diode spectrophotometer was designed and implemented for drinking water and other testing with limited resources. However, I recommend rejecting the paper for the following reasons. 1. The novelty of the paper is not well presented. REVISION MADE: We have expanded the Introduction, and the Results and Discussion sections to more thoroughly explain the novelty of the paper. 2. The contributions in the fields of study wholly missing. REVISION MADE: We have expanded the Introduction, and the Results and Discussion sections to address this comment. We now include a more thorough literature review of the design, construction, and testing of other LED spectrophotometers in education and industry. These new expanded sections include 23 new references. 3. The paper is not well structured and organized. REVISION MADE: We have expanded the introduction, literature review, and Results and Discussion sections. We have also made the section headings more descriptive. We believe this improved the structure and organization of the paper. 4. More unnecessarily information and details were presented in the paper. REVISION MADE: We have revised the paper to make it more clear why we have chosen to present these details. 5. The introduction section is very poor and did not highlight the problem statement in the field of study. In addition, the previous solutions in this field were not discussed or investigated in the study. REVISION MADE: We have expanded the Introduction section to highlight the goals of the study as well as previous related works as presented in the literature. We have also added an explanation about how our study is novel. 6. The related works section is missing. REVISION MADE: We have expanded the Introduction to discuss previous related works. This new expanded Introduction includes 22 new references. 7. The study presents well-known information, not new for specialists. A major goal and a novel aspect of our paper is that we give enough information so that our spectrophotometer can be built, tested, and used by non-specialists. Our goal is to make all aspects of the design comprehensible to laboratory analytical chemists as well as electrical engineers. Thus, we do not assume any prior background knowledge about components of the design, even though the details may be familiar to some readers such as electrical engineers. 8. The “power unit and Light-emitting diode source circuit” they have been explained in detail though it is a simple electronic circuit. A major goal and a novel aspect of our paper is to provide enough information so that our spectrophotometer can be built, tested, and used by non-specialists. For our paper to be effective, we must provide sufficient detail so that a non-specialist in a resource-limited country or area has enough information to build, test, and use our LED spectrophotometer. 9. Equation (11), this equation is well known for the standard deviation. Why the authors named it "precision standard". REVISION MADE: Equation 11 and its associated text have been deleted. There are 3 different measures of precision in analytical chemistry: the precision of standards, the precision of samples, and the precision of known additions of standard to samples. The precision of standards is defined as the sample standard deviation from the repeated analyses of a single standard solution. 10. Table 1 is not necessary to present the price of the components, instead, the authors can present the specifications of the proposed design. REVISION MADE: We have included a new Figure (new Figure 1) to present the specifications of the design. However, we have also retained Table 1 as we believe it provides essential information to readers about which specific components that we used. It also provides a clear explanation of how we calculated the cost of $63 USD that we mention in the text. 11. Statistical analyses were not presented in a good manner. REVISION MADE: R2 and Bland-Altman plots have been added as requested. We have also expanded our explanation of using tests for higher order polynomial relationships to objectively test the linearity of calibration curves and to measure the upper limits of linear range in this study, and using control charts to estimate detection limits. 12. The linear regression (R2) must be presented as a figure to allow the reader to seen the improvement in correlation between proposed LED spectrophotometer and commercial spectrophotometer. REVISION MADE: As requested, the R2 values for every spectrophotometer and every analyte are shown together in a new figure, Fig 15. 13. The limits of agreement, better if it is measured under the Bland-Altman test. Where, the Bland-Altman test shows the upper and lower of agreement, difference of mean, standard deviation of difference. The difference here refers to the difference in measurement between proposed LED spectrophotometer and commercial spectrophotometer. REVISION MADE: Bland-Altman plots for each pairwise comparison of LED spectrophotometer #1 and the commercial spectrophotometers for each analyte have been added. 14. The resolution of Figs. 7-13. As specified by the journal, these figures are saved as TIFF with 300 dpi resolution. However, the figures may have been blurred when they were incorporated in the PDF for review. Clear 300 dpi images for all figures have been uploaded to the journal, but we cannot control their appearance in the preview PDF files. 15. The journal references are out of date. REVISION MADE: We have expanded our literature review and added 23 new references, many of which are very recent (only 1 or 2 years old). 16. Overall evolution, the paper is not well presented and organized, the contribution is missing, and the novelty is not clear. So, I recommend rejecting the paper for publication in a PLOS ONE Journal. We are very grateful to Reviewer #2 for thoughtfully reading our article and us giving very helpful feedback. Following the specific comments, we have improved the presentation, organization, and contribution to the field and more clearly explained the novel aspects of this project. The authors all agree that the current version of our manuscript is greatly improved as a result. Thank you very much for sharing your time and expertise. ________________________________________ 6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files. If you choose “no”, your identity will remain anonymous but your review may still be made public. Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy. Reviewer #1: No Reviewer #2: No [NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files to be viewed.] While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email us at figures@plos.org. Please note that Supporting Information files do not need this step. ________________________________________ In compliance with data protection regulations, you may request that we remove your personal registration details at any time. (Remove my information/details). Please contact the publication office if you have any questions. Attachments Attachment Submitted filename: Response to Reviewers.docx https://doi.org/10.1371/journal.pone.0226761.r002
6 Dec 2019 Decision Letter - Talib Al-Ameri, Editor An accurate, precise, and affordable light emitting diode spectrophotometer for drinking water and other testing with limited resources PONE-D-19-17629R1 Dear Dr. Frisbie, We are pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it complies with all outstanding technical requirements. Within one week, you will receive an e-mail containing information on the amendments required prior to publication. When all required modifications have been addressed, you will receive a formal acceptance letter and your manuscript will proceed to our production department and be scheduled for publication. Shortly after the formal acceptance letter is sent, an invoice for payment will follow. To ensure an efficient production and billing process, please log into Editorial Manager at https://www.editorialmanager.com/pone/, click the "Update My Information" link at the top of the page, and update your user information. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org. If your institution or institutions have a press office, please notify them about your upcoming paper to enable them to help maximize its impact. If they will be preparing press materials for this manuscript, you must inform our press team as soon as possible and no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org. With kind regards, Talib Al-Ameri, Ph.D Academic Editor PLOS ONE Additional Editor Comments (optional): Reviewers' comments: Reviewer's Responses to Questions Comments to the Author 1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation. Reviewer #2: All comments have been addressed ******** 2. Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented. Reviewer #2: Yes ****** 3. Has the statistical analysis been performed appropriately and rigorously? Reviewer #2: Yes ****** 4. Have the authors made all data underlying the findings in their manuscript fully available? The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified. Reviewer #2: Yes ****** 5. Is the manuscript presented in an intelligible fashion and written in standard English? PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here. Reviewer #2: Yes ****** 6. Review Comments to the Author Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters) Reviewer #2: I have carefully read the corrections that the authors did it. All my comments have been addressed, therefore I recommend to accept the paper without more corrections. ****** 7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files. If you choose “no”, your identity will remain anonymous but your review may still be made public. Do you want your identity to be public for this peer review?** For information about this choice, including consent withdrawal, please see our Privacy Policy. Reviewer #2: Yes: Sadik Kamel Gharghan https://doi.org/10.1371/journal.pone.0226761.r003
Formally Accepted
6 Jan 2020 Acceptance Letter - Talib Al-Ameri, Editor PONE-D-19-17629R1 An accurate, precise, and affordable light emitting diode spectrophotometer for drinking water and other testing with limited resources Dear Dr. Frisbie: I am pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department. If your institution or institutions have a press office, please notify them about your upcoming paper at this point, to enable them to help maximize its impact. If they will be preparing press materials for this manuscript, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org. For any other questions or concerns, please email plosone@plos.org. Thank you for submitting your work to PLOS ONE. With kind regards, PLOS ONE Editorial Office Staff on behalf of Dr. Talib Al-Ameri Academic Editor PLOS ONE https://doi.org/10.1371/journal.pone.0226761.r004

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